Measuring Coaxial Cable Losses @ HF, VHF, and UHF frequencies.
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- Опубліковано 1 лис 2020
- The results are shocking! How much power is actually getting to your antenna? In this video, we'll find out.
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Great info. I was aware that cheaper coax had issues but never thought it was so severe in UHF/VHF.
Yeah I didn't know either. You read the specs and thats one thing, but to see it on a meter is another.
@@hamradiotube oh wow what coax shall i use then for getting nearly eberything to my antenna thats 15m away
Good stuff - an instant basic education of the ground rules of efficient installation in one vid - invaluable for a newbie like me still studying for his foundation/technician licence. Thanks.
Happy it helped. Good luck on your license. Thanks for watching.
Nice job helping us to understand the losses involved. Kind of surprising to me. Thank you.
Glad it was helpful!
Great video Mike. You posed the problem well and then let the data speak for itself. BTW, I read in one of the comments where a "balanced line" is compared to "coax feedline". That's sorta what I'm doing now a days. I'm using 50' of RG-8X coax on the WRC TIA 1000 and comparing it to a homebrew 40m speakerwire-dipole. Interesting stuff.
My earliest days of portable were spent making many a contact on a speaker wire antenna. They work great.
Great Show.
and you showed your results which hardly anyone does and they expect you to believe them.
Thank you very much.
I am Inspired now...
73.
Thank you very much!
Not that it'll do any good, but thanks for bringing the topic of loss up !
I have a friend that is sold on the free end spools of aluminum jacket coated Cable TV hardline !
After having a new Duel Band Omni placed on top of his tower, I ask him if he had the tower climber check the power squirting out the end, and I suggested it likely wasn't what he thought it to be !
Which began this back and forth between us.
I tried to explain that right from the jump, there is a mismatch from the 50 ohm components in the circuit, to the 75 ohm feedline !
Ending a best 1.5: 1 SWR !
Not that it is terrible, but he presumed 50 watts in, 50 watts out !
Granted the loses may be minimal, depending on one, the length of the run, and the frequency of interest, etc. etc. !!!
I got a real eye opener, when I decided to dip my toes into GMRS !
Obviously a few Mhz. North of the Amateurs UHF Band !
Where I was made quickly aware of the losses there, and the burden of cost, to try and beat those losses !
Where I discovered anything short of the diameter of a Fire hose, falls short !
Miserable.....!
This was a great topic as I am currently building a tower out in the cornfield behind my house about a 300Ft run. After calculating all the losses I was loosing close to 3Kw with LMR600 so I decided to upgrade to 7/8in HELIAX and the losses are now at 1.2KW. @27.400Mhz
Hi Mike! Thanks for this very usefull video. I work mostly portable on 20m with symmetric dipoles, so I do not lose much energy in my cable.
Ah, yes I have see you operating portable and you do a very fine job indeed!
@@hamradiotube 😃 Thanks. Hope to meet you on the air 😉
Thanks for doing this. I have read countless articles but have never seen a video of it actually being tested. I think I am going to buy MUCH better coax the next time I need it.
Glad it was helpful!
Great comparisons Mike! I really should upgrade my coax after seeing these results. 😂
Only if you want MORE POWER!!
Very helpful - thank you for making this!
You're very welcome!
Good video.
To double your range (same RX'ed power/voltage) you have to have 4 times the TX power (not 2 times), but that only applies to direct line-of-sight comms.
Normally the limiting factor will be the terrain (big lumps of dirt and rock getting in the way etc), in which case more TX power doesn't always help so much.
And if you are using the wrong coax, all that extra power is still going to be lost to heat.
Thanks for another great video Mike!
Thanks for watching!
Another great video! I have been running LMR400 for my LTE antennas running up to 1700 MHz. Love the bend radius though.
Yeah that’s some tough stuff for sure. Not my favorite coax to have to coil up.
@@hamradiotube yeah, we used to spec out that stiff cable and someone else connected it and ran it in our installation. After I retired and started playing radio and ran that stiff stuff I apologized got my technician who had to deal with this dumb engineer’s designs. Haha. I told him I had greater respect for what he did (I always appreciated him, just much more now). All the best!
Great visual Mike!!!
thank you
A lot of details. What do you suggest to use, RG 8x or LMR 240 or any other kind for CB? I will be needing about 60 feet. Thanks.
Great video and info. Thanks Mike!
Thank you buddy. Appreciate the comment.
Thanks for doing the experiment that I have always wanted to do myself! The other great coax question remains to be answered: When should coax be replaced? Ten years? 40 years? Never? I read lots of estimates. I have some 30-year old RG-213 coax that looks to be in good condition. But I've never seen or read of anyone doing quantitative measurements on very old line like you did for this coax.
Thats a great question that I don't have the answer too. I would say if it ain't broke, don't fix it. If you start having some kind of SWR or RFI issues, that might be a good indicator.
Is your SWR/Power meter connected at the antenna feed point or close to the radio? You could use the radio's built-in power meter or second SWR/Power meter connected close to the radio and another SWR/Power meter connected at the antenna feed point to check the loss in watts.
Great video. Now subscribed. I just fell victim to this by adding an additional 10 ft. of coax and a SO239 bulkhead adapter to “clean up” a cable run. Totally killed what previously was full quieting into a repeater 20 mi away. I can’t even reach it now. Live and learn.
I was getting ready to put in a bulkhead adapter. But now I won't.
Thanks for the sub. I'm surprised a bulkhead would completely kill your signal. Connectors will do "something" to your signal but are usually so small you would never notice it unless you had some precision instrument to detect it. I would look at a different piece of coax. I'm kinda suspecting one of the connectors could be shorted. I've had that happen to me on what I thought was a perfectly good piece of coax. Actually the grey coax in this video needed to have a connector replaced during filming. A coax I use all the time, and it had a short in it. It happens.
I am using a Stryker 955 HP , I need 100 ' of coax to the antenna . What is the best coax to use with that ?
Thanks for the very practical Video.I was about to buy some Dx Engineering 8x & 400MAX cable for loading my antenna 160 foot high on top of my high rise apartment running down by 14 floors to my shack .Just realised that there is no point running that much of cable for VHF even though it would drive a X300 but would rather use the DX400MAX for the HF multiband fan dipole .Changed my plan to have a smaller home brew vertical for VHF out of my balcony window.73's Ramesh VU2RKS
Yeah that would be a lot of wasted money and power not getting to the antenna for sure. Glad the video was helpful for you. Thanks for watching. 73
8X isnt any good unless its a foot max!
It's worth noting that feedline loss is a two-way street. It of course affects the transmit power being delivered to the antenna but it also attenuates the receive signal being delivered to the radio.
Although it's a bit out of scope for what K8MRD presents in this video, it might also be good to note that on HF a balanced feedline has much lower loss than even the best coax (especially when considering the loss due to SWR mismatch). Therefore a non-resonant doublet or loop can actually be much more efficient than a resonant coax-fed dipole.
Right you are and I completely skipped over that fact! I've not delved into balanced line yet, but yes, much lower losses. Thanks for watching.
Wait a minute....!
Whoa....Dud !
I think you accidentally discovered a never known magical coax length, that for once, doesn't rob you of RF, but instead,
" AMPLIFIES IT " !
From 100 watts in to a whopping 107 !
I'm guessing if you keep adding that magical length of coax, by splicing it together, you'll have a Kilowatt in no time !
Outstanding !
👍😉
😂🤣😂
Phenomenal ♡♡♡
This is exactly what I needed right now :)
🤜🏻👍🤛🏻
Thats why I made it lol!
Simple but effective demo.
Thanks Bob
Good video. I would like to point out a couple of additional things. Coaxial loss goes both ways. Not only does it affect the amount of transmit power getting to the antenna, it also affects receive signal strength at your transceiver. The quality of RG8X is all over the place. IMO, if you want RG8X size coax, pony up for Times Microwave LMR-240. For VHF/UHF work, if the length of the coax is going to be more than about 10 feet, use LMR-400. Yep, it's pricy, but worth it. 73 de WB4DW
Dually noted and something I failed to mention in this video. Thanks for the reply.
AT 440 MHZ, RG8X HAS ABOUT 135-140 OHMS OF CAPACITIVE REACTANCE. WHAT PART MIGHT TAT PLAY?
As to your comment, about winning some of the losses back, thru a gain antenna, and one you didn't mention, antenna height !
Which would be correct, but.....why not have it all, if you can ?
I dont comment much but i would like to say thanks for this video. Just use what we got to test
I stay away from cheap coax. Not all brands are the same.
Example, I have 2 100 FT rolls of RG-213. One has a nice tight
braded shield and then the center stranded conductor. The
other is double shielded. It starts with a foil type shielding,
then a tight braided shield the stranded center conductor.
Question: was the meter at the end of the cable just before
the dummy load or between the radio and the beginning
of the cable? Just curious. Nice video and very interesting
results. KF6EWO
Very good. Thanks a lot.👍☘️
My pleasure. Thanks for watching.
Great video 👍
Thank you very much
Absolutely excellent video describes the importance of coax so much, thank you Many can learn from this
I use LMR 400 for almost everything worth the money in the long run
So yes your antenna you made
It would have been better off with a 6-ft piece of coax and put it straight above your head
Actually I'm going to look and see if you have a video of making that antenna looks interesting
I came back to edit doesn't look like you have a video on your little antenna could you maybe do one and describe what you're doing with that ladder line
I'll tell you a real cool toy to play with one of the neatest things I bought in a long time is a nano HVNA very reasonably priced absolutely excellent on results
Great video! Thanks!
You bet!
Coax losses are well documented. RG8X comes in around 4.5dB at 2m and around 7 or so for 70cm per 100 ft. However, its down around 1dB or so of loss at HF frequencies. The real benefit of RG8X is that is much lighter and more flexible than something like LMR400 or even the RG213. Light and flexible doesn't matter a lot for a base station, but for portable or hiking it matters a lot. That said, if you're hiking, you're probably not needing 50-100 feet of the stuff either.
No matter what you're trying to do, just like radios and antennas, its important to do your research before buying/building a solution.
Indeed they are, but I thought it would be nice to see what that actually looks like on the meter. I usually use RG8X when I'm portable if I'm running 100 watts. I have some RG58U I think it is too. It's a little thinner and lighter, but it has a solid center which I don't like. I do a lot of hiking and ham radio too and use RG-316 for my QRP outings. Only about a 15-20' run into an EFHW. Works great. I have a love hate with the 316 though. Its nice and thing and light weight but it has a lot of memory and wants to kink when unrolling/rolling up. I use the over under method for all my wire and this is the only coax that gives me trouble. Doesn't stop me from making contacts all over the world though.
Hi Mike, Due to current finances and upcoming surgery, I am thinking of getting a Tri-Band or Dual Band Ed Fong antenna for the QTH since I don’t own this property and personal mobility. What are your thoughts on transmission line for the Ed Fong antenna and recommended length before getting beaten up on power loss from an Anytone 578UV Pro. Thank you! 73, Bill KC3RMV
Hi Bill. I used an Ed Fong antenna in my early ham career with 50' of RG8X and was able to hit repeaters about 10-15 miles away no problem. The antenna wasn't even up that high. Keep in mind that a large portion of your power will be lost in the coax. Obviously I don't really like to use RG8X on those frequencies and would highly recommend you get at least RG-213, or LMR-400 for any runs longer than what you might need for a car/mobile setup. As far as recommended lengths, thats going to depend on where you can put the antenna and how high up it will be. I use 100' of RG-213 to my VHF/UHF antennas. The shorter the better but you have to get it up. The RG213 and LMR400 have lower losses per 100' run.
Hi Mike, I've been loving your POTA videos and you have inspired me to get outside as soon as the weather breaks. I have some resonant wire antennas but I will have to purchase a run of coax to go portable. I haven't had much work due to the virus so I'd like to only purchase 1 run to start. You mentioned that your 50' run was your first, would you do it that way again, or would you have gone with 100'? I was thinking RG8X would give me the most flexibility to hoist wires and stuff, just wondering how much to get. Thanks for everything.
Depends on where your going to be connecting the antenna at. If I use my dipole up 43’ I’m gonna need 43’ of coax just to get up there, and then enough to get to my radio so I might need 100’. If your antenna connection is going to be close to the ground like a Wolf River Coils or PackTenna mini or efhw 50’ is plenty usually.
Oh and RG8X is plenty fine for HF.
@@hamradiotube Thank you for your insight Mike!
Thanks Mike…Where did you buy your workbench?
Harbor Freight
Good test on length vs frequency loss. I’m surprised how much loss you experience in the VHF/UHF bands.
Great stuff man.
Thanks for the visit
I have RG213 length 70 feet is the good for use on VHF and UHF please suggest me a cable I am new in HAM
Yes RG213 good
Hi Mike- what’s the best coax for vhf / uhf in your opinion?
The best stuff you can afford honestly. Most folks would use either RG-213 or LMR-400.
Great video. This is why I run LMR 400.
Good choice!
K7GF - LMR400 is pricey and it’s more difficult to work with (bigger bend radius). They have their pros and cons. For example, a short length of RG-8X is great to stuff in the backpack and hike with (SOTA). Running QRP at home I’d definitely prefer LMR400 - but my wallet said, “Go with the RG-213/U”.
@@dougyoes Hi why not use LMR 240 for shorter lengths instead of rg8x? Also up to what short length would you use rg8x up to? I am looking to buy the slim jim j pole from N9TAX, I am new to radio so would like to know your opinion if I should use the 16' rg58 cable it comes with or just buy the antenna and use 33' of lmr 240 (found a good deal on it). I will be using it for backpacking/general preparedness situation. So one antenna will be for GMRS and the other for 2m/70cm 5 watt radios.
hi, good video well explained,i hope to do a test on the Gainmaster 5/8 wave and 25 meters 213 u coax cable. I have 2 exact swr/power meters ,just waiting for some good weather ,thanks from Rotterdam.
Right on. A gain antenna would be how to get that power back.
So, what is the best type and brand of cable for vhf/uhf radio?
I don't know. I only have 3 types of coax. The best I have is the RG213. Others will tell you LMR-400 while others will tell you LMR-600. Get the best you can afford.
I was in same boat, till I started my project to push my antenna 10 ft higher. So I decided to upgrade coax. I wish I could attach my side by side of rg8x next to dxe-400max!
I can only imagine.
It was not a little experiment, it was a brilliant experiment..i was planning to put up a 2m Antenna with RG8x but not anymore, i do have RG213 so definitely going to use that now after watching the video..I have another question, if at CW keydown my IC7300 power meter is showing 70 watts where as 100nwatts is selected....how accurate is this in your opinion ?...TNX
Glad to save you from using the wrong coax. As far as your 7300, I would assume your swr is somewhere near terrible if you are on 100% and you are only putting out 70. The radio will pull back on the power when presented with too high an SWR. Might want to check your antenna.
@@hamradiotube that is with the tunner... without tunner its definitely more, its a Multiband Doublet antenna, so inherently it gives high SWR.
Thanks mike!
Any time!
What if anything would have happened, if each comparison was made using the proper multiplier in length, to provide a transformer of sorts, showing 50 ohms at each end of the Coax ?
Seems the transfer of power would be near perfect, given the inefficiencies of the materials used ?
I use 213 as much as I can. Have you looked at RG-400, guess it would be great its just money. like your comments .
Have 817 and g90 want to go to the woods. which one would you use. sell both and get 991
73
No way would I buy a 991! Eww. My neighbor has one (991A actually) and I'm not a fan.
What is the best for high power?
Depends on the frequencies, but I'm told get the best you can afford. It starts to get pretty expensive once you go past LMR-400.
Hi Mike. What model is that MFJ meter?
MFJ-849
Yes, the MFJ-849
Thanks guys. 73.
@@kevingoshe4371 never in stock
good test rg 8x and rg213 is suted the best 4 hf band operations 4 whf uhf rg400 lmr400 lmr600 lmr 900 or lmr1000 that is 4 long runs above 100feet
Do you have any lmr400?
I do not. The 213 is the best I have.
Yup...really important when your on CB and limited to 4 watts. Thats why a Super Penetrator with a short feed line is the best 'round the Ozarks. Thanx. Green Eagle KTD0907 Spfd., Mo.
Cables are no longer standardized to the same specs for the same RG type number stamped on the cable. The RG8X tested, like RG213/U any of us have, might be nowhere near the results in the video.
Cables we buy might be, and probably are, either better or worse. I've purchased and I've tested some absolute junk RG8X, and likewise some very good RG8X. For example someone recently gifted me some RG8X jumpers made with cable from a very well-known cable vendor. That "premium" cable was actually 54-ohm, which rendered it useless on test benches (but probably okay for antennas).
Good RG8X is perfectly fine at HF for moderate runs like 100 ft or so, longer at lower frequencies and shorter at higher, and good RG8X will take a ton of power. As a point of reference my test bench still uses an RG8X jumper I made in 1983. That cable was used on test benches testing 1500W+ amplifiers, one after another, for years. It is just as good on a real VNA today as it was in 1983.
On the other hand I have some private label RG8X from a well-know long time wire vendor that went completely bad in about 5 -6 years indoors on the reel! The dielectric became brittle and developed cracks.
Never take one test or one sample as the way all cables are, especially unknown cables.
Great comparison, thanks. Next time maybe test some LMR-400 and have nothing but quality coax at all the same lengths? I think most HAM's know not to buy coax from eBay or Amazon, if they want high quality.
I bet that Chinese Amazon RG8x is junk copper coated Aluminum. Good true oxy free Cu from ABR is going to lose far less power for sure. the lower the frequency the less the loss which is how it works for all these cables.
Good test. Thanks for showing the newer hams who do not take this into consideration! To be honest if I were running a serious VHF antenna installation on my home I would run LMR-400 or better yet LMR 600.
The amazon stuff isn't the greatest thats for sure. I'm happy with my Tram coax though. If I were serious about VHF I'd prob have 400 as well, I just don't really get on those higher freq's too much to bother.
Hi Mike K8MRD. Great video man, just goes to show that the coax losses are a real pain in the butt specially on UHF/VHF.
Just wondering on the effect of cutting your cable in half wavelength multiples. There are several videos on UA-cam that says inductance and capacitance varies inside that half wavelength piece of coax and cutting your cable in half wavelength multiples would minimize its effects and therefore maximize your transmission power. I've incorporated that method whenever I cut coax cables for my own or a friend's setup but not having the right tools to prove it works just makes it about 90% accurate and not 100% in my mind if you know what I mean.
Thanks and 73. 4G1FBL from the Philippines.
Thanks for watching. I've not heard that about coax as a whole. I know with end fed antennas the length of the coax might matter, but not always. Thats interesting.
@@hamradiotube cutting your coax in half wavelength multiples reduces the inductance and capacitance in it according to the theory and you eventually end up with the required total length for a particular frequency. Here's the best example (and explanation) I could find.
ua-cam.com/video/Z2lxv6F8fvA/v-deo.html
I would have liked to see comparison to LMR400 at 50 and 100 feet.....
Me too, but I don't own any.
I hope we can somehow do impedance matching to mitigate transmission line losses.
Even a perfect impedance match will suffer losses.
Everything in this video was 50 ohms. Impedance matching would be more on the antenna side of things. We're almost always (except for a few unique circumstances) going to use a 50ohm coax. However, if we are matching impedances with the antenna, say a 9:1 unun, there is always going to be some loss in that transformation. There is always a compromise to be made somewhere.
Jim W6LG did exactly the same test about 5 years ago on his youtube channel.
Would you use RG8x for receive only, like for a scanner or SDRplay ?
KN6AAH
On Hf sure. Losses work both ways with coax though. So if you use 8x on vhf/uhf your received signal wouldn’t be as much as with a better coax.
Surprised he didn't use any LMR coax.
Same goes for mobile, cut off that extra cable and don't think about using RG-174 (smaller than RG-58) cable. Also, this is why the Satellite and DX guys use tower mounted preamps, as every Db counts in weak signal work.
Yeah this had me thinking about the coax in my mobile as well. They all seem to use thin, lossy coax as well.
@K8MRD you forgot to mention that not only your TX power but also your RX power has the same losses,
so if you try to work a distant station that is not all that strong to begin with you only get 16.46% of that weak signal (using your RG8X example
I think its safe to say, your DX station is not workable ;-)
73.
PD0HOF
You are correct. I would still say he's workable 16.46% of the time though :)
Hows about trying LDF5-50 and Formula Zero F Zero is very good at a realistic price unlike the M&P stuff
Send me some :)
@@hamradiotube Probably fraction of the price ther compared to here but F-Zero is about the same cost as RG213 but what a difference amazing .
Mike: At UHF and to an extent VHF, every dB counts. Most serious VHF/UHF Weak Signal enthusiasts use something like LMR-600 or Hardline. Normally they use N-Connectors because PL-259’s are very lossy at those frequencies. You always want high quality, low loss coax or hardline. Your cheaper coax will not have nearly enough braid to be usable at those frequencies. LMR-400 or 9913 would be a much better choice. At these frequencies it is all about “System Loss” and getting as much power as you can to your high gain antenna. But if you are talking about taking something portable, you have to balance weight and gain.
It all started with building a portable antenna. I am the farthest thing from a series vhf/uhf guy so I don't see myself getting any super fancy coax any time soon. I'm 99.9999999% of the time on HF. Still, I though this experiment was interesting to see just how much you lose out of 2 of the more common coax you see. Plus, I doubt a new ham is going to invest in such serious coax so its good to show these kinds of things. Thanks for watching and thanks for the input. 73
@@hamradiotube - Mike, I totally understand what you are trying to do. It always pays to have good low loss coax with a lot of braid in the shield. You can take the same type of coax, like RG-8X from 4 different manufacturers and the shielding can be vastly different. Always get good coax from someone like DX Enginerring and you won’t go wrong. For POTA activations I use LMR-400 from DX Engineering with my FT-891 and WRC and it works great. Great video, keep it up!
@@n5pa Wow I'm not taking lmr400 for pota. My pack already weighs enough! The coax I use from Tram is 95% shielded.
@@hamradiotube lmr-400 is a waste for HF. (10m and 6m notwithstanding)
Have 100ft of Lmr400 at 1kw very good transmission on 40 and 20m.
I would like both of those things. In due time.
Check out ebay prices
Your vhf/uhf results are an object lesson in what a loss in dB per 100 feet really means. Remember -3dB is half your power down the tubes. And in UHF moon bounce you quickly learn that having your receive converter/ amplifiers, etc. at the antenna feed point is necessary.
And boy does it go quick! I wonder if there is a preamp you could put at the feed point of the antenna to boost the signal for moon bounce? I've not experimented with that mode.
Try the rg400 on vhf and uhf for mobile
I'm not familiar with RG400. That can fit through a door or a trunk for mobile??
@@hamradiotube RG400 is about the same size as RG58, it’s a dual screen Teflon insulated coax with silver plated conductors. It has lower loss than RG58 but its a little less flexible. Another alternative is RG142 which looks similar to RG400 but has a solid rather than stranded centre conductor and a bit less loss but is also less flexible again.
Hi Mike, I hope your using the DX engineering coax n stuff. It'll be a great show
Why not ABR Industries coax N stuff
Why not just the coax I have?
@@hamradiotube just razing.
I'm sure you will use a good cables, looking forward to your great show.
@@hamradiotube you didn’t say “n stuff”
Running an amp magnifies the losses even more.
Yup, but also increases your odds of magic smoke.
GREAT VID. JUST WONDERING, AT 440 MHZ, RG8X HAS ABOUT 135-140 OHMS OF CAPACITIVE REACTANCE. WHAT PART MIGHT THAT PLAY?
As to Chinese manufactured coax's, it is my understanding that they all come out of one or two of the same manufacturers ?
Tram and Browning two big offender's !
I believe typically, you will see much better spec's on these coax's, the closer you come to 11 meters !
Or RG 400?
That's what I use for everything.
RG400?
@@hamradiotube Silver angel hair
www.awcwire.com/productspec.aspx?id=rg400-coaxial-cable
www.dxengineering.com/parts/dxe-rg400-ctl
its also a two way street. cant hear well will crap coax cable. i use LMR-400-UF(Ultra Flex). bellscb.com/products/accessories/LMR-400_coax.htm
indeed it is. LMR 400 is great for sure.
Good practical demonstration. Incoming signal losses also, probably why I tend to stay on HF only! KV5R has a great website, with a loss calculator & info. Keep up the good work, thanks again. 73 de GW4OKT
Thanks for watching. Yes I failed to mention the incoming part of it. I stay on HF because that's where all the cool people hang out ;)
@@hamradiotube Yep-that's were the POTA action is! :-)
@@g4okt Exactly!
Good experiment. Thank you, de 9W2UPI.
Thank you!
Seems like a job for a NanoVNA!
I had one of those and gave it away 10 minutes after opening it. Didn't like it at all. Too fidgety for me.
LMR-400?
I don't have any.
@@hamradiotube I am waiting for some, around 24'. Assuming you are connecting the radio to the coax, then the meter at the end of the coax, and between the dummy load. Maybe coax in same room? Will try. Thanks.
@@k2icc Yes, the meter would be at the end of the coax simulating the antenna feed point. The dummy load was connected with about 2' of RG8X after the meter.
Try M&P hyperflex 10 and then try to improve on it.
??? When I first saw RG8X I thought this is cheap. So I went to a coax loss chart. Then I said what freaking idiot would buy a freaking resister to put between their antenna and radio. Seriously!!!! I see people buying that crap all the time!!!! The worse part is they buy 50 foot, which is the WORST possible length a crappy coax should be bought at. At 50 foot it perfectly hits the highest SWRs at basally every ham band. People spend good money to buy a quality radio and tuner, then screw up buying the very thing that makes their good purchases basically worthless.
P.S. RG8X at 50 foot on UHF your output if everything else is right is about 25%. That means 3/4 of your power is ate up.
Here is a great article to compliment your tests. www.electronics-notes.com/articles/antennas-propagation/rf-feeders-transmission-lines/rf-coaxial-feeder-cable.php
Good stuff, thanks for sharing. 73
#LMR400 FTW
I don't have any :(
I just bought 200 feet of 24600 for the tower. My ass is still chapped.
I don't know what that is but all those numbers in it cant be cheap.
@@hamradiotube DESCRIPTION:
Flexible alternative to ½” Hardline (Helix©)
UV Resistant, Direct Burial, Polyethylene Black Jacket.
Gas Injected Foam Polyethylene Dielectric VP: 87%
RoHS Compliant.
Overall Diameter: .590?
Nominal Attenuation-per 100ft/Power Rating(kW)/Efficiently%
0.5dB @ 50MHz/4.24kW/88.2% E.
1.0dB @ 150MHz/2.41kW/80.1% E.
1.7dB @ 450MHz/1.35kW/67.3% E.
2.5dB @ 900MHz/0.93kW/56.2% E.
ABR 24600 is a low loss high-performance cable. An alternative to CommScope® WBC-600, Andrew® CNT-600 coax cable, Belden®, TerraWave TWS-600 and Times Microwave Systems® LMR-600.
Copy and paste is a wonderful thing.
@@1958johndeere620 Holy crap that's awesome!
@@hamradiotube I spent 3 years building a 70 foot fold over rohn 25G and figured I would get the most out the door I could. I use the 600 cable for a A13B2 beam, and 1 for my Diamond X300 both at 75ish feet. For all my HF needs the ABR 25400 is very good cable.
Esh My RG8X came from Walmart
Well I've been buying it from the wrong place this whole time!
@@hamradiotube No I have but for now it gets me out
Don't buy cheap coax
Very true.
Great video! Thanks!
You're welcome!
I have thought about this topic and your video brought out the issues! Well done as always!