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Old 02-12-2016, 02:32 PM   #1
N4MU Papi
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Default Tarheel Locations - Experiences/Ideas?

I had placed this in another category...forgot this one...sorry.

Here’s a question with no cut and dried answer I know but I sure would like your best guess on the results.

Picture a Tarheel 100 sitting in the center of an 8X8 foot metal storage shed. All metal…roof too (flat roof). The antenna base would therefore be about 8 feet off the ground just over the metal roof. What are my chances of it loading? Any improvement using a radial kit (from the antenna base and draped over the shed, then down the sides and then out along the ground surrounding the shed? Would a capacitance hat improvement the loading in this situation? BTW, I run 500 watts.

I know this is weird but I’m getting into a situation where it may be the only possibility. I may also be able to just plop the antenna in the ground a few feet away from the shed and use conventional radial kit but if I can raise the base to the shed roof it would physically be better. (And hidden better)

Just wondering if anyone has ever heard or seen of anything similar. Thanks!
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Old 02-12-2016, 06:58 PM   #2
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Tarheel says to ground mount it with radials. However I think it will work just fine on your roof. They will tune pretty much where ever you put it the problem comes when you try to contact some one! The bottom line cars/truck are not real good ground planes any way. I have a HS mounted at the rear of my camper up maybe 7-8' it's roof is aluminum and frankly it works great. A cap hat may help the lower bands all though mine works fine on 80 meters.
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Old 02-14-2016, 04:22 PM   #3
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It's my understanding that most Tarheels are in North Carolina.
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Old 02-14-2016, 06:50 PM   #4
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Quote:
Originally Posted by NN5I View Post
It's my understanding that most Tarheels are in North Carolina.
Well some have made it to Maine but that was after careful consideration.
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Old 03-28-2016, 10:00 PM   #5
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Default tarheel info

After having the lil tarheel II in a box in a corner for a month, finally got around to starting to assemble it.

For now, I just set it up here inside the apartment, not to actually work anything, just to assemble it and test.

I also purchased an AA-30 antenna analyzer ( Made in the Ukraine). What a nice piece of equipment.

All i do is run a SWR scan and see how many turns on the antenna motor gives me what resonant frequency (approx, Im indoor and too many metal objects around). I can calibrate it accurately later when outside, I was just checking function and wiring.

So, in another month I should be able to figure out the mount on the trailer, and I'll be ready to get on the road at the end of May.

PS- 66 degrees today, another snow storm tomorrow night.
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Old 03-28-2016, 10:36 PM   #6
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Quote:
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... purchased an AA-30 antenna analyzer (Made in the Ukraine). What a nice piece of equipment.
Yes -- the RigExpert stuff is the best. I have an AA-230 Pro that I bought about five years ago, and can't imagine being without it. Nothing else comes close.


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Originally Posted by ke0me View Post
PS- 66 degrees today, another snow storm tomorrow night.
Sunny in Tallahassee today, about 75 degrees, light variable wind. But it poured rain for four previous days runnin' -- as we say here.
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Old 03-29-2016, 09:29 AM   #7
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Bird AT 100 and AT 400 nice graphic analyzers.
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Old 03-29-2016, 09:38 AM   #8
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Quote:
Originally Posted by ke0me View Post
After having the lil tarheel II in a box in a corner for a month, finally got around to starting to assemble it.

For now, I just set it up here inside the apartment, not to actually work anything, just to assemble it and test.

I also purchased an AA-30 antenna analyzer ( Made in the Ukraine). What a nice piece of equipment.

All i do is run a SWR scan and see how many turns on the antenna motor gives me what resonant frequency (approx, Im indoor and too many metal objects around). I can calibrate it accurately later when outside, I was just checking function and wiring.

So, in another month I should be able to figure out the mount on the trailer, and I'll be ready to get on the road at the end of May.

PS- 66 degrees today, another snow storm tomorrow night.
I can tell you the motors drift after power is lost they will be close but it usually takes a tweak to get the SWR spot on. I use a turns counter controller and usually have to tweak it when changing bands. It takes 20 turns to advance one inch so a couple of unregistered turns will effect the SWR.
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Old 03-30-2016, 07:15 PM   #9
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Default tarheel tests - unscientific

I was doing a test inside the apartment with minimal ground and I noted how much difference there is as you tune down in frequency. I do have a frequency counter so that really helps.

for example,
10 meters 4 turns from park
15 12
20 28
30 40
40 80
80 240

I know this is not accurate compared to when I get outside, but it is interesting to me to see how much additional turns are required (i.e. more loading coil turns) as you go down in frequency.

Also, with the ant analyzer, I can change the range and frequency of the swr scan with +/- keys, and don't have to reenter frequency and range. Really easy to use.

Needless to say, the lowest swr on each band was nowhere near a 50 ohm non-reactive load. The best was 40 meters, got a 1.7 SWR, Z= 84 - j8.6

Cant wait to get outside and get it into open airspace!!
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Old 04-02-2016, 10:56 PM   #10
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Default tarheel on a balcony

Finally a nice day and no major chores to do.


Took the Tarheel outside (about 8 feet off the ground), u-bolted the pipe mount to a wood balcony. Ran about 8 ft of ground braid from the ground lug of the mount to the heating system water pipe, and finally, added about 16 feet of wire to the ground lug. The 16 ft wire does not touch the ground wire and is sort of an "L" shape.

Using the antenna analyzer, great results. I only checked 40 and 20 meters due to time. lowest SWR were under 1.5:1 on both bands.

Inside, I could actually hear stations! Guess it helps it is also SSB Sprint contest weekend.

Main reason I did the test was to get a better feel for how many turns are needed for a specific band, and effect of close by metal objects, of which there are many. Tuning on the higher bands is very tricky, like maybe one turn moves the center freq 250 KHz (or is it kHz).

So, now I'm looking forward to a nice warm weekend when I get out and design the mount for the trailer and figure out how to run counterpoise and/or radial wires on the trailer.
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