What Coax do I use? 4 Tips to choosing the RIGHT coax for Ham Radio
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- Опубликовано: 11 июн 2024
- Here is 4 simple steps you can take to choosing the right coax FOR YOU. Don't go cheap. Pay as much as you can for the right stuff first time else you will be wasting your money. I explain. Callum.
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Don't forget What actually causes the loss..... It's more the reactance presented by the pF per meter. If you go down in frequency on 160m etc. A 100m run of 213 will deliver all the power. The OHMIC aka DC loss becomes more of your enemy. This is very true for AM broadcast. A 2kw service would use LDF450 for the run out to the tower ATU. For the DC loss and currents flowing. Not the pF per m losses that come into play higher up. 73s
You are a bright fella Peter!
@@DXCommanderHQ I deal mainly in the specialised area of MF NAS here in Australia. They are specialised licenses designed for special interest groups. Very much a "preach to their own flock" sort of thing....1611khz to 1701khz at 400 watts (AM). How to get decent results on the cheap, when everything is big and expensive requires some skilled guidance. That's me...
IIRC: f(t) = Ae^(-\alpha * j\phi) where \phi is complex. That attenuation term is always there.
I set my hair on fire and run across my neighbors lawn in my birthday suit trying to grasp all of this.
HAHA
Too funny!
Callum, after I collect what's left of my brain I'll watch this again. 😵💫 I come from the world of hobby rifle shooting where the scope will cost as much or more than the rifle. Very analogous to spending for cable and antenna for a quality result. You've opened up a rabbit hole for me now. Sigh,,,
Good analogy!
You picked feet? Bless your heart Callum, Sir.
Yeah, I have two of them!
@@DXCommanderHQ haha! ProudFEET! 👊🏻
Hello from the USA, Have watched many of your videos , and, have learned a lot about how to, and why. You mention the facts and go to the source to explian why you are mentioning the facts in a educational way. Enjoy your videos, Thanks for your work.
Thanks for saying!
Smiling!
Started like so many in CB 1972. Put up a used 3 element yagi, knowing nothing about it other then high SWR with my little Midland meter I ask for help on the air. Got a ton of do this or that comments, all were useless as I was soon to find out. The worst was trim the coax one inch at a time till you get a match. I about burned my fingers tips off putting that pl259 on and off more times than I remember. Been a ham now 48 years and realized how little most CB ops know.
We all started somewhere.
73
BRILLIANT story! Poor you, cutting that crappy coax! Funny now, I agree - I have similar memories!
M&P ultraflex 10 and their connectors is hard to beat for general hf
I love it when he whips out the drawings 👍
Brilliant videos as always , today's times are changing , there are more preppers & alike who are purchasing communication radios & there is a growing number of off grid communities , if the off grid communities become wider ,there may very well be a time when radio communication will become essential & even perhaps a part of daily life .
It's great that your ahead of the game , your the best in this field .
Excellent video. People mistakenly dump most of their money in their radio, then a little into their antenna, and then buy the cheapest coax they can. In reality you should spend the most of your money on coax then antenna then radio. People thought I was crazy for putting LMR-400 coax everywhere (it's actually DX Engineering 400MAX coax). It's expensive stuff, but the loss is very low and I can put any antenna anywhere (UHF/VHF or HF) and have a very reasonably low loss, even at 35 meters, at 50MHz, I still get 79% of my power to the antenna. At 40M, it's 92%. As the saying goes ... Buy once, cry once.
Very good point. And good on you for your effots!
Great videos, I just got back into 11 meters going to work on getting a technician's license but currently, I switched from some cheap RG8X coax 50ft in length to, what is labeled KMR400 coax. At first, my SWR reading on the RG8 was 1.4 to 2.0. Switched to the KRM400 which was advertised as identical to LMR400 and my SWR meter doesn't move on all 11-meter channels and I'm pleased with it. The next problem I ran into is some 3ft jumpers I got to add in a low pass filter to avoid my neighbors from saying to me I'm interfering with their electronics. Now that I look at the cable connectors you talked about and the soldering looks slightly off-colored from the jumpers I purchased. To me, they could have done a better job at soldering but from what I read about it makes a difference in craftsmanship. To end my comment by waving a hand to you here in the United States.
Dwayne, I hereby wave back at you! Have a GREAT day.
This is such great stuff, especially the explanation of velocity factor, it's a real help for a newbie like myself!
Great video to simplify the decision process.
Thanks! 👍
I am new to this hobby. This is great info. Thank you!!!!!!
You are so welcome! And talking of "Welcome".. I say "Welcome"!
Ok. That’s a LOT to unpack!!!!!
And that’s coming from a submarine Sonarman just entering the Ham world.
Just subscribed based on this video. Thank you
Woo-Hoo. Thank you!
I absolutely agree. All operators should take an antenna and coax led approach to their shack creation. The rig is largely irrelevant.
Great video ,thx for sharing bud 🎉🎉 🍻
No problem 👍
I’m mostly on 11 meter and 10 meter bands. RG 400 dual shield is the God of coax. 73👋🏻
i have M&P ultraflex 10 loss per 100m drum is 1.5 db @ 14 mhz cracking coax, now they brought out there new ultimate plugs thats next on the shopping list, a pal of mine just fitted the new plugs on some of the same coax, and he is getting nearly 10db extra on recieve on 17m ft8 compared to before he fitted them proof is in the pudding :), and the max power handling of the coax is 9kw key down on 80m cw
Quite right to mention the varying quality of cable, beware of some of the online vendors etc. Copper is expensive so cheap cable tends to not have much of it. Decent RG213 has a tightly woven shield, the off brands tend to be a bit "wispy", similar situation with RG58.
Yes, very good point..
When cal says just the tip he's not lying
Interesting topic, I hear somany opinions o what is the best coax.
It never stops!
The fact that the impedance repeats every half wavelength is one reason to have a certain length of coax. If done accurately (you could use a VNA or antenna analyzer) you would be able to measure the impedance of your antenna from the shack. I know of hams that do this, including an old bloke with a very reputable channel here on YT. I would expect more CBers to practice this as it's the one band.
I need 2 runs of 25ft for my proxicast mimo and after watching you I figured my budget and got kmr400 from a reputable brand. Seems to have the same specs as lmr BUT the sleeving is a bit cheap... But it's ok.
I use RG213 e.g. line length 50ft so frequency 14 mhz load SWR 1.5 total loss 0.399 @ 100 watts in 91.228 out 100 m roll £125.00 so im happy with that and i now use n-type as I love rubber seal inside the male plugs and the inner shield tube buts thats my choice !
I have ben into radios for almost 40 Years now +- a fuw But I Used to run a 3/4 Hard line for years with a 8 Element Beam on a 70ft tower an I could talk to the next state or two over from me very consistently after going to a good 3/4in Hard line the Rg213 just was not that impressive ! I also may or may not have ben using a Pride DX300 that had ben rebuilt & Beef d up from the ground up(Chris) It was bullet proof..Coax Really does make a Huge Difference ! Thanks for sharing
Yeah, that extreme hardline stuff is amazing..
Hey great video and lots of good advice.
Do you favor crimp or solder connectors?
Thanks for sharing
Erm.. I think if you have the know-how, crimp is probably very nice.
I'm using 70ft of the LMR-600UF with my DX-Commander Nebula antenna....Easy to install and low loss...Cried only once... For each purchase (antenna and coax)...:)
Very nice coax..
Being the cheapskate that I am, I use short rg58 for patching antennas, tuners, and radios together in the shack (using an old 10base-2 bulkhead panel), and then run 450 ohm window line to most of the antennas. I like twiddling muh knobs on the tuners though, lol. I'll have to finally buy some real coax when I get my DXC though. ;3
It's funny you should mention 10Base. 30 years ago I was installing a lot of Belden coax. I used it for hf radio as well. Compared to anything you could buy at the time it romped everything. The cool thing was in the quantity we bought it in it was dirt cheap. Dual foil, teflon, about 83VF. Made a big difference with low power.
Enjoy your videos, thank you. You continuously mentioned vaseline as a medium to fill your coax connectors and plugs.
It was 117° here the other day and I found that the Vaseline does not have a high temperature drip point. It ran out of my connectors. I did find some Automotive Dielectric grease which can be used on spark plugs and ignition parts which has a much higher degree drip point.
Perhaps this is something you should test or offer to your viewers.
Thank you
OK Mike, I don't "fill up" my connectors.. I only use them on the threads.
Ok, thank you for your answer. Well it also snows here and the snow will melt and find it's way into the connector, even from the bottom, for the snow above the connector.
This is why I fill them up with dielectric grease.
I found that Coax Length is less important, as long as your Antenna and Shack are both grounded properly, Then Ground/Earth has "0" Resistance
You mentioned you've done videos on how to fit modern pl-259 connectors. Do you have a link? I need to learn how to install them. Thanks!
Messi & Paoloni have videos on their site. Better than my pathetic attampt!
Will you also be talking about ladder line Callum?
We can do Ladder Line onthe live show in about 20 mins..?
Cool stuff…can’t go cheap on coax!!!
BTW…are you missing the D string on that white P bass??
Do, they're all there.. I'll check the footage. Maybe lighting was odd..
@@DXCommanderHQ Ya, I was thinking that when watching. You should do a small vid on the rundown of your musical equipment! 👍🏼
I did not know that cable length and half wavelength were important in a permanent installation. Now I'm curious to learn more.🤔
Most definitely. When I tune my shack antennas, I tune them at the end of the coax right before they go into my radio, but for field work, that would be an interesting thing to know.
I don't think it's CRITICAL if you are already aiming for approx a 50 ohm match - so DO NOT worry about this. I'm just using it as a tale because even on holiday, I am often developing and I just want an accurate measurement at the rig end. Most people shouldn't bother.
It's not that critical, if antenna system is matched there's little to be gained ,if not matched what's to gain ?
For a 50 ohm system, if you see different VSWR readings for various lengths of coax, it is your VSWR meter that is at fault.
No.. Impedance repeats every half-wavelength - and varies along it. So if you had 100 ohm antenna at one end, you would see 2:1 SWR every half-wavelength (less velocity factor) - and some weird curve between and other SWR readings depending on length.
Thanks for the VASELINE tip (You managed to get the vaseline in and didn't realise, lol), you could also use PTFE tape
Great tip!
I use LMR 400 , 75' and on 28MHZ I loose about 10 watts
Heh, heh...the BEST co-ax I've used, was Andrew's 3.5 in rigid line, filled with air from a dehydrator-equipped compressor. 3 in Heliax is damned good, too, especially if you don't want to mess with all those flanged connectors. That's what you need if you're running the "legal limit" (ie, 50 KW). Actually, I didn't own that transmitter, the University of Arizona did. I just repaired/maintained it.
And I was PAID to do that! How cool, to be paid for engaging in your hobby!
A thought...that xmttr's frequency was 1550 KHz. A little tweaking, and it could easily have operated on 1800 KHz. "CQ, CQ, CQ, 160, this is KUAT-AM...."
Paid to do that - wonderful!! :)
I've put my mates onto this calculator to convince them to even run Heliax with their beam antennas. This is because with gain, and high gain, (one runs a stacked pair of 6 elements) you will really miss out on the ERP with a lossy bit of coax, it's compounded.
Good point.
Good advice from you Callum.
I bought RG58 at a rally once. Next time I want to see what I'm buying because when I got it home I discovered the braid was very open weave and I wouldn't like to use it on 2m. I think I used it on my 60m inverted vee.
2m h/b 4 element collinear has about 20' RG58 and I can cut it down to about 8'.
I've watched a few videos lately by CB'ers about cutting coax or buying 18' of coax to get a good match at the aerial. Most comments were saying it's good advice.
I commented on one video why is it only CB'ers who have a problem with matching the aerial and not radio amateurs? I've never had any problems with my h/b aerials. They also said don't coil coax as it affects the SWR and can burn through the coax! How much power are they using? Again I said it doesn't matter if I run my coax straight or coiled, it makes no difference.
G4GHB
Hi Bill.. There is this myth that unfortunately CBers seem to have about very specific lengths of coax. Such a shame because it's genuine myth that "sounds" sort-of right - but as we both know, a total waste of time.
@@DXCommanderHQ Callum, Bill brings an old argument. I've had several barroom discussions that coiled coax produces an RF choke with dB loss. I don't believe it, and have never measured it. Do you have a comment on that?
Coiled coax IS an RF choke. And it will have loss because it's a longer length of coax only..
@@markw756 Well, yes, it is a choke, I always put one on my aerials and it certainly does block r.f. coming down but I can't imagine too much loss introduced. I made a 10m and 15m indoor dipole on one length of coax last week with a coax choke and used about 15 feet of coax with about 5 of that for the choke, even with RG58 I can't imagine much loss. SWR right down to 1.1:1.
Callum says below it's lossy because of it's length only.
With my one Watt yesterday on 10m c.w. I heard a guy calling CQ and we had a QSO. 1500 miles to Bulgaria.
A coax loss calculator shows a loss of 0.304 dB and 0.932 Watts out for my total coax length.
73, G4GHB
@@DXCommanderHQ Hi Callum.
Not a great loss though. For my r.f. coax choke which is about 5 feet, a coax loss calculator says: for an SWR of 1.1:1 which I have, gives a loss of just 0.101 dB, a loss of 2%.
Nothing to worry about.
73, G4GHB
Hi! I heard RG-213 is good. I reckon that RG 214 is also good. Is that correct? (it has 50ohm imp) I didn't find much info about the 214 cable used in radio, so i'm not sure if it's good. Many Thanks! :)
Yes, both fine. FInd some "coax loss charts" and plumb your frequency in and you can check.. Just remember that 3dB loss is half the power.
The TennTenna EFHW is designed to use 50' of coax according to it's designer.
Always dubious about specific lengths of coax.. Only because there was one antenna (I forget the name!) that when you worked it out, needed the coax as part of the radiating element.. Apparently it was lossy.. But what do I know..!
@@DXCommanderHQ Exactly, I guess I should have phrased it as a question! Why, when saying it doesn't need a counterpoise, recommend any length of coax? I'm not an engineer by any stretch and I don't understand the science of that design.
If I have to elevate a coax to cross a driveway, is there coax with a messenger cable or how long a span of coax will support itself?
Good question Raymond. I would use a thinner (less weight) coax, say Messi & Paoloni 7mm or SSB Electronics Aircell 7 for that stretch and just let it "droop" a bit. Actually SSB ELectronics do a super thin 5mm (under 1/4 inch) coax called Aircell 5 which is as good as RG213. You could use that for the lift. Messenger line good though. Any thin stainless wire and cable ties.
How long does coax last outdoors?? My Ham station has had the same coax since 1997!
Honestly, I don't know.. You can test it for loss....? I'll bet there will be some now.
I’ve been down a rabbit hole trying to find an FSJ4-50B (PL-259 Andrews) put on 1/2 inch super flex Heliax ,, can you help me ?
Hey.. Does this help? www.ebay.co.uk/itm/384721577421?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=IKJRDFI3Tnq&sssrc=2047675&ssuid=4aV5Q4xoQcG&widget_ver=artemis&media=COPY
RG-8x at a minimum from HRO.
Have we forgot about Coax is Unbalanced, and Ladder Line is Blanked, and i think all your references are for Balanced line which act different to coax
Wow! Any calculators for the variables with "mixed" cable? Say 100' of LMR 400 and 20' of RG8X for the "last mile"? LMR 400 is not very flexible for getting down walls and such. My layman's math at 145MHz says I lose 20w out of 100w in the first 20ft of RG8x and 30w on the 100ft of LMR? - KI5MEL
Mixed.. You can add dB losses together. So calculate say 100 feet of X and 50 feet of Y.
Any chance of a World Wide list of who makes what......? I constantly hear names I don't know......thanks in advance.... 73s
Oh heck, I don't know how I would keep that up to date..
Mainly what equals what? Not a "who stocks what" and where.... For example RG213 is a term used here like drinking water..... The "decent stuff" is made by RFI..... The next level up for less loss and a little stiffer (but the same size) is LMR400 from Times (I tink)..... From there it's the semi ridgid or corragated stuff (alot more stiff) commonly spoken of as LDF450 (here) which is Andrews........ All of these are American names..... Step off these NAMES i'm stuffed..... Watch American videos and they don't even use LDF 450 to speak about Andrews cable.... its got a different name (insert pic of me with a blank look).....
I'm sure the laws of physics don't change - but the names do! Further example is -- Here we say Gyprock (it's a brand name i think) - the yanks call it Drywall (not sure if thats a brand) --- its all plaster board used in houses for walls.
Can you join the dots? Maybe a topic for a future video? The Many Different Names For The Same Coax.
cheers
@@petertate3436 I get very confused with the brand names and prefixes too. I like the Time Microwave calculator and it has a few synonyms. I cannot afford anything LMR so that helps ! I stick to window line and RGXX.
BTW we also call drywall, "sheet rock" and "gympson board".
I've been looking at this recently and on paper, F-Zero coax seems to hit the spot in terms of price:performance (about £150 for 100m, with a loss of 2.35 dBd over 100 m at 30 MHz). Does anyone have any experience of it?
Couple of my club members use it for HF and say it's pretty decent.
Only downside is being solid core it's not the easiest to fit from a purely mechanical perspective.
Westflex103 is comparable in price and quality and is much more flexible
Stuart, check Dan's reply :)
@@dasy2k1 @DXCommander - Brilliant, thank you both. Made some enquiries about WF103 recently and it's OOS with Westlake. Think I'll give the F-Zero a go and see how it goes. Thank you!
What about multiband antennas? Which length?
Any.. Lengths of coax have no bearing AT ALL on what 50 ohm antenna you are using.
@@DXCommanderHQ A, okay. I thought that I need exactly multiplication of half waves for each band. So, if antenna is tuned properly, it will work with any coax length?
What about RG Mini 8 coax this is what I use on my CB set up about 30 foot
30 feet isn't THAT much. Run it through the calculator..?
@@DXCommanderHQ It came back very good Callum lost about a 1/4 of a watt on 4 watts , My SWR is 1.1 / 1.2 dependant on weather
@@quotagious 13% lost isn't the end of the world. I'm more surprised you're talking to anybody on the chicken band with 4w. I'd think the guys on CH6 from yesterday would still be stepping on ya halfway up the dial.
@@chublez They are mainly mobiles I speak to when they are on on the A1 there is nobody on in the local towns anymore I'm on a bit of a compass for 5 towns within 15 miles as the crow flies and there is nobody on in any of the 5 towns if there is they are very quiet , I here station from nottingham but don't expect to get to them when they are running if they didn't run I wouldn't hear them ,
Shame it's gone like it has :(
Im interested to know your reason for not liking to use 213?
Most RG213 is copied and has become an over-used term for anything at around 10mm diameter.. You never quite know what you're getting for your money..
@@DXCommanderHQ yes, I totally understand. Can you suggest a reputable manufacture of 213.
Sounds like photography ... it's the lens that you depend the money on ... and then you have to buy different ones for different distances. You end up spending way more than on the camera itself
Ugh!
Feedlines become impedance transformers with standing waves on the line
Huge topic.. Can depend on where you measure it :)
@@DXCommanderHQ is certainly a huge topic, the impedance on the line at the radio will differ with line length when there is a mismatch at the antenna probably where the certain length myth began ,that would depend on frequency also
Even on a mobile installation, mag mount or a fix mount usually comes with rg58 and on 70cm only 5m of rg58 is near 2db lost, and the pirate shit is even worse. Lost from a couple off connections and you find out the handhelds stock antenna works better in side the car then the short antenna you have on the roof
It's actually quite easy to test with dmr the repeater will report your singnaali strength in db to brandmaster and you can check the last heard station, don't know how accurate it is, but better than any off my radio s meters
LMR-400
That's it!
I find it bizarre that we still use thick coax, or any coax for that matter, for long runs on HF when ladder line is cheaper and has virtually no loss. Sure it needs a balun before entering the radio, but that's not a bad thing to have and if anything it makes things simpler. Here is the thing, you don't even need to drill a hole in your wall if you fancy trapping it through the window opening ( not the best advice but it is still possible. ) The side effect of using ladder line, well apart from virtually no losses, it makes wire antennas usable on more bands. So can someone tell me... why on earth are we still buying coax? ( I suppose a meter or two to get from the balun to the radio is excusable )
Because you can't drive a multiband resonant antenna with ladder line. Well you COULD .. but I'd love to be a fly on the wall when you do a band change. And also try burying that stuff...
@@DXCommanderHQ Very good point. Power as well, because I wouldn't want to shove too much through a feedline, 100w of course I would. I wonder why you would want to bury a feedline?
M P coax cables does not have the cheep tinfoil that the LMR cables and there knock offs have.
I'm a QRP operator and even a 1 dB loss is significant at 5 W. Here's a few things I've learned for low power ops but are not necessarily important with QRO.
1) PL-259 are not 50 Ohms and have insertion loss. Use BNC, sma, or N connectors.
2) Avoid coax whenever possible, use ladder or window line.
3) Avoid RG58 and stick to RG8X even for jumpers if you can.
4) Only buy good brands like Times Microwave whenever possible.
5) Don't forget that your antenna design will get you back some gain from the radiation pattern assuming you have a specific take off angle in mind.
6) Avoid cable adapters. Make the jumpers you need with the exact connectors required.
7) FT43-50 toroids fit nicely on RG8X cable and 20 are affordable. Less loss than 1:1 choke if you don't expect a lot of common mode currents.
8) Z matches have less loss than PI and T networks paid for with less bandwidth.
9) Anything end fed should have an RF ground of some kind.
PL-259 & SO-239 acts as a attenuator over 300mhz, so N-Type or BNC is Required, So Agreed
Ladder Line is Balanced
Coax is Not
What you say is 100% correct
@Nonoko Dog Excellent advice. Weirldy, I believe QRP ops and QRO ops are both after as less loss as thay can cope with. Both are extremes. It's the regular 100W station folks that forget all this good advice.
@@DXCommanderHQ Good point boss. I was just reading some good articles on TOA and think I'm wrong to worry about it so much. Could you do a presentation on that topic ? Sounds like a good uniform rad pattern is more important that high gain at specific angles.
My end fed has no ground. Ive talked around the world with it. So no, an End Fed doesnt NEED a ground. Why say that?
@@paulkazjack You're right...I should have written, "have a choke of some kind".
Not Vasoline, use Electrical Contact Grease
DIfficult to buy at the Pharmacist :)
If you're refering to dielectric grease you're incorrect.
Dielectric grease stops electrical conductivity.
i dont in radials, and also not in coaxx rg 58 basta
73
"The specialists" tuning and tuning..... and tuning.... like crazy... until they get the last 100th of a db out of the amp or for 1:1 point 0 0 0 0 0 0 0 swr of an "antenna (coax) tuner" (muuuuhhahhhahhhaaaa) ..... of course, in the band pass and not at zero beat. Bet a million, these are the same specialists, never understood how to solder a GOOD quality pl259 without rapping a soft coax. For them, the industry offering today this overpriced but unnecessary deluxe plugs. An experienced Ham always using soft coax ONLY, if no other alternative is possible. Besides this, there is NO alternative. Hardline is the choice for longer run's. it will last a lifetime and is the Only real rugged cable. If the cover is injured, and it will be one day, nothing happen. In that case, softcoax is killed and dying slowly.... 1/2" hardline is not much more expensive than GOOD Q RG213. Ecoflex15?? Things, the world don't need until hardline in all dimensions is available (for lower price!). 2m/70 guys need the right coax, not an RX preamp. Buying coax 2nd hand? Never soft coax, hardline allways. Cheaper than new HI Q RG213....... we're always fighting for the last half db. A pro for both ways.
Most of this series has been focussing on the newcomers, therefore some of the easy / economy coax was featured and a way of understanding the losses. But thanks for the comment!
Thank you. Good advice. N0QFT
Any time!