What size coax for base station

[roadrage]

If it were me, I'd probably get some LMR 240 for the hundred foot run. Times Microwave also has a low loss RG-58 (LMR 200) that is a good, less expensive alternative. It can be purchased for $.49/foot, 1.7 db loss/100 feet @ 30 MHz, and about 1 KW power handling.

 

[Dutchman11]

I run across a deal on some LMR400 made by Times Microwave Systems for .80 a foot so I bought it. Hope it does the trick. Hope to be back home this week end. My honey and I are in northern Door County for our 37 anniversary. Looking forward to putting up my V58 and getting back on the air. Got my ol Stonewall out dusted her off and can't wait to get going, so please wish me luck. will show pics along the way if you see something I don':t please chime in It has been a long time since I put one up so all advice greatly appreciated.

 

[hammer0630]

I very recently put up a new antenna "Star Duster" and went with Times Microwave LMR-400 50 ft. and had to run coax differently than planned and had to get a 10 ft. jumper also T.M. LMR-400 and I use it for jumpers also, Before I got the 10 ft. jumper I was temporarily set up in the basement and had a 1.0 swr and after the extra 10 ft. jumper and barrel connector I now have a 1.3 swr and I don't know what to do about it but it doesn't seem to be noticeable. It is a little stiff for jumpers and I had to double stick tape some of my equipment down so it would stay where I wanted it to. It cost many times more than Chinese coax but I F'd up by not ordering 60 ft. and ordered 50 ft. I feel that the 10 ft. jumper raised my swr's and if it was 60 ft.solid it would maybe still be at 1.0. But in any case I am still way better than I used to be and the old antenna matcher went into storage.

 

[Marconi]

I very recently put up a new antenna "Star Duster" and went with Times Microwave LMR-400 50 ft. and had to run coax differently than planned and had to get a 10 ft. jumper also T.M. LMR-400 and I use it for jumpers also, Before I got the 10 ft. jumper I was temporarily set up in the basement and had a 1.0 swr and after the extra 10 ft. jumper and barrel connector I now have a 1.3 swr and I don't know what to do about it but it doesn't seem to be noticeable. It is a little stiff for jumpers and I had to double stick tape some of my equipment down so it would stay where I wanted it to. It cost many times more than Chinese coax but I F'd up by not ordering 60 ft. and ordered 50 ft. I feel that the 10 ft. jumper raised my swr's and if it was 60 ft.solid it would maybe still be at 1.0. But in any case I am still way better than I used to be and the old antenna matcher went into storage.

0630, I don't recall if I mentioned this or not about having some common mode currents on your new SD'r, but the change you see is likely just that...CMC's.

I'll ask again, what length dimensions and frequency did you attempt to set your M400 to at installation?

When we add a little feed line to our antenna system and we see a change in the apparent SWR at the radio...that suggests CMC. You then will see a little feed line transformation. Ordinarily I don't even worry about it with a SD'r because your match is pretty close if you didn't mess up badly in the construction, and get one radial for example set at a different length than the others, or leave something loose, all which can and will affect the symmetry and balance at the feed point.

Have you noticed any TVI responses at your location, or has a neighbor complained?

 

[W5LZ]

"...and had a 1.0 swr and after the extra 10 ft. jumper and barrel connector I now have a 1.3 swr and I don't know what to do about it but it doesn't seem to be noticeable."
Personally, I wouldn't do anything about that small a change in SWR. Your last 7 words in the quote pretty well give the answer to 'why'.
I think you have found out why most people use a smaller, more flexible cable for connecting to the radio(s). The amount of loss in a short length of cable isn't going to be discernible in most cases. If that 'jumper' isn't the right impedance, then sure, it can make a difference. So, just do like everyone else, make sure it's the same impedance as the rest of the system, or close.
SWR isn't a very good way of determining how 'well' an antenna system is working. It can only give an -indication- of how well impedances are being matched.
- 'Doc

(That 'nasty' RG-58 stuff works real well for jumpers, flexible, cheap, less aggravating. That certainly doesn't mean it's -the- answer to everything, but is is for somethings.)