Running a President McKinney mobile, Midland HF747 amp, which is putting out between 90 and 110 Watts, 9' whip dead center the roof, 9' RG8X coax radio- to-amp, and 18' RG8X amp-to-antenna. Cheers!
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Pringles Can CMC Choke
- Thread starter Chicago Savage
- Start date
I spent a long time experimenting with different lengths, shorter and longer, tried 3 different coax types, including LMR240, for both the amp jumper and the antenna feedline, all with varying SWR's, and my 9' whip loves a 9' jumper, and 18' run to the antenna of the cheap clear-jacketed RGX coax found at most truck stops. My SWR is 1.0 to 1.1 across the 11m band, and that is difficult to achieve on a mobile setup. Especially since my car is so tiny. Wow! That was long-winded! Lol
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did you sandpaper the paint on the grounding side of the mount?
IMO it seems to be a ground issue as i never had problems till grounds needed polishing up and a kw on the key
IMO it seems to be a ground issue as i never had problems till grounds needed polishing up and a kw on the key
You created a nice tuned inefficient setup. SWR isn't everything. I normally run with an SWR of 2. I think you need to reexamine your setup.
wondering about the mount. what kind is that? the hole in the headliner looks small. just wondering
From you, w9cll, I knew that was coming. It's alright. It's all part of the game, and I'm always willing to listen.
It's a mirror mount with a heavier-duty stud. Goes through the roof panel, and support bar. Meter says ground is good. Yes, I have to clean up the hole. Haven't found the right grommet.
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Just stating the obvious, you have over 20' of cable in your car. Sorry this is hilarious. You seem to be using an amp to over come a fairly poor install with high loses. While the choke is a good idea how it is mounted is not the best. I will back out of this you obviously seem to know more.
Come on W9cII, don't back out with your idea just left hanging out there. Give us some real details on what your SWR of 2 setup is all about, why and how such an obvious mismatch is more better than his inefficient setup (your words).
I don't think CS was trying to come across as being smarter than everybody else...explaining to us his setup. Right or wrong, he told us what he was doing with his mobile.
We all want to be 10-8 and great.
I don't think CS was trying to come across as being smarter than everybody else...explaining to us his setup. Right or wrong, he told us what he was doing with his mobile.
We all want to be 10-8 and great.
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I don't claim to to be an antenna guru at all but I also am not a slave to the SWR meter either. I do know that I have found that most antenna seem to work better with a slightly higher mismatch. Case in point, in the car I use a screwdriver and I tune for maxium signal strength, once I get that setting I will then check the SWR, 9 times out of ten the SWR will be over 1.5. If I tune to the SWR meter I have less signals.
A lot of people are slaves to the SWR meter and I was mealy pointing out that will all that coax in his car he created a good match for his radio but not an efficient antenna and that he probably has something else going on in that setup that is causing the mismatch. While you and I both know that on 27mhz 20' feet of cable is not going to produce a huge loss but I can only assume that the cable is being coiled up in the car to save space and this is not the best option.
I bow to your knowledge of antennas but I am not a novice to this either, in my previously mentioned car I have 4 1/2 feet of cable going to the antenna. This is accomplised by having the tranciever mounted in the truck and the use of a remote head (ICOM 706MKIIG).
Maybe I am all wet here but I feel I know what I know...
I always ran just enough to get from radio to amp and then just enough coax to get from amp to antenna. If I had a mismatch I would begin looking elsewhere for issues. As long as I knew my connections where good (good coax, good soldering on connectors) and my mount was properly installed I normally never had any issues on the analyzer. I would rather have a 1.5 with direct (no coax coils) connections than 1.0 with coax run all over the place...
I'll concur to that.
I used to think the same until I learned over the years that low SWR is fine but it depends what it takes to get that. More often it's because high loss matching making a SWR meter look good and making one think an antenna has extreme bandwidth.
Even a 102 whip doesn't have a bandwidth of 1.1 across the whole band. Last time I analyzed one it was about +/- 700 KHz up to 1.9 SWR across the 11 meter band with only a few 100 KHz at the lowest point and climbed up from there.
Gee whiz, you guys act like 20’ is a problem.
Took me 27’ and none to spare (I’m kidding. Mainly as it’s a Peterbilt I’m re-doing).
Took me 27’ and none to spare (I’m kidding. Mainly as it’s a Peterbilt I’m re-doing).
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