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Posted: 9/8/2020 1:03:17 PM EDT
[#1]
Open feeder an option?
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Posted: 9/8/2020 1:05:47 PM EDT
[#2]
Quote HistoryQuoted: Open feeder an option? Nope. Everything needs to be underground until it gets to the antenna. On the bright side, I have tall trees now, so I think I may be able to do an elevated wire vertical which will cut down on a lot of the hardware I needed to have at the old place. |
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Posted: 9/8/2020 3:19:14 PM EDT
[#3]
LMR400 ultraflex? Its a bit more malleable.
For HF you can use 213, for UHF/VHF I would use something like LMR400 or DXE-400MAX I have a run of 400MAX direct buried for 250' with no issues, its flexible, but also a PE jacket that is a bit tougher for bury. |
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Posted: 9/8/2020 4:58:22 PM EDT
[#4]
I'm a LMR fan. But bigger is always better.
As ultraflex was suggested above at 30MHz at 100 meters the ultraflex has 2.7db loss where standard 400 has 2.2. |
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Posted: 9/8/2020 6:05:09 PM EDT
[#5]
Use th coax loss calculator to simlulate what works best:
https://www.qsl.net/co8tw/Coax_Calculator.htm it all depends on frequency and distance. I use LMR400 for my HF, but for VHF/UHF due to loss in the cable, I used 3/4" Heliax - If I'm paying for watts out at the antenna, it's worth it to me. I also recommend using the antenna farm: https://www.theantennafarm.com/catalog/ They will sell it to you by the foot, or will custom make it for you. I custom made the Heliax because the crimpers and dies were too cost prohibitive for how many times I'd use them. However I did buy an LRM400 crimper and dies because they are cheaper and I use the hell out of them. |
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Posted: 9/8/2020 6:49:02 PM EDT
[#6]
Just to add info it's the HF run that will be 200+ feet. And that's almost always 40/20M for me so loss isn't a real big issue.
The V/UHF run will be under 100 feet. I sit in a valley now and can only hit a couple repeaters so it's not super critical either. |
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Posted: 9/8/2020 7:19:07 PM EDT
[#7]
spec'd and installed miles of LDF4-50 and LMR-400 for many .gov projects over the years, mostly < 140' (~).
Go to a 7/8" for longer runs. Customers have wanted LMR-600, and had the success they wanted... I'd check performance for the freq/length you want and crunch the numbers. For every dollar you spend on radio, spend 99 cents on the antenna/feedline. remember line losses work both ways (tx & rx) don't forget SPD's |
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Posted: 9/8/2020 10:19:58 PM EDT
[#8]
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Posted: 9/8/2020 10:23:58 PM EDT
[#9]
I kinda like the idea of trenching in sprinkler line and running one end all the way inside then terminating the other end in a weather proof box at the antenna base, run cable inside it.
I run LMR for everything but mostly because I buy surplus chunks of various lengths. |
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Posted: 9/8/2020 10:29:12 PM EDT
[#10]
I would get the Bury-flex. Keep in mind it's not flooded, but considering your environment I doubt that's really an issue. I'm not a fan of the aluminum center conductors (actual LMR400) for a lot of installations.
If you're running full legal power-ish, you might be pushing the thermal limits of standard 400 size cables considering your environment... I don't know how deep you'll be burying them or what the ground temp and dissipation is like. You could use Times "high power" 400, or a plenum type cable with FEP center insulator, or go up to 1/2 heliax, but all those would be a big jump in cost. |
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Posted: 9/8/2020 10:47:16 PM EDT
[#11]
For HF it's 500W max, and realistically it's more like 125W. I'm hoping I can do 250W with the antenna farther away.
I'm leaning strongly to the bury-flex, it's a known entity, its got the features I want, and it's something that HRO stocks, which is a plus. I'm not looking forward to trenching 200+ feet. I'm not planning on going very deep (maybe 6 inches or so). It's very rocky soil especially at the antenna site which is pretty much solid basalt chunks with pine needs spread on top. My plan is to run it to the site, terminate in a box with a ground and a polyphaser protector, and then run a shorter run about 10' up a ponderosa tree, to terminate at a tuner. The antenna plan is a 40M 33' 1/4 wire vertical with two resonant radials 10' off the ground, and then see what the tuner can do for other bands. If it can't do at least 20M I'll probably go back to ground mounded radials and figure out some way to support my old 43', maybe a ballasted pipe mount or somehting that doesn't require a hole in the ground. |
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Posted: 9/9/2020 6:40:33 PM EDT
[#12]
I use RG-213 for HF and RG-8X for VHF. I don't care about the loss on VHF because I can hit the furthest repeater 33 miles away with an HT in my back yard so losing 1/2 the power of 50 watts on VHF with a 7dbi gain antenna 30 feet up is already overkill.
I guess RG-213 is stiff but it is rated for burial, I think. |
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Posted: 9/9/2020 7:27:50 PM EDT
[#13]
A cable I like a lot is the relatively uncommon LMR300 and similar types (CNT300, RF300). For the run you mention (250 feet) it's on the fringe of being detectable amounts of loss on HF... Times calculator says 0.7dB difference for 250 feet on 20 meters. For 500 watts or less the power handling should be fine. Cost wise it'd probably be close to Bury Flex though, so I'd probably just stick with the 400 size cables.
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Posted: 9/9/2020 8:08:00 PM EDT
[#14]
Where is the best place to buy cable? I tried looking at HRO but their site doesn't make it easy to find what you need.
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Posted: 9/9/2020 8:18:15 PM EDT
[#15]
Quote HistoryQuoted: Where is the best place to buy cable? I tried looking at HRO but their site doesn't make it easy to find what you need. Iv'e always had good luck with https://thewireman.com/ |
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Posted: 9/9/2020 8:52:57 PM EDT
[#16]
Quote HistoryQuoted: Where is the best place to buy cable? I tried looking at HRO but their site doesn't make it easy to find what you need. we got our stuff (commercial) from these places, in this order... shopped elsewhere if they didn't have it by some chance. https://www.talleycom.com/ https://www.tessco.com/ https://www.pasternack.com/ |
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Posted: 9/9/2020 9:28:24 PM EDT
[#17]
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Posted: 9/9/2020 11:40:34 PM EDT
[#18]
Quote HistoryQuote HistoryQuoted: Quoted: Where is the best place to buy cable? I tried looking at HRO but their site doesn't make it easy to find what you need. Iv'e always had good luck with https://thewireman.com/ Thank you very much sir! Oh just reloaded the thread, thanks to everyone else as well. Will check them out. |
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Posted: 9/9/2020 11:58:19 PM EDT
[#19]
Just as a FYI to others, like many things, there appears to be an unusual number of suppliers that are out of stock on coax and other antenna-related things like specialty wire.
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Posted: 9/21/2020 12:57:47 AM EDT
[#20]
Quote HistoryQuoted: Iv'e always had good luck with https://thewireman.com/ I went there looking for some stuff over the summer and with the reductions in items available and several things out of stock, kinda wondered if he was going out of business. Would have thought this year might have been good in the mail-order amateur radio stuff business, but could be wrong. |
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Posted: 9/21/2020 1:22:46 PM EDT
[#21]
Quote Historyyou need a drip loop on the far right cable |
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Posted: 9/21/2020 6:00:05 PM EDT
[#22]
I get my cable from Joel:
https://rfconnection.com/ LMR-400 for UHF/VHF, RG-8X for HF, nothing buried. |
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Posted: 9/21/2020 6:41:39 PM EDT
[#23]
My spool of bury-flex showed. I think they should drop the "flex" from the name, that stuff is pretty stiff.
It'll be fine for the main run but I'm going to have to use RG-8X or 1381FX or some other flexible stuff for the interior-to-grounding-box run. On the positive side, it's stiff enough I won't be running it through conduit, so it really will be direct bury, which should save me some time and money. |
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Posted: 9/21/2020 8:04:29 PM EDT
[#24]
Quote HistoryQuoted: My spool of bury-flex showed. I think they should drop the "flex" from the name, that stuff is pretty stiff. Quote HistoryQuoted: My spool of bury-flex showed. I think they should drop the "flex" from the name, that stuff is pretty stiff. It's only flexible by comparison to LMR400. Anything with a polyethelene jacket is going to be stiff. It'll be fine for the main run but I'm going to have to use RG-8X or 1381FX or some other flexible stuff for the interior-to-grounding-box run. http://www.davisrf.com/rgcoax.php I'm not sure if it's the WM102 or WM106 that I've used before, I'll see if I can find a piece later. Wireman no longer has it on their site. I think it's the RG8X-LL that I've also used that I really like for jumpers and such, if an RG-8X size cable will work for you. Sure a lot easier to route that around that a 400 size cable. On the positive side, it's stiff enough I won't be running it through conduit, so it really will be direct bury, which should save me some time and money. |
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Posted: 9/21/2020 9:52:17 PM EDT
[#25]
It's under 20 feet to what will be my demarc box for the outside coax, so I think I can suffer some RG-8X. I'm putting in 1/2" ID ENT smurf conduit between the antenna outlet box and the crawlspace, so I should be able to swap out flexible cables pretty easily if it's an issue.
Fortunately I ordered 50 feet of it when I got the spool, thinking I might need to make some jumpers. I also have some premade RG8X 25' and 50' cables I can cut in half and solder on new connectors that should work as well. Having a crawl space rather than an attic makes antennas a hell of a lot easier. I don't like how noisy footsteps are v. a concrete pad, but for ham stuff it's a big win. |
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