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My First Attempt At A Mobile Antenna
- Thread starter HomerBB
- Start date
Look closely enough on the larger photo and you'll see the center conductor is attached to the terminal screw at the bottom of the shaft, and the shield is connected to the angle mount. The vertical is insulted from the angle bracket.
Each of them has seemed to perform well, but that is a relative answer. I am going to run a test on transmit and receive of each one against the other and against a K40 bottom load mag mount I've got and a 102" SS whip.
After that i may be able to provide you with better answers.
After that i may be able to provide you with better answers.
I've begun the process of making comparisons between the several models of the antennas I built to each other, a K40, and an straight 1/4 wave whip.
First of all I had to put a reliable means of mounting the antennas on the roof of the SUV with quick change capabilities. Where this antenna is attached to the mount on these two photos I put a 3" piece of PVC into which I dropped each antenna shaft with a set screw through the PVC wall into the bottom of the antenna shafts. To this set screw I attached the coax center conductor. Here is the mount:
Next I mounted the antennas one after the other on the roof and reset the SWR across the band capabilities of the SuperStar 3900 in the mobile. I was dead keying 3/4 watt, swinging around 12 watts PEP; no kicker online. I was talking with a base station 10 miles from me, I will do a 15 or 20 mile base station later when I can get them to cooperate for a little while. The antenna on the base is a vertical groundplane with the coax connector at 70' above ground. He was talking to me with 2 watt dead key. I do not know what his PEP is at this time.
The antennas are a K40:
a whip:
By order of build -
#1 homebrew:
#3 homebrew (#2 was rewound into this one):
#4 homebrew:
#5 homebrew:
Here are the results so far:
What I will have to do, perhaps tomorrow, is add the overall dimensions of the various antennas in an additional post. It got dark on me today..
First of all I had to put a reliable means of mounting the antennas on the roof of the SUV with quick change capabilities. Where this antenna is attached to the mount on these two photos I put a 3" piece of PVC into which I dropped each antenna shaft with a set screw through the PVC wall into the bottom of the antenna shafts. To this set screw I attached the coax center conductor. Here is the mount:
Next I mounted the antennas one after the other on the roof and reset the SWR across the band capabilities of the SuperStar 3900 in the mobile. I was dead keying 3/4 watt, swinging around 12 watts PEP; no kicker online. I was talking with a base station 10 miles from me, I will do a 15 or 20 mile base station later when I can get them to cooperate for a little while. The antenna on the base is a vertical groundplane with the coax connector at 70' above ground. He was talking to me with 2 watt dead key. I do not know what his PEP is at this time.
The antennas are a K40:
a whip:
By order of build -
#1 homebrew:
#3 homebrew (#2 was rewound into this one):
#4 homebrew:
#5 homebrew:
Here are the results so far:
What I will have to do, perhaps tomorrow, is add the overall dimensions of the various antennas in an additional post. It got dark on me today..
It seems to have broadened a little more on the top of the SUV as apposed to the front fender. It's still pretty long; maybe too long for the roof.
Very good work Homer. The recap is very concise and easy to understand.
Trying to get folks to cooperate with such test to compile such reports is difficult and has been my experience also. It takes time...which most don't want to spend exchanging signal reports.
This line up and report would make a great addition to a profile album and then the work won't get buried over time in this thread. Some of the images might also pop-up on the front page from time to time so new and other interested members can see what you do.
Trying to get folks to cooperate with such test to compile such reports is difficult and has been my experience also. It takes time...which most don't want to spend exchanging signal reports.
This line up and report would make a great addition to a profile album and then the work won't get buried over time in this thread. Some of the images might also pop-up on the front page from time to time so new and other interested members can see what you do.
I'll measure them all again in a little while. I'm drinking my coffee to clear the sandman out of my head . . .
Since antenna #1 is practically flat across 11 and 10m; I wonder how it does on 12m? The RCI-2950 and 70 are 12m radios; if it could work there as well, you may have something there that others might be interested in buying. It is ~7 ft 8 in in height; not too bad for an antenna that matches so well. If you have access to a MFJ-259 antenna analyzer, you might be able to plot the x value too.
Could be quite interesting.
Could be quite interesting.