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Author Topic: Transferring HS-1800 from Tripod to car  (Read 1172 times)

Posts: 273

« on: August 20, 2008, 11:51:37 AM »

Because of CCR Restrictions - I need to move my HS-1800  from tripod in backyard - to my Toyota Corolla.( outside front of the house ) - to use only as a base station ( not mobile) ( My rig and amp are in the house )
My plan is to purchase the High Sierra Mounting Bracket, and the 2 inch layback receiver hitch adapter. - then have a 2 inch receiver hitch installed. OR - can I use the 1 1/4 inch  Huh
 My Question: re: creation of a good Ground Plane for mobile antenna to work well !!
       Just exactly where does the copper ground braid connect??? - from the screw on the mounting bracket ? - to just exactly where on the car body ??
Do I need to have a screw bolted somewhere on the metal part of the frame of car ?? - where exactly ?
        Do I need to bond any other parts of the car - with a ground braid ??
How to best achieve a good ground plane ?
Many Thanks - I am new Ham and a restricted one at that !

Posts: 10248


« Reply #1 on: August 20, 2008, 03:53:31 PM »

You've got a lot to learn. Ground straps are not a substitute for a decent ground plane. Unless of course, they're long enough to be radials. With respect to mobiles, this is a bit absurd.

Trailer hitch mounting locations, although often used, are about the worse case scenario with respect to efficiency. Since a mobile installation is already a compromise, why compromise it worse?

Rather than go through all of the scenarios you're liable to encounter, just go to my web site and start reading.

Alan, KØBG


Posts: 273

« Reply #2 on: August 20, 2008, 06:18:30 PM »

Thanks Alan - looked at your site - a major contribution to ham radio - thanks !
        It looks like to create a sufficient ground plane for the HS-1800 on a car - many multiple ground straps are needed - for sufficient bonding. I am afraid that the cost to have installed - would be prohibitive for me.( I am not mechanical) -
Looks like - Just using 1 ground strap from the mounting bracket to the metal frame of car - would be insufficient to produce a decent ground plane.
Right now - using 12 radials with a tripod - antenna performs quite decently. I am afraid you are right Lon, that it would not be as good on the car.
Since I got into Ham radio - to "work the world" - I suppose I should just wait for the sun spots and operate in stealth at nite. I want to talk with the UK and India for example. I can't hear them now.

Posts: 194

« Reply #3 on: August 21, 2008, 06:05:21 AM »

Just a few thoughts. First; ANY antenna is better than none. ANY antenna is better than a dummy load -- the ultimate in low SWR but not an effective radiator. So get something out there and tune it to resonance at the freq you want and go for it.

ANY mobile is a low efficiency/compromise thing. That's true and you'll hear it a lot. However they do work as seen by the many who enjoy HF mobile -- like me for the past 30 years.  So if CCR has stopped you and you can't find a stealth solution then a mobile in the drive is the next best thing. You do what you can do and you work who you work and you enjoy what you enjoy. Don't have delusions of grandure -- but don't let anyone talk you out of it either.

I use a 4 magnet "H" frame mount sitting in the middle of the roof of my F-150 pick-up with a screwdriver on it. It's narrow banded -- especially on 75M -- but works OK on 40 thru 10. So I retune if I move too far from the resonant frequency. Takes an extra half minute each tiem; but operating at resonance Vs using a "tuner" is way more efficient. Resonant radiates. Tuners "fool" the transmitter into thinking it's happy with a low SWR but don't change a thing about the antenna's charestics. From the middle of the roof it's as high as I can get it and above the sheet metal -- both are important factors. Also the radiation pattern is more symetrical since it's centered in the car's mass Vs off one side or end which is good. The 4 magnets -- 5" diameter each -- hold it firmly and are a "capacitor" which couple it to the car body. The car body is a "capacitor" that couples it to the earth. Inefficient -- but it does work.

You will work people and have fun. The sun spots will return and you will work some DX. I have had a 90 minute QSO with a JA on 20 SSB (barefoot -- I've never had an amp) as I drove I-80 in Iowa. Have worked some rare DX on 15. Worked anywhere/everywhere on 10 when it's open. I can usually check into the county hunters or maritime nets on 20 and MIDCARS, SCARS, etc. on 40 even now with poor propagation.

It can be done; just not as easily as a fixed antenna up high.
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