Hi Fred. The meter should be hooked up after the amp. Reason is: If you put it between the radio and amp it will only read the power going out of the radio and not of the amp. So put it after the amp to know how much is going out of the amp. IE: Iff your radio does 4 watts and the meter between the radio and amp it will only tell you 4 watts. I guess you'd like to know what is going out of the amp and not the radio. Therefor most of us hook up the meter after the amp.
I remember as a kid the antenna and "burner" that my dad had - whilst he wasnt a ham, he did keep a log which was fun to see, esp when the sporadic E kicked in.
The name of the game is big power here in the states. I prefer the ladder and run barefoot. Undoubtedly, I've done better with a foot warmer. I just prefer the sense of accomplishment when I reach the east coast without a box. 73 Triple 7's out of Oro Valley Arizona
Interesting video Fred. I think that meter is pretty accurate. Nice demonstration. You are so right in being careful of what you put into these amps. They won't last long with too much input power for sure.
The SWR meter goes last in the chain, at the antenna end. (Ideally, although not practical, it should be right at the end of the transmission line, at the antenna connection itself.)
99% of antennas do not offer a 50Ω impedance right at their feed point, it is the combination of the feed line/coax length together with the antenna's actual impedance that offer the (near) 50Ω impedance. This is why very often a better swr can be achieved by varying the coax length. Same with feeding the amplifier; if you don't want to mess around inside the amp, but you do have a high swr at the amplifier's input, you can often achieve an acceptable swr by varying the coax jumper length between radio and amplifier.
@@goatsinker347 "you do have a high swr at the amplifier's input, you can often achieve an acceptable swr by varying the coax jumper length between radio and amplifier." That's a measuring gimmick; if the amplifier is 25 ohms input and your radio is 50 ohms output you've got a 2:1 SWR even if the meter can be tricked into not seeing it.
Cheers for this Fred. I knew nothing about using linear amplifiers so this was good to watch. Clear and concise as always. My first ever go on a CB was an AM rig in the St. Albans college for further education way back 1980 or '81.
People are forgetting the definition of SWR....you want to measure what is reflecting back down the antenna, so meter needs to be hooked to antenna (not between radio and amp). Between radio and Amp, you are no longer measuring the performance of the antenna (that is what measuring SWR is about). After all, you want to adjust it's length, which controls the amount reflected back.
Put the meter after the Anp Fred that way you’ll be able to see the output from the amp.I run 400w and my meter is always after the amp to keep an eye on swr and power out👍
The meter between the radio and amp will measure the input tune of the amp. The meter placed between the amp and antenna will measure the reflect between the amp and antenna, which is very important so that you don't smoke your output transistors.
Look, change the ceramic filters for 2.5kHz crystal filters and load them accordingly (about 1.2K ohm). Peak for max RX signal. Your adjacent channel noise will be gone. Put one meter after the amp, then set your VSWR resonance for the antenna. Then you will transfer the meter to the radio input. See what the VSWR is. If it's high, above 1:1.6 then open up the PA and use the trimmers to give a good match to the radio. If there are no trimers, then add a 100-200pf ceramic trimer from the input to ground. Tune for lowest VSWR. Job done.
Hi Fred, just a note that when you were talking on AM the power meter was going backwards i.e. the power was reducing that is a sign your linear is being over driven and will distort. It’s really surprising considering your dead key is only 3.5 Watts on the Trueman, I guess the swing on AM is maybe only 1 - 2 Watts which tells me your amp is not linear much over 4 Watts in. You might need to reduce your dead key power down to 2 - 2.5 Watts to get it to swing up on AM to around the 50 Watt Mark with the amp on. Remember if the power starts going in reverse you are over driving and may distort or cause un wanted harmonics.
Don't talk BOLLOCKS. On AM, you will be running in class C, not AB1, that is for SSB (liner operation). Look, change the ceramic filters for 2.5kHz crystal filters and load them accordingly (about 1.2K ohm). Peak for max RX signal. Your adjacent channel noise will be gone. Put one meter after the amp, then set your VSWR resonance for the antenna. Then you will transfer the meter to the radio input. See what the VSWR is. If it's high, above 1:1.6 then open up the PA and use the trimmers to give a good match to the radio. If there are no trimers, then add a 100-200pf ceramic trimer from the input to ground. Tune for lowest VSWR. Job done.
That's garbage, the amplifier/PA stage for any mode where the amplitude changes with modulation needs to be linear, constant carrier modes like FM don't. Changing ceramic filters for crystal filters without making other changes to match the different input/output impedance correctly will make your radio less sensitive giving you a false impression that they're working. @@susanlodges48
find a way to decrease the dead key of the radio to 2 watts, that would put less stress on the componets in the linear and you should get more out of it aswell, most importantly, it will last longer
Fred we used to put our SWR meter at after the burner mainly because we would push about 800 watts ssb. it would depend on the day what Ariel use from a large quad (pdl2) or even a wire which ran over the house the reason for the wire it was split into different meters so one wire could do anything from 40 meters down to 2 meters. Dave (teapot or tango popa 35)
I've had this argument for years I've even put 2 set meters in line one before the burner and one after the burner ive found it's always safer to have it before the burner as when you set the swr after the burner it's always high at the radio. So this has been my conclusion but other people say that if you set your swr after the burner you drop the reflection so make up your own minds lol.
VSWR meter won’t work well between the amp and radio, it’ll work best at the very end, so after your amp. VSWR will be slightly different after the amp because there is more cable, more connections and also the amp before the meter. You want a little cable and connections as possible between the antenna and meter to get a good reading. Also you shouldn’t read VSWR with power anyway, you can of course but if you have a good VSWR before the amp is on, it shouldn’t be dangerously high after it’s turned on. If it is you have a problem.
Without watching the video.. Generally with 4w input you get 80w max output. Even on a 200w amp. I thought that was universally known. My SWR is 1.2 I have a 150w 4w input amp.. It gives me 70 - 80 watts on FM (pending on the meter) I also have a 35w with an 8w max input amp... I get 16 - 20w using a 4w input.. The thing gets warm but not hot and because Im not over stressing it, thats why its lived 35+ years. I started CB with a repaired multi stage 600w valve amp (repaired by myself at school)... My 8w rig output on am.fm would give me (bear in mind its 40 years ago) around 400 to 500w. Like a soldering iron, you only forget and burn yourself once on them. I get s3 noise at home... Turn off the phone chargers and the PC and the noise vanishes. When Im mobile I get pockets of 30+ electronic noise. Average noise is s3. CB --- amp --- SWR/power meter -- antenna ... The meter is always after the amp. Always initially SWR your antenna using just 4w bare rig power.
The power increase on AM from 4 to 40 watts, and on FM from 5 to 50 watts, shows about a 10 DB gain, or 10 times the unamplified power which is a nice incease for a small amplifier. W2CH
I find amps are more hassle than they are worth. My SWR would forever change so been put away forever I think. I run the CRT SS 6900 on full power on SSB and by fluke worked Mexico on propagation. Normally work Italy 3k from Gatwick Airport on half walf silver rod. All your recommendations Fred lol.
At the end for sure. Because you're calibrating the meter with what the power is you're getting two different ratings otherwise you're calibrating the meter power from the radio and then you're getting reflected back from the amp
I happen to be a professional RF engineer. Look, there are few things here. Change the ceramic filters for 2.5kHz crystal filters and load them accordingly (about 1.2K ohm). Peak for max RX signal. Your adjacent channel noise will be gone. Put one meter after the amp, then set your VSWR resonance for the antenna. Then you will transfer the meter to the radio input. See what the VSWR is. If it's high, above 1:1.6 then open up the PA and use the trimmers to give a good match to the radio. If there are no trimers, then add a 100-200pf ceramic trimer from the input to ground. Tune for lowest VSWR. or better still lowest return signal power. Cut the coax to multiples of an odd half wavelength taking into account the characteristic impedance of the coax Job done.
You should always run your power meter and SWR meter after the amplifier when using an amp you will get a true reading of your SWR normally if you have a good SWR without an amplifier you should not have a problem using an amp one other note these meters are not 100% accurate they are basically just a reference so you need to remember that also if you want to Accurate meter you're going to pay some really big bucks these meters for $100 $200 at best maybe 75% accurate
Hello Sir, your video is great. The SWR must be measured after the Amplified wave! Make sure your antenna and radio are properly grounded first. In a mobil i.e., car it's not the battery I speak of but the radio and antenna themselves. ( to the BODY of the car). In a base station an 8 foot copper rod into the ground to antenna and a separate wire from your radio to the same ground. I'm sure this is common knowledge to you yet I love to help. Also measuring output watts has two factors; average power and PEP peak envelope power. With that amp you tested your average was 50 but with a proper meter would swing to say 90 or 100 watts! Love your videos and hope this helps.. God Speed from U.S.A. 🍻 DB
Thanks david. With ref to homebased earthing you just need to check what type of earthing you house has. Sinking a copper rod near a Protective Multiple Earthing system is not a good idea.
Thanks Fred. This maybe true yet it gets rid of lots of static on AM band. I sure wish I could talk some skip with you! The farthest I've gotten was Portarico. I'm sure I spelled that wrong. DB
Look, change the ceramic filters for 2.5kHz crystal filters and load them accordingly (about 1.2K ohm). Peak for max RX signal. Your adjacent channel noise will be gone. Put one meter after the amp, then set your VSWR resonance for the antenna. Then you will transfer the meter to the radio input. See what the VSWR is. If it's high, above 1:1.6 then open up the PA and use the trimmers to give a good match to the radio. If there are no trimers, then add a 100-200pf ceramic trimer from the input to ground. Tune for lowest VSWR. Job done.
Zatagi equipment, know for over exaggerating what their equipment does. But yeah, you never get out what it says on the tin, but on SSB it should give it quite a kick.
@@CB-RADIO-UK Buy a set with the power already there inside it, that way there is no problems. Buy it with adjustable power, one that you can listen all over the bands. Just be careful.
Great video n it good check your pass true tune on your amp The way you puting meter is the way do it whith amp off If swr is much at all you won't hear as good as you shud N most amps you dont have as much power as thay say I know y'all use fm n thare no swing on am people see the swing think that graet lol But all that Maders is continuous watts you do need a litte Gowers swing N meter read all power even speris emissions off frequency that DON'T help at all I have 3 bird meters 2 43 n 1 4314c but o scope n the math don't lie . 707 I have meter like little one you thare good for tuning anttna N class c amps such on ssb N are not to clean I really enjoy your video's n look forward to your next
Those old boots would kick out about 80W all night long if you put about 3 watts in. It usually took about 4.5W and a really low SWR to get the full 100. I had a 300W Zetagi one that had a habit of melting aerials if you keyed up for too long. 😅
And if your using a omnl you have to divide it by 360 degrees.. Its actually more as the power is radiating out of the top of the antenna angles too in a doughnut shape.. The amount of power really is fantastically small rx, ed by the receiving station..
Apparently not to many operators here understand what S.W.R. is the abbreviation is for standing wave ratio this can only be measured between the transmission line and the antenna therefore the meter must be between the last transmission device and the antenna
Look, change the ceramic filters for 2.5kHz crystal filters and load them accordingly (about 1.2K ohm). Peak for max RX signal. Your adjacent channel noise will be gone. Put one meter after the amp, then set your VSWR resonance for the antenna. Then you will transfer the meter to the radio input. See what the VSWR is. If it's high, above 1:1.6 then open up the PA and use the trimmers to give a good match to the radio. If there are no trimers, then add a 100-200pf ceramic trimer from the input to ground. Tune for lowest VSWR. Job done. Use a low pass filter at the output to reduce out of band signals.
I have a 100 watt linear still in the box (i bought it just in case ) but i am able to talk longer distances and shoot skip without any trouble. I also believe using a linear for skip is like shooting fish in a barrel.
I agree. Shooting skip on 20 watts works just as well. Amps are good for local contacts with people who have high noise. For example if i contact Jake in Highgate he often has S7 of noise and i need a S9 to be heard.
Thanks for your time, Reading all the comments, I see that there are several options to correctly connect the station the SWR meter and the ampli and also see that some colleagues comment that it can be bad for the station according to what combination. Could someone make a summary for this topic to be clear? Cable that comes from the antenna connected to ... XXXXXX Output from the station connected to ..xxxxx Ampli - connection marked as RTX connected to .... XXXX Ampli - connection marked as ANT connected to .... XXXX SWR - Connection marked as ANT connected to .... XXXXX SWR - Connection marked as Transceiver connected to .... XXXX
Oh, SWR meter, put it between CB and Apmlifier to read SWR between CB and Amplifier, also read SWR with Amplifier off, after Amplifier to see SWR between Amplifier and aerial. Simples! Inserting an SWR meter in itself affects SWR and if you take it out you will get a different reading, may be tiny or more.
Use a low power SWR meter to adjust the antenna at Channel 1 and 40 to under 1:1,5. Remove the low power SWR and replace it with high power SWR/P meter (after the amp). With 80W o/p be sure to ground your gear effectively. 80W CB is illegal anyway. Keep it therefore, let's say illegaly, to about 16W max. It's good enough to get around the EU. Better invest your effort into a stationary multy Lamda dipol or even better, a Delta-Loop antenna.
That's untrue when you run your amplifier your SWR will always be a little bit higher because you're pushing power through the antenna you can have a flat SWR with no power and then your SWR could creep up to 1.5 with the amplifier on that's totally safe
Run your own test with two swr meters BUT they should be same brand and model to keep it as close as possible without all other variables if you use different brand meters . Have one next to the radio and one at the end and see what you get. You always get a bigger linear than you want because they tell you what the output is under idea or laboratory conditions. If you want 100 watts then get something that says 200 watts and you don’t have to run it hard just back it down to low or medium
"You always get a bigger linear than you want because they tell you what the output is under idea or laboratory conditions." Since there's no truth in advertising for illegal products and you have no idea what is a "watt" anyway, just get the biggest and shiniest you can afford. Make sure it has BLUE led's they are the best. I mean, how on earth could I decide "I want 200 watts". Is that RMS, is that Peak Envelope Power and what's an envelope anyway? (It is the RMS power of the transmitter at the moment of peak modulation). However, Peak to Peak power will be approximately 2.8 times the PEP which in turn is about 4 times more than dead key AM. It is all the same, but they can give much Bigger Numbers if they use Peak-to-Peak for labeling.
You need to put two POWR / SWR meters. On between the radio and the amplifier and one after the amplifier. Thats the best way. But once you tested that and everything looks as it should you could remove the one between de radio and the amplifier. I mean if you have the setup tested it probably will stay good. So one meter should be enough i think.
@@ve5uo No, they do not auto tune. They are really quite crude. Wherever you insert your VSWR meter, it will display the ratio of outgoing power against reflected power. Putting it between the radio and the RF amp is meaningless as it should be tuned to represent a near perfect 50 Ohm match.
I'[d like to see that Zetagi on a spectrum analyzer to see what the 2nd and 3rd harmonics look like. Upping your power through a splatter-box is not a clever move.
Just times the fundamental frequency by 2 or 3 and that will give you a ball park frequency. We tested a RM KL203 on a spectrum analyzer it was terrible above 60db on the 2nd harmonic. If people will insist on using them put a band pass filter between it and the aerial. Non of the so called C.B amplifier's have filtering in the P.A stages. You only have to look at the circuit diagrams to see. I won't call them linear's because they are far from it!!!!!
I just don't understand why they are illegal. Isn't a receiver preamp legal? It's a receiver preamp afterall. It just boosts the others guys receiver. lol
All the way through the CB heyday I never used or had interest in 'burners' although they were very common. So many badly set up rigs used to bleed over channels and otherwise cause chaos in the hands of the idiots and malicious. Now too old to camp on high ground for hours I suffer lack of contacts on 4 watts but see SSB and a better antenna as the way forward. I can understand in current conditions why people use them now though - it's lonely out there ! Been looking at magnetic loop antennas recently - any experience or advice to pass on ?
Hi John. Mag loops are quite pricey for CB. You can make your own and use coax. The hard part is finding the vari cap that can handle more than 10 watts in (QRP). You start looking at oil filled caps and the price jumps up. They are interesting though.
Please explain the advantage of using a linear amp because although you can reach out farther, the additional radios you reach can't respond to you because they're only transmitting at 4 watts.
Hi James. The main problem these days with home set ups is the high amount of QRM background noise. Some days you can be dealing with S7 or higher. The amp helps to boost your signal above that noise so the receiving station can hear you. Its not really about distance. On a perfect day 12 watts on SSB is plenty but with all the electronics crammed into a modern house perfect days are very few.
Exactly right. But the point isn't to talk to people using the legal 4 watts. The purpose of doing this is to talk over a thousand people using 4 watts and find the person with 400 watts. You and that person can then have a nice chat with a thousand people listening to it.
Hi Phil. Yes i did try a amp on SSB. For me and my local stations it was not worth the hassle getting the audio right. I stuck with standard power. Many others on the 305 use them ok though.
Ideally you want two vswr/power meters , Most aimed at CB vswr/power meters are pretty rubbish , Your vswr shouldn't alter much if anything at all from using a well designed amp .... I've heard and seen people say say that " Power affects set " ..... No it doesn't , Antenna resonance affects vswr , A four watt signal , Will have the same vswr as a hindered watt or even a Thousand watt signal , The main reason that people see their vswr go up when using a CB amp is due to its poor Input matching , A decent well constructed amplifier shouldn't alter the vswr , Obviously you readjust the vswr meter when going from low power to higher power if the vswr is single needle , Most cross needles vswr meters you just flick the switch to a higher scale to read the vswr or power .... There's lots of CB myths regarding Amps and antennas and coax ... Most are completely wrong but still get perpetuated even to this day .
"A four watt signal , Will have the same vswr as a hindered watt or even a Thousand watt signal " Hooray, someone gets it right. That's rare on this channel.
I was in full agreement on one of your previous videos where you mentioned the benefits of a good antenna. These amplifier are used to boost the transmitter power outside of legal power limits and should not be used in the U.K. These amplifier don’t just amplify the wanted signal but also any distortion and harmonic to a level that could be a problem to other spectrum users. Your power meter test don’t show how much of the transmitted power is actually on the frequency it’s needed. The SWR meter should be installed between the antenna and the linear amplifier. The input to the linear amplifier should have a roughly 50 ohm impedance it would therefore be entirely pointless to install the SWR meter between the radio and linear. You need to be very careful with how much rf power you put into the linear as again if you put to much power in it will produce horrible distortion products. Can I suggest you look at my videos on the Tiny Spectrum Analyser you may find this useful for basic radio testing or perhaps a SDR based spectrum Analyser ua-cam.com/video/FFgysm_HEFw/v-deo.html. This will help you identify any out of band distortion. The output from the linear will be terribly distorted long before the linear overheats and pops its clogs.
Hi. I don’t think many people are bothered that using amps cause he’ll for other users and that it’s illegal. It bothers me and my breaker buddies as we are trying to stay legal but increasingly have problems with high power rigs and burners blanking channels and destroying our hobby. Which some of us have been on for 40 years now. Thanks for an interesting video Fred.
What is an SDR based spectrum amplifier? You are talking bollocks. I happen to be a profession RF engineer. Look, change the ceramic filters for 2.5kHz crystal filters and load them accordingly (about 1.2K ohm). Peak for max RX signal. Your adjacent channel noise will be gone. Put one meter after the amp, then set your VSWR resonance for the antenna. Then you will transfer the meter to the radio input. See what the VSWR is. If it's high, above 1:1.6 then open up the PA and use the trimmers to give a good match to the radio. If there are no trimers, then add a 100-200pf ceramic trimer from the input to ground. Tune for lowest VSWR. or better still lowest return signal power. Cut the coax to multiples of an odd half wavelength taking into account the characteristic impedance of the coax Job done.
Hey Fred have you ever watched Colin Furs he doesn't do CB radio videos but he builds crazy inventions I just thought you might like him he lives in England too.
Now you put your your M before your amplifier through Reading and your 1.1 cuz you don't want all that wattage going through that m 100 amps it could burn that m
I am looking at getting a wee amp it is between the zetagi b150 or rm 200p would you recommend one of them over the other if i remember rite people use to prepare the older zetagi models
Power out is dependent on power in, you will never get 100w out of an amp with 4w in, my 100w amp gets fed the full 10w that its rated for and the difference in output vs being hooked to a 4w rig is huge!
*HAHA SO "NOT" !! .. LISTEN **#1WATT** IN **#1000WATT** "OUT" ....* *OK ...* *NR -2 ... **#1WATT** IN **#1300WATT** "OUT" .....* *OK...* *..... WHAT YOU SAY IS NOT "ALL WAYS" SO ..* NNNN ....
the comments section is filled with place it after and also place it before. please can someone clarify once and for all. otherwise this video shows nothing educationally.
@@adammegarry7929 "Ham radio only, cb the freeband is exempt" Nobody is exempt. The documentation threshold is set by EIRP (Effective isotropic radiated power). A LEGAL CB radio does not meet this threshold.
@@CB-RADIO-UK most radios are for mobiel and most dynamo's give more than 13.8 volts i have give most my radio's 15 volts not continuously but it give your more power if you need it
@@ZadenZane "Do you know is it proximity to their TV aerial or proximity to their actual TV that is the biggest factor interference-wise?" The antennas. Your transmitter can be right next to the television withough much effect (usually) because the television gets its signal from its antenna. The phenomenon that causes most interference is IMD, inter-modulation distortion. That happens with corroded antenna connections very common with the typical aluminum antenna. Aluminum oxide is a semiconductor and essentially re-modulates some of the energy causing harmonics and mixing the harmonics EVEN IF your transmitter is absolutely pure (which no CB amplifier is, they're illegal after all). Any metal-to-metal junction of dissimilar metals can do it; the chain link fence, the garage door pieces, metal shelving in your house or garage. I sometimes hear an AM broadcast station WAY off frequency but it isn't the transmitter's fault; just some nearby metal rectifying and modulating (intermodulation) the signal. en.wikipedia.org/wiki/Intermodulation
@@thomasmaughan4798 what about some of those ham radio sets that put out 100w on the 10m band/whatever, are those also bad for TV? That's a bit offputting for anyone wanting to get into amateur radio who has adjacent neighbours!
Those new president radios are not worth buying they don't have the punch like the rci galaxy and Stryker and the longhorn radios I use a rci 2950dx and a antron 99 about 50 feet up in the and I don't use a liner I talk all over the USA barefoot the rci has been peaked and tuned and inlined
Oh for heavens sake. Nothing like a bit of CB foolishness to make amusement. The SWR at the amplfiier will almost always NOT be the SWR at the CB Radio; and that's because of the transistor(s) in the path. The CB radio should never see "SWR" when connected to the amplifier provided the amplifier has a 50 ohm input impedance. It will always be 1:1 SWR no matter how terrible is the SWR at the antenna terminal. So, always put your SWR meter on the output of the amplifier to see the SWR coming from the antenna. It is useful to briefly have it at the output of the CB and input of the amplifier to see if the amplifier is really 50 ohms input. That is to say, you should never, ever, see anything other than 1:1 perfect (nonexistent) SWR between CB and amplifier. But of course, since doing all that is illegal anyway, who cares that you are doing it wrong.
@@CB-RADIO-UK A problem with Chinese amplifiers tends to be too low of input impedance. It isn't really much of a problem but it can produce erratic SWR measurements between radio and amplifier. My enjoyment of this kind of channel is the bewilderment that some must feel on getting hundreds of totally contradictory comments. Do this, no don't do that; do something else. It's great. No, it's crap. Interestingly, ham radio channels have similar conflicted advice where half have it more or less right, half have it pretty much wrong but it worked anyway because radios are pretty tolerant and the difference between 10 watts and 60 watts is 1 S-unit. It might make a difference but usually not. That's why the new big thing in ham radio is little things; low power battery operated radios. It's like fishing with a light rod and line; it requires some skill and finesse and is more enjoyable. Anyone with a kilowatt can blast through the sky. That's easy. No skill.
Hi Fred. The meter should be hooked up after the amp. Reason is: If you put it between the radio and amp it will only read the power going out of the radio and not of the amp. So put it after the amp to know how much is going out of the amp. IE: Iff your radio does 4 watts and the meter between the radio and amp it will only tell you 4 watts. I guess you'd like to know what is going out of the amp and not the radio. Therefor most of us hook up the meter after the amp.
I remember as a kid the antenna and "burner" that my dad had - whilst he wasnt a ham, he did keep a log which was fun to see, esp when the sporadic E kicked in.
The name of the game is big power here in the states. I prefer the ladder and run barefoot. Undoubtedly, I've done better with a foot warmer. I just prefer the sense of accomplishment when I reach the east coast without a box.
73
Triple 7's out of Oro Valley Arizona
Interesting video Fred. I think that meter is pretty accurate. Nice demonstration. You are so right in being careful of what you put into these amps. They won't last long with too much input power for sure.
I would guess the meter is prob 10% + or -. These little amps dont need a lot to drive them esp on SSB. Cheers bud
To measure true reflected power back to the radio the swr meter needs to be connected directly after the radio before any tuning units or amplifiers.
The SWR meter goes last in the chain, at the antenna end. (Ideally, although not practical, it should be right at the end of the transmission line, at the antenna connection itself.)
99% of antennas do not offer a 50Ω impedance right at their feed point, it is the combination of the feed line/coax length together with the antenna's actual impedance that offer the (near) 50Ω impedance. This is why very often a better swr can be achieved by varying the coax length. Same with feeding the amplifier; if you don't want to mess around inside the amp, but you do have a high swr at the amplifier's input, you can often achieve an acceptable swr by varying the coax jumper length between radio and amplifier.
@@goatsinker347 "you do have a high swr at the amplifier's input, you can often achieve an acceptable swr by varying the coax jumper length between radio and amplifier."
That's a measuring gimmick; if the amplifier is 25 ohms input and your radio is 50 ohms output you've got a 2:1 SWR even if the meter can be tricked into not seeing it.
Cheers for this Fred. I knew nothing about using linear amplifiers so this was good to watch. Clear and concise as always.
My first ever go on a CB was an AM rig in the St. Albans college for further education way back 1980 or '81.
Just down the road from me Pete
I'd have been around 19 then so jyst that bit older than you 🙂 I remember it was all very exciting and such a new technology for us at the time
I lived in Hemel Hempstead back then
People are forgetting the definition of SWR....you want to measure what is reflecting back down the antenna, so meter needs to be hooked to antenna (not between radio and amp). Between radio and Amp, you are no longer measuring the performance of the antenna (that is what measuring SWR is about). After all, you want to adjust it's length, which controls the amount reflected back.
Put the meter after the Anp Fred that way you’ll be able to see the output from the amp.I run 400w and my meter is always after the amp to keep an eye on swr and power out👍
The meter between the radio and amp will measure the input tune of the amp. The meter placed between the amp and antenna will measure the reflect between the amp and antenna, which is very important so that you don't smoke your output transistors.
Look, change the ceramic filters for 2.5kHz crystal filters and load them accordingly (about 1.2K ohm). Peak for max RX signal. Your adjacent channel noise will be gone. Put one meter after the amp, then set your VSWR resonance for the antenna. Then you will transfer the meter to the radio input. See what the VSWR is. If it's high, above 1:1.6 then open up the PA and use the trimmers to give a good match to the radio. If there are no trimers, then add a 100-200pf ceramic trimer from the input to ground. Tune for lowest VSWR. Job done.
100w is plenty for mobile and home use when conditions are right you will be heard on 12w or 100w. I think Good audio is most important
Hi Fred, just a note that when you were talking on AM the power meter was going backwards i.e. the power was reducing that is a sign your linear is being over driven and will distort. It’s really surprising considering your dead key is only 3.5 Watts on the Trueman, I guess the swing on AM is maybe only 1 - 2 Watts which tells me your amp is not linear much over 4 Watts in. You might need to reduce your dead key power down to 2 - 2.5 Watts to get it to swing up on AM to around the 50 Watt Mark with the amp on. Remember if the power starts going in reverse you are over driving and may distort or cause un wanted harmonics.
Great comments and explanation thanks.
Don't talk BOLLOCKS. On AM, you will be running in class C, not AB1, that is for SSB (liner operation). Look, change the ceramic filters for 2.5kHz crystal filters and load them accordingly (about 1.2K ohm). Peak for max RX signal. Your adjacent channel noise will be gone. Put one meter after the amp, then set your VSWR resonance for the antenna. Then you will transfer the meter to the radio input. See what the VSWR is. If it's high, above 1:1.6 then open up the PA and use the trimmers to give a good match to the radio. If there are no trimers, then add a 100-200pf ceramic trimer from the input to ground. Tune for lowest VSWR. Job done.
@@susanlodges48 totally correct
That's garbage, the amplifier/PA stage for any mode where the amplitude changes with modulation needs to be linear, constant carrier modes like FM don't.
Changing ceramic filters for crystal filters without making other changes to match the different input/output impedance correctly will make your radio less sensitive giving you a false impression that they're working.
@@susanlodges48
find a way to decrease the dead key of the radio to 2 watts, that would put less stress on the componets in the linear and you should get more out of it aswell, most importantly, it will last longer
Good advice.
Fred we used to put our SWR meter at after the burner mainly because we would push about 800 watts ssb. it would depend on the day what Ariel use from a large quad (pdl2) or even a wire which ran over the house the reason for the wire it was split into different meters so one wire could do anything from 40 meters down to 2 meters.
Dave (teapot or tango popa 35)
I've had this argument for years I've even put 2 set meters in line one before the burner and one after the burner ive found it's always safer to have it before the burner as when you set the swr after the burner it's always high at the radio. So this has been my conclusion but other people say that if you set your swr after the burner you drop the reflection so make up your own minds lol.
That's how I do it.
VSWR meter won’t work well between the amp and radio, it’ll work best at the very end, so after your amp. VSWR will be slightly different after the amp because there is more cable, more connections and also the amp before the meter. You want a little cable and connections as possible between the antenna and meter to get a good reading.
Also you shouldn’t read VSWR with power anyway, you can of course but if you have a good VSWR before the amp is on, it shouldn’t be dangerously high after it’s turned on. If it is you have a problem.
Without watching the video..
Generally with 4w input you get 80w max output. Even on a 200w amp. I thought that was universally known.
My SWR is 1.2
I have a 150w 4w input amp.. It gives me 70 - 80 watts on FM (pending on the meter)
I also have a 35w with an 8w max input amp... I get 16 - 20w using a 4w input.. The thing gets warm but not hot and because Im not over stressing it, thats why its lived 35+ years.
I started CB with a repaired multi stage 600w valve amp (repaired by myself at school)... My 8w rig output on am.fm would give me (bear in mind its 40 years ago) around 400 to 500w. Like a soldering iron, you only forget and burn yourself once on them.
I get s3 noise at home... Turn off the phone chargers and the PC and the noise vanishes.
When Im mobile I get pockets of 30+ electronic noise. Average noise is s3.
CB --- amp --- SWR/power meter -- antenna ... The meter is always after the amp.
Always initially SWR your antenna using just 4w bare rig power.
Lock downs are increasing mate, air ways will pick up again. Take care mate!
The power increase on AM from 4 to
40 watts, and on FM from 5 to 50 watts,
shows about a 10 DB gain, or 10 times
the unamplified power which is a nice
incease for a small amplifier. W2CH
no side band no bullocks !! good video mate !! ttfn
Loved the amps cranked them right up back in the day 😂
I find amps are more hassle than they are worth. My SWR would forever change so been put away forever I think. I run the CRT SS 6900 on full power on SSB and by fluke worked Mexico on propagation. Normally work Italy 3k from Gatwick Airport on half walf silver rod. All your recommendations Fred lol.
At the end for sure. Because you're calibrating the meter with what the power is you're getting two different ratings otherwise you're calibrating the meter power from the radio and then you're getting reflected back from the amp
I happen to be a professional RF engineer. Look, there are few things here. Change the ceramic filters for 2.5kHz crystal filters and load them accordingly (about 1.2K ohm). Peak for max RX signal. Your adjacent channel noise will be gone. Put one meter after the amp, then set your VSWR resonance for the antenna. Then you will transfer the meter to the radio input. See what the VSWR is. If it's high, above 1:1.6 then open up the PA and use the trimmers to give a good match to the radio. If there are no trimers, then add a 100-200pf ceramic trimer from the input to ground. Tune for lowest VSWR. or better still lowest return signal power. Cut the coax to multiples of an odd half wavelength taking into account the characteristic impedance of the coax Job done.
after the amp fred thats why ham swr/tuners are rated at a kw or more
You should always run your power meter and SWR meter after the amplifier when using an amp you will get a true reading of your SWR normally if you have a good SWR without an amplifier you should not have a problem using an amp one other note these meters are not 100% accurate they are basically just a reference so you need to remember that also if you want to Accurate meter you're going to pay some really big bucks these meters for $100 $200 at best maybe 75% accurate
Hello Sir, your video is great. The SWR must be measured after the Amplified wave! Make sure your antenna and radio are properly grounded first. In a mobil i.e., car it's not the battery I speak of but the radio and antenna themselves. ( to the BODY of the car). In a base station an 8 foot copper rod into the ground to antenna and a separate wire from your radio to the same ground. I'm sure this is common knowledge to you yet I love to help. Also measuring output watts has two factors; average power and PEP peak envelope power. With that amp you tested your average was 50 but with a proper meter would swing to say 90 or 100 watts! Love your videos and hope this helps.. God Speed from U.S.A. 🍻 DB
Thanks david. With ref to homebased earthing you just need to check what type of earthing you house has. Sinking a copper rod near a Protective Multiple Earthing system is not a good idea.
Thanks Fred. This maybe true yet it gets rid of lots of static on AM band. I sure wish I could talk some skip with you! The farthest I've gotten was Portarico. I'm sure I spelled that wrong. DB
@@adonikam1 Yeah i wish the AM skip was in. Iam hopeful. All the best bud.
Look, change the ceramic filters for 2.5kHz crystal filters and load them accordingly (about 1.2K ohm). Peak for max RX signal. Your adjacent channel noise will be gone. Put one meter after the amp, then set your VSWR resonance for the antenna. Then you will transfer the meter to the radio input. See what the VSWR is. If it's high, above 1:1.6 then open up the PA and use the trimmers to give a good match to the radio. If there are no trimers, then add a 100-200pf ceramic trimer from the input to ground. Tune for lowest VSWR. Job done.
I use the SWR last in series so I can see what piece is generating what output. My preference.
Zatagi equipment, know for over exaggerating what their equipment does. But yeah, you never get out what it says on the tin, but on SSB it should give it quite a kick.
Yes it would prob output close to 100 watts SSB. However these smaller cheap amps can be very fussy with audio compressing it.
@@CB-RADIO-UK Buy a set with the power already there inside it, that way there is no problems. Buy it with adjustable power, one that you can listen all over the bands. Just be careful.
After the amp. No doubt
Great video n it good check your pass true tune on your amp
The way you puting meter is the way do it whith amp off
If swr is much at all you won't hear as good as you shud
N most amps you dont have as much power as thay say
I know y'all use fm n thare no swing on am people see the swing think that graet lol
But all that Maders is continuous watts you do need a litte Gowers swing
N meter read all power even speris emissions off frequency that DON'T help at all
I have 3 bird meters 2 43 n 1 4314c but o scope n the math don't lie . 707
I have meter like little one you thare good for tuning anttna
N class c amps such on ssb
N are not to clean
I really enjoy your video's n look forward to your next
The infamous 'Zetagi' Watts 😂😂
Those old boots would kick out about 80W all night long if you put about 3 watts in.
It usually took about 4.5W and a really low SWR to get the full 100.
I had a 300W Zetagi one that had a habit of melting aerials if you keyed up for too long. 😅
And if your using a omnl you have to divide it by 360 degrees.. Its actually more as the power is radiating out of the top of the antenna angles too in a doughnut shape.. The amount of power really is fantastically small rx, ed by the receiving station..
Fred after the radio
Apparently not to many operators here understand what S.W.R. is the abbreviation is for standing wave ratio this can only be measured between the transmission line and the antenna therefore the meter must be between the last transmission device and the antenna
Swr always goes after the amp as first stated
Look, change the ceramic filters for 2.5kHz crystal filters and load them accordingly (about 1.2K ohm). Peak for max RX signal. Your adjacent channel noise will be gone. Put one meter after the amp, then set your VSWR resonance for the antenna. Then you will transfer the meter to the radio input. See what the VSWR is. If it's high, above 1:1.6 then open up the PA and use the trimmers to give a good match to the radio. If there are no trimers, then add a 100-200pf ceramic trimer from the input to ground. Tune for lowest VSWR. Job done. Use a low pass filter at the output to reduce out of band signals.
If the meter was fused, i would say close to the amp. Then it would not send a signal overload to reach the radio.
I have a 100 watt linear still in the box (i bought it just in case ) but i am able to talk longer distances and shoot skip without any trouble.
I also believe using a linear for skip is like shooting fish in a barrel.
I agree. Shooting skip on 20 watts works just as well. Amps are good for local contacts with people who have high noise. For example if i contact Jake in Highgate he often has S7 of noise and i need a S9 to be heard.
@@CB-RADIO-UK 👍
If you can read PEP, peak envelope power, it will do 100W on AM. 50W on FM is pretty accurate.
Thanks for your time,
Reading all the comments, I see that there are several options to correctly connect the station the SWR meter and the ampli and also see that some colleagues comment that it can be bad for the station according to what combination.
Could someone make a summary for this topic to be clear?
Cable that comes from the antenna connected to ... XXXXXX
Output from the station connected to ..xxxxx
Ampli - connection marked as RTX connected to .... XXXX
Ampli - connection marked as ANT connected to .... XXXX
SWR - Connection marked as ANT connected to .... XXXXX
SWR - Connection marked as Transceiver connected to .... XXXX
Used a 667 lots range on cb
Swr should by measured after the amplifier
Oh, SWR meter, put it between CB and Apmlifier to read SWR between CB and Amplifier, also read SWR with Amplifier off, after Amplifier to see SWR between Amplifier and aerial. Simples! Inserting an SWR meter in itself affects SWR and if you take it out you will get a different reading, may be tiny or more.
You should never have the meter after the radio it should always be the last thing before the antenna
Use a low power SWR meter to adjust the antenna at Channel 1 and 40 to under 1:1,5. Remove the low power SWR and replace it with high power SWR/P meter (after the amp). With 80W o/p be sure to ground your gear effectively. 80W CB is illegal anyway. Keep it therefore, let's say illegaly, to about 16W max. It's good enough to get around the EU.
Better invest your effort into a stationary multy Lamda dipol or even better, a Delta-Loop antenna.
That's untrue when you run your amplifier your SWR will always be a little bit higher because you're pushing power through the antenna you can have a flat SWR with no power and then your SWR could creep up to 1.5 with the amplifier on that's totally safe
Run your own test with two swr meters BUT they should be same brand and model to keep it as close as possible without all other variables if you use different brand meters . Have one next to the radio and one at the end and see what you get. You always get a bigger linear than you want because they tell you what the output is under idea or laboratory conditions. If you want 100 watts then get something that says 200 watts and you don’t have to run it hard just back it down to low or medium
I wouldn't suggest 2 SWR meters at the same time, the more patch leads you have giving you more ohm leakage.
"You always get a bigger linear than you want because they tell you what the output is under idea or laboratory conditions."
Since there's no truth in advertising for illegal products and you have no idea what is a "watt" anyway, just get the biggest and shiniest you can afford. Make sure it has BLUE led's they are the best.
I mean, how on earth could I decide "I want 200 watts". Is that RMS, is that Peak Envelope Power and what's an envelope anyway? (It is the RMS power of the transmitter at the moment of peak modulation). However, Peak to Peak power will be approximately 2.8 times the PEP which in turn is about 4 times more than dead key AM. It is all the same, but they can give much Bigger Numbers if they use Peak-to-Peak for labeling.
You need to put two POWR / SWR meters. On between the radio and the amplifier and one after the amplifier. Thats the best way. But once you tested that and everything looks as it should you could remove the one between de radio and the amplifier. I mean if you have the setup tested it probably will stay good. So one meter should be enough i think.
good evening Fred yet another good video mate 👍👍👍👍👍👍👍👍😊😊😊😉😉😉😉😎😎😎
If you want to measure the VSWR of your antenna, put your meter next to the antenna.
Your 'linear' has its own matching network in it.
Thanks Tony
Does it? I don't think these amplifiers have provisions for auto tuning.
@@ve5uo No, they do not auto tune. They are really quite crude.
Wherever you insert your VSWR meter, it will display the ratio of outgoing power against reflected power. Putting it between the radio and the RF amp is meaningless as it should be tuned to represent a near perfect 50 Ohm match.
I'[d like to see that Zetagi on a spectrum analyzer to see what the 2nd and 3rd harmonics look like. Upping your power through a splatter-box is not a clever move.
I doubt it would be very clean. These small amps are built to a cheap price.
Just times the fundamental frequency by 2 or 3 and that will give you a ball park frequency. We tested a RM KL203 on a spectrum analyzer it was terrible above 60db on the 2nd harmonic. If people will insist on using them put a band pass filter between it and the aerial. Non of the so called C.B amplifier's have filtering in the P.A stages. You only have to look at the circuit diagrams to see. I won't call them linear's because they are far from it!!!!!
Sometimes, you're just better off building your own amplifier. 😉
I'm a trucker. There's a trucker we call duck duck that has a 50 mile range on his radio from his truck and I've been trying to figure out how
I guess big antenna and a big pil amp.
I think they just x10 the input power so if u gave it 10w in you would get 100w put of the amp
I just don't understand why they are illegal. Isn't a receiver preamp legal? It's a receiver preamp afterall. It just boosts the others guys receiver. lol
They output too much power to be legal. Pre amps are fine. :-)
I put mine after the amplifier due to it being power/swr
You will also get a more Accurate power reading
i think i need a whiskey
Great info!
Too bad there are no opinions on how and where to measure SWR. I was hoping to find some helpful advice
I did have a video up about that but cannot find it. maybe i took it down for some reason.
@@CB-RADIO-UK Great presentation and very good video. My SWR stays in the acceptable range below 1.5 at the antenna and feed so I'm safe
Copy that.
All the way through the CB heyday I never used or had interest in 'burners' although they were very common. So many badly set up rigs used to bleed over channels and otherwise cause chaos in the hands of the idiots and malicious. Now too old to camp on high ground for hours I suffer lack of contacts on 4 watts but see SSB and a better antenna as the way forward. I can understand in current conditions why people use them now though - it's lonely out there ! Been looking at magnetic loop antennas recently - any experience or advice to pass on ?
Hi John. Mag loops are quite pricey for CB. You can make your own and use coax. The hard part is finding the vari cap that can handle more than 10 watts in (QRP). You start looking at oil filled caps and the price jumps up. They are interesting though.
You can run an old hf rig and get 100 watts sideband clean!
you can see in my id picture, RADIO>AMPLIFIER>SWR/WATT METER>ANTENNA
I had one that did a 1000 watts.
Please explain the advantage of using a linear amp because although you can reach out farther, the additional radios you reach can't respond to you because they're only transmitting at 4 watts.
Hi James. The main problem these days with home set ups is the high amount of QRM background noise. Some days you can be dealing with S7 or higher. The amp helps to boost your signal above that noise so the receiving station can hear you. Its not really about distance. On a perfect day 12 watts on SSB is plenty but with all the electronics crammed into a modern house perfect days are very few.
Exactly right. But the point isn't to talk to people using the legal 4 watts. The purpose of doing this is to talk over a thousand people using 4 watts and find the person with 400 watts. You and that person can then have a nice chat with a thousand people listening to it.
i push out about 23 to 24 amp with my radio but i haven't asmy radio on for like 2 months
You mention not using an Amp on ssb. Have you ever tried it out of interest. I've never.
Hi Phil. Yes i did try a amp on SSB. For me and my local stations it was not worth the hassle getting the audio right. I stuck with standard power. Many others on the 305 use them ok though.
i thou the maxium watt on fm is 4 u can use without getting report
Yes the max is 4 watt FM / AM
Take care Fred.....Bob
Thanks Bob
Its not about what wattage u got its all about ya aireal or how high you are if mobile
Height can be might to a point but it also depends whats in the way and the amount of noise the receiving station is dealing with.
Ideally you want two vswr/power meters , Most aimed at CB vswr/power meters are pretty rubbish , Your vswr shouldn't alter much if anything at all from using a well designed amp .... I've heard and seen people say say that " Power affects set " ..... No it doesn't , Antenna resonance affects vswr , A four watt signal , Will have the same vswr as a hindered watt or even a Thousand watt signal , The main reason that people see their vswr go up when using a CB amp is due to its poor Input matching , A decent well constructed amplifier shouldn't alter the vswr , Obviously you readjust the vswr meter when going from low power to higher power if the vswr is single needle , Most cross needles vswr meters you just flick the switch to a higher scale to read the vswr or power .... There's lots of CB myths regarding Amps and antennas and coax ... Most are completely wrong but still get perpetuated even to this day .
"A four watt signal , Will have the same vswr as a hindered watt or even a Thousand watt signal "
Hooray, someone gets it right. That's rare on this channel.
I love how Chicken Banders explain technical topics.
It's all a load of bu//Sh/t , but it's fun to listen to for a laugh :-)
I was in full agreement on one of your previous videos where you mentioned the benefits of a good antenna. These amplifier are used to boost the transmitter power outside of legal power limits and should not be used in the U.K. These amplifier don’t just amplify the wanted signal but also any distortion and harmonic to a level that could be a problem to other spectrum users. Your power meter test don’t show how much of the transmitted power is actually on the frequency it’s needed. The SWR meter should be installed between the antenna and the linear amplifier. The input to the linear amplifier should have a roughly 50 ohm impedance it would therefore be entirely pointless to install the SWR meter between the radio and linear. You need to be very careful with how much rf power you put into the linear as again if you put to much power in it will produce horrible distortion products. Can I suggest you look at my videos on the Tiny Spectrum Analyser you may find this useful for basic radio testing or perhaps a SDR based spectrum Analyser ua-cam.com/video/FFgysm_HEFw/v-deo.html. This will help you identify any out of band distortion. The output from the linear will be terribly distorted long before the linear overheats and pops its clogs.
Hi. I don’t think many people are bothered that using amps cause he’ll for other users and that it’s illegal. It bothers me and my breaker buddies as we are trying to stay legal but increasingly have problems with high power rigs and burners blanking channels and destroying our hobby. Which some of us have been on for 40 years now. Thanks for an interesting video Fred.
What is an SDR based spectrum amplifier? You are talking bollocks. I happen to be a profession RF engineer. Look, change the ceramic filters for 2.5kHz crystal filters and load them accordingly (about 1.2K ohm). Peak for max RX signal. Your adjacent channel noise will be gone. Put one meter after the amp, then set your VSWR resonance for the antenna. Then you will transfer the meter to the radio input. See what the VSWR is. If it's high, above 1:1.6 then open up the PA and use the trimmers to give a good match to the radio. If there are no trimers, then add a 100-200pf ceramic trimer from the input to ground. Tune for lowest VSWR. or better still lowest return signal power. Cut the coax to multiples of an odd half wavelength taking into account the characteristic impedance of the coax Job done.
@@susanlodges48 I assume you meant to say SDR based spectrum analyser. Professional LOL.
Amazing videos man been using the crt6900 for a while looking to upgrade to the ft450d just wondering will it transmit on 11m out the box
Hi. No you will need it to be widebanded. This can be done at the time of purchase so to keep the warranty if you buy new.
You can't test it on SSB without a two-tone generator set to 25KHz.
I would be worth mentioning that burners are illegal in the U.K. People that are new to the hobby may not know this!!!!!
Yes good point. ive added it in the description.
Can you similarly amplify a vhf uhf radio? If yes, is it needed? When is it needed?
In theory you can boost a VHF radio like a UV5R but ive never tried. You can get handhelds which run at 10 watts
Hey Fred have you ever watched Colin Furs he doesn't do CB radio videos but he builds crazy inventions I just thought you might like him he lives in England too.
Hi Yes ive been a subbed fan of Mr Furze since he built the "wall of death" from pallets. :-)
Hello is 17 amps with continuous 15 amps power supply too little for a cb radio with maximum consumes 10 amp?
Hi. Should be fine.
@@CB-RADIO-UK Okey thank you I try this 😊
Now you put your your M before your amplifier through Reading and your 1.1 cuz you don't want all that wattage going through that m 100 amps it could burn that m
Good point
Its getting hot so quickly because you are overdriving it,you should not use more than 2 watts in for bedt results
I am looking at getting a wee amp it is between the zetagi b150 or rm 200p would you recommend one of them over the other if i remember rite people use to prepare the older zetagi models
Personally i prefer the B150 as the relay seems to work better.
@@CB-RADIO-UK Thanking you
BBI Fred lol Goodtest B150p good little AMP Zetagi amps are the best better than KLM AMPs 73s
woffal woffal polly waffal radio check 🤣🤣🤣
Power out is dependent on power in, you will never get 100w out of an amp with 4w in, my 100w amp gets fed the full 10w that its rated for and the difference in output vs being hooked to a 4w rig is huge!
*HAHA SO "NOT" !! .. LISTEN **#1WATT** IN **#1000WATT** "OUT" ....*
*OK ...*
*NR -2 ... **#1WATT** IN **#1300WATT** "OUT" .....*
*OK...*
*..... WHAT YOU SAY IS NOT "ALL WAYS" SO ..*
NNNN ....
Greetings from Andorra.
I have the same SWR meter and also a small amp.
What is the correct way to connect it all?
Thanks a lot
HI. I set up. RADIO - SWR - AMP. Unless you want to use the SWR meter as a power meter then i place it at the end.
the comments section is filled with place it after and also place it before. please can someone clarify once and for all. otherwise this video shows nothing educationally.
100Watt on cb wattmeter is like 65Watt in real.
Yes plus you lose power down to the coax run so what you end up with at the antenna is less.
Ofcom have a new regulation that if your using more than 10watts you have to submit an rf report , has anyone seen this ?
Ham radio only, cb the freeband is exempt
@@adammegarry7929 "Ham radio only, cb the freeband is exempt"
Nobody is exempt. The documentation threshold is set by EIRP (Effective isotropic radiated power). A LEGAL CB radio does not meet this threshold.
Put it next to radio
13.8 volt power supply or 15 volt make difference in watt
Prob not. Most radios and amps are designed for a max of 13.8v. If you put 15 volts into a CRT 6900 / 9900 you would trip a Hi DC warning.
@@CB-RADIO-UK most radios are for mobiel and most dynamo's give more than 13.8 volts i have give most my radio's 15 volts not continuously but it give your more power if you need it
@@CB-RADIO-UK look in you manual tdc on or off tdc on Dc 10.5-16V page 17 www.manualslib.com/manual/640232/Crt-Ss-6900.html?page=17
Don't those things interfere with neighbours' TV signals, or is that an urban myth?
Yes they can do. No where near as bad with digital tv.
@@CB-RADIO-UK Do you know is it proximity to their TV aerial or proximity to their actual TV that is the biggest factor interference-wise?
CB amplifiers tend to have terrible interference to anyone still using an antenna for television.
@@ZadenZane "Do you know is it proximity to their TV aerial or proximity to their actual TV that is the biggest factor interference-wise?"
The antennas. Your transmitter can be right next to the television withough much effect (usually) because the television gets its signal from its antenna.
The phenomenon that causes most interference is IMD, inter-modulation distortion. That happens with corroded antenna connections very common with the typical aluminum antenna. Aluminum oxide is a semiconductor and essentially re-modulates some of the energy causing harmonics and mixing the harmonics EVEN IF your transmitter is absolutely pure (which no CB amplifier is, they're illegal after all).
Any metal-to-metal junction of dissimilar metals can do it; the chain link fence, the garage door pieces, metal shelving in your house or garage. I sometimes hear an AM broadcast station WAY off frequency but it isn't the transmitter's fault; just some nearby metal rectifying and modulating (intermodulation) the signal.
en.wikipedia.org/wiki/Intermodulation
@@thomasmaughan4798 what about some of those ham radio sets that put out 100w on the 10m band/whatever, are those also bad for TV? That's a bit offputting for anyone wanting to get into amateur radio who has adjacent neighbours!
Read what power supply Would I need 4 cobra 148
Around 15 amp would be ideal.
@@CB-RADIO-UK
Forward for your help
Please keep doing the videos
I have a wildlife 300 how many amps do I need. With a cobra
138 xlr.
Hi. I dont know the amp but if its 300 watt i would look at a 30 amp supply min, maybe more.
As many wats as you can afford. Doing 2000 out of my mobile.
What is meant by "headroom"?
Expansion. Breathing room etc.
hi fred if i what to make a dipole how loung do i need the cable
Start at around 2m 65cm per side and adjust swr from there.
@@CB-RADIO-UK ok fred cheeks I will try that
Those new president radios are not worth buying they don't have the punch like the rci galaxy and Stryker and the longhorn radios I use a rci 2950dx and a antron 99 about 50 feet up in the and I don't use a liner I talk all over the USA barefoot the rci has been peaked and tuned and inlined
Same here WITH a President radio. I'm told I sound loud and proud. 73s 715😊
Is that permitted? Does anyone care?
A whole debate in itself.
@@CB-RADIO-UK Have you done a video on that debate, or ar you planning to make one?
*.... **#NO** OTHER THINGS TO "THINK" ABOUT.. IN "THIS" LIFE **#YOU** ALSO...*
Oh for heavens sake. Nothing like a bit of CB foolishness to make amusement. The SWR at the amplfiier will almost always NOT be the SWR at the CB Radio; and that's because of the transistor(s) in the path. The CB radio should never see "SWR" when connected to the amplifier provided the amplifier has a 50 ohm input impedance. It will always be 1:1 SWR no matter how terrible is the SWR at the antenna terminal.
So, always put your SWR meter on the output of the amplifier to see the SWR coming from the antenna. It is useful to briefly have it at the output of the CB and input of the amplifier to see if the amplifier is really 50 ohms input. That is to say, you should never, ever, see anything other than 1:1 perfect (nonexistent) SWR between CB and amplifier.
But of course, since doing all that is illegal anyway, who cares that you are doing it wrong.
Thanks Tom really appreciate the information in the comment.
@@CB-RADIO-UK A problem with Chinese amplifiers tends to be too low of input impedance. It isn't really much of a problem but it can produce erratic SWR measurements between radio and amplifier.
My enjoyment of this kind of channel is the bewilderment that some must feel on getting hundreds of totally contradictory comments. Do this, no don't do that; do something else. It's great. No, it's crap.
Interestingly, ham radio channels have similar conflicted advice where half have it more or less right, half have it pretty much wrong but it worked anyway because radios are pretty tolerant and the difference between 10 watts and 60 watts is 1 S-unit. It might make a difference but usually not.
That's why the new big thing in ham radio is little things; low power battery operated radios. It's like fishing with a light rod and line; it requires some skill and finesse and is more enjoyable. Anyone with a kilowatt can blast through the sky. That's easy. No skill.
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