With that kind of coax run, you'll definitely want the lowest loss feedline you can afford, and you'll probably want the pre-amps sooner than later. If hard line is out of the picture, LMR 600 is a good alternative. Several outlets will sell custom lengths with connectors attached. You can get by with LMR 400 or Belden 9913 on the 2 meter side, but loss at 435 MHz will be greater. I would avoid the diplexer like the plague.
As GEO mentioned, you really only need the flexy stuff at the point where things are rotating. I run LMR 600 to the pre-amp, just below the rotor, and ultra-flex from the pre-amp to the antenna. A good, moderate-cost alternative for pre-amps are the "Mini" pre-amps from SHF Elektronik in Germany http://www.shf-elektronik.de/en/ -- Mark D. Johns KØJM / MØGZO / ex-9H3DJ / ex-KØMDJ Brooklyn Park, MN USA EN35hd ----------------------------------------------- "Heaven goes by favor; if it went by merit, you would stay out and your dog would go in." ---Mark Twain
On Sat, Nov 17, 2018 at 1:12 PM GEO Badger via AMSAT-BB amsat-bb@amsat.org wrote:
Keith, You want the lowest loss coax you can afford for your run. ½" hard line would be a good choice, though not inexpensive and neither are the connectors. Plus it is rather rigid and can be difficult to handle. Terminate it at the rotator and use a flexible jumper from there to the antennas. To use a diplexer you'll need one at both ends, assuming 2 antennas. Recall that a diplexer will have insertion loss of >3 dB. And that I don't believe they will pass DC. Though I haven't ever checked that. --- Ciao baby, catch you on the flip side. GEO
Time flies like an arrow, fruit flies like a banana.
From: "Keith E. Brandt, WD9GET" <wd9get@amsat.org>To: amsat-bb@amsat.org Sent: Saturday, November 17, 2018 10:11 AM Subject: [amsat-bb] Station advice: coax
There's been a lot of good station advice on the reflector recently that I've really appreciated. I'm slowly but surely building up my sat ground station. I've got my Yaesu G5400B connected and running and I've got an antenna plan. The next issue is running coax.
What's the recommendation on coax runs? It looks like I'll have between 75 and 100 ft from the shack to the mount. I can envision running a separate line for 2m and 440, but is it also effective to use a diplexer at the antenna? Does that limit my ability to later add a mast-mounted preamp with power-over-coax? (I'll probably add preamp(s) at a later date)
Is the ultraflex coax really necessary for hooking up around the rotator? I'm sure it's better, but is it really worth the extra cost? I certainly don't want to pay the high price for ultraflex for the full run, especially if I'm using two lines.
Thoughts appreciated.
73, Keith --
Keith E. Brandt, MD, MPH /wd9get@amsat.org/ /Christianity and science are opposed… but only in the same sense as my thumb and forefinger are opposed- and between them I can grasp everything. /—Sir William Bragg (Nobel Prize for Physics- 1915) *This message transmitted with 100% recycled electrons _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb