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1/22/2020 12:12:56 PM
Posted: 4/21/2016 1:49:47 PM EST
Was looking at replacing my feed line with something much shorter. Currently running 100' of 240 but probably only need 50' or so since I've moved my setup around in the house.

Looking at what it costs for 213, 8U, and 400UF assembled cables, the costs are all about the same. Assuming environmental performance characteristics of the three are acceptable (UV exposure, bend radius, etc) why not go with the 400UF for HF work?


Link Posted: 4/21/2016 1:57:07 PM EST
Yes it would work, but I would save the money and use RG-213 for only a 50' run on HF.

Link Posted: 4/21/2016 3:14:23 PM EST
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Originally Posted By K9-Bob:
Yes it would work, but I would save the money and use RG-213 for only a 50' run on HF.

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Cost from what I'm looking at is pretty much the same. I've heard good things about the 400Max that DX Engineering sells, particularly UV resistance, which is important here in the Mojave.
Link Posted: 4/21/2016 3:31:47 PM EST
I've been using DXE-400MAX for 4 years, and so far, so good.


Of course, it only runs from the spare bedroom shack, to the attic.
Link Posted: 4/21/2016 3:50:26 PM EST
[Last Edit: 4/21/2016 3:58:01 PM EST by Gamma762]
The knock I have on the UF cables is that the jacket is so rubbery that it doesn't support the braid at all, and if the cable gets flexed around a lot at the connector the braid wires start failing. I have seen that with both 400UF and 240UF. Solution is good stress relief at connectors. Otherwise no reason not to use it if the cost is the same, but frankly for a 50 foot run for HF I'd be using an RG-8X/LMR240 size cable instead unless you're running QRO. And maybe look for a lower cost RG-8/RG-213. (ETA: except for the issue below)

Originally Posted By BroncoGlenn:
I've heard good things about the 400Max that DX Engineering sells, particularly UV resistance, which is important here in the Mojave.
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It's just polyethylene jacketed, which all the standard LMR and most of the clones all have.

An issue that escapes notice in a desert environment is heat build up in the cables. A black jacketed cable out in the desert sun can reach a very high internal temperature. such that the power handling of the cable decreases dramatically and can lead to center conductor migration problems. You can get white polyethylene jacketed cables which helps the heat buildup, but they're much harder to find. Solid dielectric instead of the foam types helps cable integrity and avoiding center conductor migration at high temps.
Link Posted: 4/21/2016 3:51:08 PM EST
DXE-400MAX is all I've been buying lately. Use it for 160 meters to 70 cm.
Link Posted: 4/21/2016 4:15:32 PM EST
I have a 175' run of the DXE stuff.

Not my first choice to do so, but I actually direct buried it and it has been holding up for the last couple years. If it's the same price I wouldn't mind using it at all.
Link Posted: 4/21/2016 6:34:59 PM EST
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Originally Posted By Gamma762:

An issue that escapes notice in a desert environment is heat build up in the cables. A black jacketed cable out in the desert sun can reach a very high internal temperature. such that the power handling of the cable decreases dramatically and can lead to center conductor migration problems. You can get white polyethylene jacketed cables which helps the heat buildup, but they're much harder to find. Solid dielectric instead of the foam types helps cable integrity and avoiding center conductor migration at high temps.
View Quote


Ya know I just remembered when I first put up my antenna I thought about painting the coax white to help keep the heat out of it. I was thinking the prolonged expose of solar radiation and high air temperature would screw up the dielectric over time.

Yesterday when I was tuning up for the net I was getting infinite SWRs on everything. Ended up disconnecting the feed line from the antenna reconnecting everything and bingo-bango it was fine again. So I don't know if I've got som jacked up feed line, balun, or whatnot going on, but something I'll need to keep an eye on.
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