Being that the Feed point impedance for a Half wave Dipole, is 73 ohms, I decided to build an antenna for Forty meters, using RG - 11, 75 ohm Quad shield ! Best Dipole I have ever made ! And I believe it is the quietest due to the Quad shielding ! Try it, you'll like it ! 👍😉
@@Skullfocher I believe I began with a 100 foot length, then bought a splice connector, and added until I got the length needed to get in the shack ! Plus an adapter to PL 259. Don't mean to sound vague but it's been awhile ! GOOD LUCK !
I've been useing RG 11 75 ohm coax for years . Very low loss I use a one to one balun at the feed point of my vertical anteena. which brings the ohms to 55 at my amp .Talk all over the world on HF .. Its stiff but not bad just run it to my watt meter and use military grade 213 6 foot jumpers from my amp and radio.. No problems for over 10 years.,
I have a buddy in Canada who uses 75 ohm RG-6 quad for a lot of his installs. If you find the velocity factor vs the wavelength impedance at frequency, you can cut the right length to match 50 ohms and not even need a transformer.
I do want to add that although my home station is going to all hardline, I will say that the best coax for an application really depends on a couple factors: frequency, output power level, durability, ease of use, and most importantly, cost. If all you can afford is a 25' jumper of RG8X, then get it. Something is always better than nothing. But if you want things like performance, near-zero loss, power handling, interference and noise rejection, or simply longer runs to your antennas, then you have to start figuring out what you need to accomplish your desired results. As for me, I have two towers one for VHF/UHF, the other for HF. I also operate mainly DX including satellite, weak signal, and EME. Considering the length I have to run and the signal loss due to distance, loss is a HUGE factor for me. On 23 cm a 75 ft run of anything half inch or smaller the loss is so much that it's become necessary to get the largest hard line that I can reasonably afford. 75 feet of 7/8" heliax will easily set you back $400-$700 depending on whether or not you have access to the tools needed to install it. The prep tool alone cost me $400. The connectors are about $40 each. It's expensive, but my goal is to minimize loss as much as possible. Of course 7/8" on 80 or 160 meters is complete overkill, but I also want to minimize the noise on those bands, plus run 1000 watts. So even though loss is not a big deal, melting my cable isn't an option either. To make a long story short: get the best cable you can afford. RG-213 is a good baseline for stations with runs under 50 feet for most applications. Slightly cheaper than LMR-400 with about 0.1 dB difference up to 150 MHz. I would avoid RG-58 though at all cost. Lol 73, K7AXA
I see everyone saying U/V go big or go home. HF small is okay! I use LMR400 for all permanent installations. I also use LMR 400 in the field for U/V. I do use RG316 and RG8 for HF. And for short runs like 15 feet (like to the slimjim slung into a tree) on U/V I'll use RG8.
HF RG8x, VHF/UHF is LMR400. LMR400 has the disadvantage of using CCA core, this is great for weight and performance but not if you want to flex it. I won't use LMR400 for anything but long term setups. LMF400UF (ultraflex) is a stranded copper core, it has higher losses than LMR400 but is still better than RG213 and RG8 (let alone RG8x) it better for field use. When you are HF comparing
For some cases LMR 400 is great coax. I have found problems with it and has nothing to do with loss in the cable. It has to do with strong signals and aluminum foil and tinned copper braid. some use AL braid and AL foil . The dissimilar metals on the shield cause a problem with RF signals with acting like a diode detector and causing heterodyne interference and can cause harmonics . Some times this does not happen but it does a lot when multi signals travel in same coax like in a repeater or near a broadcast transmitter. Them the mixing of signals happen in the shield . last year I had to fix a GMRS repeater that took near buy lightning strike . It lost range buy a lot. I noticed they used times microwave LMR 400 cable . The cable was not real long due to roof mounted shack . only 45 ft from repeater to antenna. After some testing the coax was loosey and GDT protector did it's job and nearly shorted. High SWR . Went with all new coax. Even the jumpers from duplexer to repeater . ant was fine. 11DB gain commercial UHF antenna . Went with M & P coax. Hyper flex 10 Sierra FT8 with N connectors . New short jumpers . Ned GDT Polyphaser N protector. after done worked so good it was better than ever. The wired static that would come in time to time went away. I could have just replaced the GDT but I knew better with that coax at a repeater cite. in fact the FCC does not allow that type of coax. For the AVG ham you may never see this problem. I have learned things in broadcast . M & P made in italy is all copper. copper foil and braid . Has better spec than LMR . The only thing better is hard line. ABR in Texas makes all copper coax as well and the best in the USA . The outher trouble is Aluminum has different villosity factor than copper. When getting to broadcast power levels makes a difference. my own radio use is mostly M & P -POTAFLEX 7 coax. I have ABR 400T jumpers and chokes as well. That RG 400 coax. DX commander has a very long run and uses M & P coax to cut loss . RG 8X is great for them 3 ft jumpers for HF . I have some I use for POTA . I replace with RG 400 or POTA FLEX 6 or 7 for my short jumpers now, Last longer and rated UHF . Just read them data sheets on coax and pick what works. 73
When I was in telecom, the standard was LMR400 for runs up to 100' up to ~950 MHz (SCADA remote radios). Anything over 100' got 7/8" hardline. SCADA masters (~950 MHz), TGB base stations (~900 MHz), and m/w (2.4 GHz and 5.8 GHz) was going to get 1 5/8" hardline regardless of the install. I left the telecom group and I know they're doing some 11 GHz now but I don't know what size hard line they're using. Personally, I run LMR400 on HF from the balun at the bottom of my mast to the lightning protection just before it enters the house, another 25' LMR400 jumper to a coax switch, and then a 6' RG-8X jumper to the back of the tuner. I have about 75' from the base of the mast to the coax switch but I also like to run QRP on CW and digital so every dB counts. For VHF/UHF, no question - always LMR400. Plus, dB means *nothing* without a reference. For example, I'm used to dealing with dBm - a decibel referenced to a milliwatt (mW). I know 37 dBm is about 5 W, 30 dBm is about 1 W, and 27 dBm is about 0.5 W.
There are several db calculators, as well as coax loss calculators on the interweb. To me the ~1/4th S-Unit difference between the coax's @25' isn't enough to obsess about as its indiscernible at the other station Except Possibly under very weak signal conditions. Get the best coax you can afford it at the time, BUT don't obsess about it if you have the cheaper stuff. ANY signal is better than being off the air. Some may be unable to stop obsessing about any amount of loss, so YMMV. 73 mike 🍺🍻 (If you want a better signal on 2M get your antenna above the tree top level.)
Thanks for putting this together. I know what I’m asking for Christmas. Does this mean all your jumper cables need to be lmr 400 as well for the antenna tuner, etc?
heh, 2m magmount stuck to an old steel firepit upside down in the attic. super low Q factor, public safety, broadcast FM and ham. great question! dumb answer, I know.
A friend of mine brought to my attention that My Voice was heard on this video, keep up the good work LMR 400 for the win at VHF in UHF like you said buy once cry once.
There are some cheap alternatives to LMR400 that while they don't hold a candle to LMR they're better than RG8x or RG58. If you're on a budget like me, wilson 400 is okayish. Like I said, LMR is better, but wilson will do the job.
dB are easy. Just go learn. a 3db loss means you lost half your power. A 10dB loss means only 10% of the power comes out. The loss tables apply to an antenna with exactly 1:1 SWR of your antenna has a greater SWR the loss will be more. LMR 400 should be used for modest runs on VHF and below. LMR 600 is more appropriate for modest runs on 70 cm. RG8x Ok for short runs on HF using low power. RG8x jumpers are ok in the shack and I use LMR240UF for portable HF (< 50 ft.) I use LMR400 (or equivalent) in my station except for 70CM and above where even larger cable is used. for 70cm and above use N connectors. An antenna analyzer like those sold by RigExpert or an NanoVNA can measure. I have a piece of Chinese RG174 (real skinny). Loss tables indicate 9dB/ 100 ft but measurements at 450MhZ were found to be 33dB per 100ft. I bought the cable to illustrate loss measurements. Try your experiment using 70cm.
It doesn't help that there are many pieces of coex out there mocked as LMR400 or equivalent, and many other designations, which are sold on the likes of Amazon, banggood, Temu, eBay, and many other online sellers which are nowhere near the stated standard and how complete garbage.
@@SkullfocherYeah, PL-259 & SO-239 are sometimes called UHF connectors, but what was considered UHF was a much lower frequency when these connectors were first designed.
@@rickgilbrt Yes I know that. Did you know though that at higher UHF frequencies the pin of the connector will become reactive and act as an antenna? Thus causing your swr to radiply increase. These are why most connectors designed for frequencies above 300 MHz typically use type N connectors or DIN.
@@rickgilbrt originally the UHF band was considered anything over 30 MHz until the reclassification of the frequency spectrum by the ITU between 1937 and 1942. But all that has nothing to do with my original statement. On "current" UHF frequencies, PL-259 and SO-239 (traditionally called UHF) connectors cause reactance and the higher in frequency you go, become more resonant, which is why they are not used for those frequencies. That was my point. It had nothing to do with nomenclature.
@@Skullfocher I understand that and wasn't criticizing your comment. I just think it's interesting that we sometimes still use outdated nomenclature - and accept that manufacturers sell outdated hardware. How many VHF/UHF mobile radios by "the majors" are sold with SO-239 connections? I don't know any that have anything else. As a new ham ten years ago, it was confusing to see "UHF" connectors on mobiles, and then read that the SO-239/PL-259 connector so are not actually good for UHF frequencies.
So a old school 10 to 12 meter operator operating 100' to antennas with rg8x 100' will mathematically be 100% loss !!!!!?? Contemplating 213 on these runs I question the ocean jumps i get daily?? If 100% loss should be 0 at base of antenna
Heh, I thought that too, but think of it as walking half the distance to a wall, repeatedly. You never make it to the wall, but you get really close. Logarithmic approach to zero.
I tried for my ticket WAYNACK mid late 70s utilizing an ELMER who silent keyed as i hit 15 wds min onn keywork you know when code was REQUIRED NOW ONLY TECHNICAL QUESTIONS NEEDED AND KEY MORE OR LESS HAS DROPPED BEHIND uses my practice unit was yaesu ft101e Turning itt to 10 11 meter without am filter great radio but tight transmit recv locals had hard time understanding on am
Next test, same but on 10, 20 and 40 meters. Lazy minds must be in the know! BTW, the myth is the the length of coax in the mobile IS important... So they claim. First find out who "they" then see if they are correct.
Being that the Feed point impedance for a Half wave Dipole, is 73 ohms, I decided to build an antenna for Forty meters, using RG - 11, 75 ohm Quad shield !
Best Dipole I have ever made !
And I believe it is the quietest due to the Quad shielding !
Try it, you'll like it !
👍😉
I've wanted to try that. Can I ask what length of cable you used?
@@Skullfocher
I believe I began with a 100 foot length, then bought a splice connector, and added until I got the length needed to get in the shack !
Plus an adapter to PL 259.
Don't mean to sound vague but it's been awhile !
GOOD LUCK !
DB are easy. 3db is double in gain, and half in loss. 1w with 3db gain is 2w, and 1w with 3db loss is .5w.
Ive upgraded most my outdoor runs to LMR600 ! Overkill in some cases but satisfying!
I've been useing RG 11 75 ohm coax for years . Very low loss I use a one to one balun at the feed point of my vertical anteena. which brings the ohms to 55 at my amp .Talk all over the world on HF .. Its stiff but not bad just run it to my watt meter and use military grade 213 6 foot jumpers from my amp and radio.. No problems for over 10 years.,
I have a buddy in Canada who uses 75 ohm RG-6 quad for a lot of his installs. If you find the velocity factor vs the wavelength impedance at frequency, you can cut the right length to match 50 ohms and not even need a transformer.
I do want to add that although my home station is going to all hardline, I will say that the best coax for an application really depends on a couple factors: frequency, output power level, durability, ease of use, and most importantly, cost. If all you can afford is a 25' jumper of RG8X, then get it. Something is always better than nothing. But if you want things like performance, near-zero loss, power handling, interference and noise rejection, or simply longer runs to your antennas, then you have to start figuring out what you need to accomplish your desired results. As for me, I have two towers one for VHF/UHF, the other for HF. I also operate mainly DX including satellite, weak signal, and EME. Considering the length I have to run and the signal loss due to distance, loss is a HUGE factor for me. On 23 cm a 75 ft run of anything half inch or smaller the loss is so much that it's become necessary to get the largest hard line that I can reasonably afford. 75 feet of 7/8" heliax will easily set you back $400-$700 depending on whether or not you have access to the tools needed to install it. The prep tool alone cost me $400. The connectors are about $40 each. It's expensive, but my goal is to minimize loss as much as possible. Of course 7/8" on 80 or 160 meters is complete overkill, but I also want to minimize the noise on those bands, plus run 1000 watts. So even though loss is not a big deal, melting my cable isn't an option either.
To make a long story short: get the best cable you can afford. RG-213 is a good baseline for stations with runs under 50 feet for most applications. Slightly cheaper than LMR-400 with about 0.1 dB difference up to 150 MHz.
I would avoid RG-58 though at all cost. Lol
73, K7AXA
I see everyone saying U/V go big or go home. HF small is okay! I use LMR400 for all permanent installations. I also use LMR 400 in the field for U/V. I do use RG316 and RG8 for HF. And for short runs like 15 feet (like to the slimjim slung into a tree) on U/V I'll use RG8.
Buy for vhf, 7/8 hardline. The Messi Paloni 13 Hyperflex is not that bad compared to 1/2 or 5/8 hardline.
Amen!! Might I also add Andrew or Commscope.
HF RG8x, VHF/UHF is LMR400.
LMR400 has the disadvantage of using CCA core, this is great for weight and performance but not if you want to flex it. I won't use LMR400 for anything but long term setups. LMF400UF (ultraflex) is a stranded copper core, it has higher losses than LMR400 but is still better than RG213 and RG8 (let alone RG8x) it better for field use.
When you are HF comparing
Don't write off differences in brands. I use Messi and Paoloni. Size depends on application. Frequency, power, length. Their connectors are super!
VHF and UHF I use LMR400, RG-8X for HF.
For UHF I use AVA5-50 or LMR-600, and LDF4-50A for everything below 150 MHz.
For some cases LMR 400 is great coax. I have found problems with it and has nothing to do with loss in the cable. It has to do with strong signals and aluminum foil and tinned copper braid. some use AL braid and AL foil . The dissimilar metals on the shield cause a problem with RF signals with acting like a diode detector and causing heterodyne interference and can cause harmonics . Some times this does not happen but it does a lot when multi signals travel in same coax like in a repeater or near a broadcast transmitter. Them the mixing of signals happen in the shield . last year I had to fix a GMRS repeater that took near buy lightning strike . It lost range buy a lot. I noticed they used times microwave LMR 400 cable . The cable was not real long due to roof mounted shack . only 45 ft from repeater to antenna. After some testing the coax was loosey and GDT protector did it's job and nearly shorted. High SWR . Went with all new coax. Even the jumpers from duplexer to repeater . ant was fine. 11DB gain commercial UHF antenna . Went with M & P coax. Hyper flex 10 Sierra FT8 with N connectors . New short jumpers . Ned GDT Polyphaser N protector. after done worked so good it was better than ever. The wired static that would come in time to time went away. I could have just replaced the GDT but I knew better with that coax at a repeater cite. in fact the FCC does not allow that type of coax. For the AVG ham you may never see this problem. I have learned things in broadcast . M & P made in italy is all copper. copper foil and braid . Has better spec than LMR . The only thing better is hard line. ABR in Texas makes all copper coax as well and the best in the USA . The outher trouble is Aluminum has different villosity factor than copper. When getting to broadcast power levels makes a difference. my own radio use is mostly M & P -POTAFLEX 7 coax. I have ABR 400T jumpers and chokes as well. That RG 400 coax. DX commander has a very long run and uses M & P coax to cut loss . RG 8X is great for them 3 ft jumpers for HF . I have some I use for POTA . I replace with RG 400 or POTA FLEX 6 or 7 for my short jumpers now, Last longer and rated UHF . Just read them data sheets on coax and pick what works. 73
When I was in telecom, the standard was LMR400 for runs up to 100' up to ~950 MHz (SCADA remote radios). Anything over 100' got 7/8" hardline. SCADA masters (~950 MHz), TGB base stations (~900 MHz), and m/w (2.4 GHz and 5.8 GHz) was going to get 1 5/8" hardline regardless of the install. I left the telecom group and I know they're doing some 11 GHz now but I don't know what size hard line they're using.
Personally, I run LMR400 on HF from the balun at the bottom of my mast to the lightning protection just before it enters the house, another 25' LMR400 jumper to a coax switch, and then a 6' RG-8X jumper to the back of the tuner. I have about 75' from the base of the mast to the coax switch but I also like to run QRP on CW and digital so every dB counts. For VHF/UHF, no question - always LMR400.
Plus, dB means *nothing* without a reference. For example, I'm used to dealing with dBm - a decibel referenced to a milliwatt (mW). I know 37 dBm is about 5 W, 30 dBm is about 1 W, and 27 dBm is about 0.5 W.
@@joelblack6174 Around here most everything above 5GHZ gets waveguide.
I just picked up 300’ of bulk M&P Hyperflex 5 for $189 delivered (ordered direct from M&P). Investing in quality low-loss coax is a no-brainer!
There are several db calculators, as well as coax loss calculators on the interweb. To me the ~1/4th S-Unit difference between the coax's @25' isn't enough to obsess about as its indiscernible at the other station Except Possibly under very weak signal conditions. Get the best coax you can afford it at the time, BUT don't obsess about it if you have the cheaper stuff. ANY signal is better than being off the air.
Some may be unable to stop obsessing about any amount of loss, so YMMV.
73 mike 🍺🍻
(If you want a better signal on 2M get your antenna above the tree top level.)
I use LMR-240 in a lot of jobs its loss is between 8x and lmr-400 about equal to RG 213 or the older RG 8u and is a better price than lmr 400. K6DCH
agreed, the only real downside is the stiffness? solid core?
Times microwave, lmr240 if is stranded
Uf
I use a 5' jumper of LMR-240 from my FT-818 to a 23 cm transverter. It's pretty stout stuff for short runs. I will probably use 240 in my mobile rig.
Love your format Craig keep the bumper music coming and of course the video's.
Vk5kov
I have been using LMR-400 with one 8x for my HF antenna.
RG8X is great for HF, not so much for VHF and event worst for UHF
Maybe for a mobile installation and 100 watts. But in reality RG8x really isn't that great.
Thanks for putting this together. I know what I’m asking for Christmas. Does this mean all your jumper cables need to be lmr 400 as well for the antenna tuner, etc?
You're going to need a big stocking. The loss is linear, per foot... I wouldn't worry about upgrading jumpers.
I use LMR-400 UF stranded. its flexible. the solid core is not flexible. im enjoying it very much.
I use RG 213 for VHF/Uhf and HF….It’s more flexible than lmr 400 and not as lossy as Rg8. So it’s a good all around coaxial for amateur radio
Went to lmr 400 never going back. Rg8x is fine for HF I don't think you will really notice the difference.
I went to lmr400 and get much better reception and transmit. Hands down a better choice. I'm running the rt95 25 watt dual band
Hi, great channel. I have a random question. Which antenna do you use for your RSP1B? Thanks
heh, 2m magmount stuck to an old steel firepit upside down in the attic. super low Q factor, public safety, broadcast FM and ham. great question! dumb answer, I know.
Thanks!
A friend of mine brought to my attention that My Voice was heard on this video, keep up the good work LMR 400 for the win at VHF in UHF like you said buy once cry once.
w00t! thanks for the support!
sorry if you're accidentally famous! see you on the w6ek net
1 S-Unit = 6dB
I use LMR 400 for any run over 5 feet. Bite the bullet and go quality. KB3NG
Why LMR-400? Half inch heliax has half the loss, almost as flexible, and comparable price.
There are some cheap alternatives to LMR400 that while they don't hold a candle to LMR they're better than RG8x or RG58. If you're on a budget like me, wilson 400 is okayish. Like I said, LMR is better, but wilson will do the job.
dB are easy. Just go learn. a 3db loss means you lost half your power. A 10dB loss means only 10% of the power comes out. The loss tables apply to an antenna with exactly 1:1 SWR of your antenna has a greater SWR the loss will be more. LMR 400 should be used for modest runs on VHF and below. LMR 600 is more appropriate for modest runs on 70 cm. RG8x Ok for short runs on HF using low power. RG8x jumpers are ok in the shack and I use LMR240UF for portable HF (< 50 ft.) I use LMR400 (or equivalent) in my station except for 70CM and above where even larger cable is used. for 70cm and above use N connectors. An antenna analyzer like those sold by RigExpert or an NanoVNA can measure. I have a piece of Chinese RG174 (real skinny). Loss tables indicate 9dB/ 100 ft but measurements at 450MhZ were found to be 33dB per 100ft. I bought the cable to illustrate loss measurements. Try your experiment using 70cm.
Sorry but I've upgraded to AVA5-50 with LDF4-50A jumpers.
It doesn't help that there are many pieces of coex out there mocked as LMR400 or equivalent, and many other designations, which are sold on the likes of Amazon, banggood, Temu, eBay, and many other online sellers which are nowhere near the stated standard and how complete garbage.
7/8" Hardline on 10 meters
If you replace those PL-259/SO-239 connectors with N type connectors you'd get a better constant on the 50 ohms
I second that. Plus they're more water resistant and don't resonate as easily on UHF.
@@SkullfocherYeah, PL-259 & SO-239 are sometimes called UHF connectors, but what was considered UHF was a much lower frequency when these connectors were first designed.
@@rickgilbrt Yes I know that. Did you know though that at higher UHF frequencies the pin of the connector will become reactive and act as an antenna? Thus causing your swr to radiply increase. These are why most connectors designed for frequencies above 300 MHz typically use type N connectors or DIN.
@@rickgilbrt originally the UHF band was considered anything over 30 MHz until the reclassification of the frequency spectrum by the ITU between 1937 and 1942. But all that has nothing to do with my original statement. On "current" UHF frequencies, PL-259 and SO-239 (traditionally called UHF) connectors cause reactance and the higher in frequency you go, become more resonant, which is why they are not used for those frequencies. That was my point. It had nothing to do with nomenclature.
@@Skullfocher I understand that and wasn't criticizing your comment. I just think it's interesting that we sometimes still use outdated nomenclature - and accept that manufacturers sell outdated hardware. How many VHF/UHF mobile radios by "the majors" are sold with SO-239 connections? I don't know any that have anything else. As a new ham ten years ago, it was confusing to see "UHF" connectors on mobiles, and then read that the SO-239/PL-259 connector so are not actually good for UHF frequencies.
So a old school 10 to 12 meter operator operating 100' to antennas with rg8x 100' will mathematically be 100% loss !!!!!?? Contemplating 213 on these runs
I question the ocean jumps i get daily?? If 100% loss should be 0 at base of antenna
Heh, I thought that too, but think of it as walking half the distance to a wall, repeatedly. You never make it to the wall, but you get really close. Logarithmic approach to zero.
works the same for receive....
Apples and Oranges.
Ecoflex10 and ecoflex 15 with n connectors.
I tried for my ticket WAYNACK mid late 70s utilizing an ELMER who silent keyed as i hit 15 wds min onn keywork you know when code was REQUIRED
NOW ONLY TECHNICAL QUESTIONS NEEDED AND KEY MORE OR LESS HAS DROPPED BEHIND uses my practice unit was yaesu ft101e
Turning itt to 10 11 meter without am filter great radio but tight transmit recv locals had hard time understanding on am
👍🏽👍🏽👍🏽
Lmr 400 50 feet 😊
Next test, same but on 10, 20 and 40 meters. Lazy minds must be in the know!
BTW, the myth is the the length of coax in the mobile IS important... So they claim. First find out who "they" then see if they are correct.