InterceptRadio.com Forums

What are you guys/gals running for your antenna/Coax combo's on VHF/UHF base radio?...

Im thinking of picking up a Comet GP-6 ( Or GP-3 as a second choice), and running 50' of 9913 for the coax. I ask this question on the ham boards, and get the standard " I dont run anything but LMR400" and the whole line of different antennas. I live out in East Sno county between Monroe & Sultan on the North side of SR 2, so my elevation is pretty good except for the huge hill across the valley from me, and to the east of me, and well... yup Im pretty much socked in.. :roll: I seem to be able to hit the major repeaters with just my home made Rollup J-pole in a PVC pipe hanging off my back deck about 12' in the air, and 40' run of Ratshack RG58 to a Yaesu 8800 (I have a new 857D still in the box for when I get the new "man room built". What Im trying to do is get my simplex range up to something better than "Across the valley". Im getting tired of being able to hear a guy I know in Darington talk simplex to a guy in Lynnwood, but I can't seem to get much past the Tualco valley, or the town of snohomish. Im getting ready to build a new house ( with a second story on my shop for my "man room") so when that is all done I will be able to get my antenna's up at about 40'. For now I have a 25' TV mast that I can mount the GP6 on, and that should bet my tip at about 35'. I cant help to think It will be better than what I have. :shock:


Im loving messing around with this new hobby, but life was a lot easier when I was just running a scanner. Maybe Im just doomed to NVIS with my HF rig. :mrgreen:

_________________
Respond on Tac 3

I have owned a couple of Comet antennas, first was the GP3 and now the GP9. I have a 60' run of LMR 400 going to a Kenwood V-7A.
I live in Federal Way about 300' between a couple of small hills.
Having used RG 213, 9913, and LMR 400 I have to agree that for the money LMR 400 can't be beat. You didn't want to hear that but it works best in my situation.
I can reach Canadian repeaters at times, and get as far south as Vancouver WA. A few years back I talked simplex on 2 meters to Astoria OR. Overall the setup works well.

Vince.
KD7OLP

If you're REALLY worried about the loss figures and want to compare, try this calculator:

http://www.ocarc.ca/coax.htm

Running some generic figures at 446.000 mhz, 100 feet of coax, and considering a decent match, there seemed to be less than a db difference between 9913 and LMR-400. Not real appreciable loss between the two. And, if you have a real efficient, high gain antenna, then perhaps you can afford some loss in the coax. However - maximizing the coax with a good antenna is optimum.

In general - If you stay away from the RG-58 and 8X type of coax for long coax runs on VHF/UHF, then you're off to a good start. Long Coax Run = more loss = worse performance.

For myself - I'm running some 9913, RG-8 flexi, and I think there's some RG-213 up there. But, I do have some elevation - so that helps, too.

Brad/N7JGX
Whidbey Island, WA

_________________
Whatever.....

http://www.ocarc.ca/coax.htm

OK that is just too cool!...


A guy at work was talking about a GP-9, I will have to look into that one. I hope to make that call to HRO later on today.

_________________
Respond on Tac 3

T68,

Do you have any problems weather sealing it?...

I have one guy telling me how he has "never seen a piece of 9913 that was not corroded down the length of the center conductor, and no matter how well you think you waterproof it, you still have condensation in all but the desert"...

I guess I should quite trying to be such a tightwad, and spend the extra cash. It would be easier. :mrgreen:

_________________
Respond on Tac 3

On the stuff that have exposed connectors, I've bee using a silicone self-sealing tape. That seems to work well.

Most of my stuff (Comet/Diamond type antennas) have the connectors shielded from the weather.

So far, I haven't noticed any problems with my coax - however, most of it is newer runs (less than 5 years), so perhaps this stuff hasn't been exposed long enough yet. Or, I'm just lucky...

Go with the better coax, if you can afford it. It may give you a slight performance edge and save you the time/hassle/expense of replacing it pre-maturely.

Brad/N7JGX
Whidbey Island, WA.

_________________
Whatever.....

Ken,
Can you bring up Pilchuck 2m from where you're at?
When I lived in Monroe, I remember that area is kind of a 'black hole' for radio signals.
That Woods Rd hill blocks a lot.
There used to be a 440 machine on Haystack.

Im up in the hill between Monroe, and Sultan. Pilchuck is fin from where Im at, but I can lose it just by going down the road. Monroe seems to be in the shadow in a lot of places for it. Im usually on Pilchuck, W2ZT/220 ( I love this one), I also like to try and work the W7SKY (440 machine) when it works, which is almost never.

_________________
Respond on Tac 3

I used 9913, then went to LMR400, and now use LMR240. You will notice there isn't a significant difference in loss between LMR240 and LMR400 for shorter runs (<50 ft), not to mention you can use RG59-sized reducers on PL259 and N connectors.

LDF5-50 on the isopole :mrgreen:

9913? :puke:

LDF4-50 on the "too low to the ground" 6dB gain Sinclair Radio Labs 222
stationmaster!!!

Everything else is some flavor of RG 8, 213,214,9, etc... as runs are under 40 feet. Except on the Bus... Most of that is LMR 400, except as much of the interior interconnects as possible are done with some flavor of "superflex" either Andrew FSJ4-50 or equivalent by other manufacturers.
All 9913, :puke: or worse, 9096 flexible, :puke: has been turned into scrap after removing the connectors :!:

Brad, I would say you are LUCKY that 9913 :puke: has lasted as long as it has. The REAL issue with it is that it seldom remains 50 ohms after installation. :puke: That spiral plastic that is SUPPOSED to keep the center conductor centered, seldom does, and what you end up with is a spiral-wound center conductor rolling around where it is supposed to be evenly spaced from the shield conductor. And that is when the loss at VHF and above becomes :puke: worse than RG 58!

I suppose it would keep ignition noise off the DC to the radios though :lol:

Eric
KB7DQH

_________________
That is how the people at DARPA think. they take things and use them in unconventional ways, to see what happens.

I run now LMR400 at the base.

For about 2 years I used RG-6 coax I got for free from a friend. Even with the 50/75 ohm mismatch which made the SWR at around 1.2:1, I got by just fine and my equipment didn't fuss. I replaced the RG-6 coax later on only because I wanted to move my antenna back a bit more and well, it was easier to run a new line than trying to reuse it.

_________________
Mt Wave SAR member
Support Search & Rescue: Get Lost!
http://www.mwave.org

LMR400 on the VHF
and just this weekend replaced the LMR on the HF for 450ohm! wahoo

_________________
If I had an antenna, I would; but I can only transmit on 160 meters.
_____
DE K7MHI

I've been using RG-213 for most of my radio applications. I recently put my scanner antennas on LMR600 with N connectors. It's a bit overkill, but I said what they heck...

In terms of "hearing", I was pleasantly surprised. I really didn't expect a huge signal improvement but the drop of the noise floor was pretty dramatic.

I haven't decided if I'll do this for my HF antennas as I'd probably have to bury the coax to keep it out of the elements. And for HF, the signal loss is almost the same.