Thread: HF is Smokin
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Old May 1st 12, 05:03 PM posted to rec.radio.amateur.antenna
Jeff Liebermann[_2_] Jeff Liebermann[_2_] is offline
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First recorded activity by RadioBanter: Jun 2007
Posts: 1,336
Default HF is Smokin

On Mon, 30 Apr 2012 12:18:29 -0400, John Ferrell
wrote:

I put up a fan inverted -V cut for 80-40-30 a while back just to test.
I use a tuner, as long as the transmitter likes it, I like it.


If it's anywhere near a 1/2 wave dipole, a fan dipole shouldn't need a
tuner. I've built two fan dipoles over the years. Since everything
affects everything else, I spent far too much time adjusting the wire
lengths. I eventually settled on a trapped dipole, which was easier
and worked the first time. Either antenna would work for me except
for the length. I don't have the room for a proper 80 meter dipole.
For the immediate problem, I'll be happy if I can get on 20 meters
(PSK31) and 10 meters (radio club net).

It seems to work well on all bands I have tried. Although I prefer my
manual MFJ tuner, the internal tuner in my TenTec Jupiter seems to do
OK.


Antenna tuners can be quite lossy. Have fun with this Java app:
http://fermi.la.asu.edu/w9cf/tuner/tuner.html

Do you have a field strength meter? Find a location in the pattern
and as far away as practical. View the meter from your operating
position using binoculars or a telescope. Try your fan dipole
directly to the 50 ohm output of your transmitter. Hopefully, the
VSWR will be less than what it takes to trip the VSWR protection
circuitry. Now, install the antenna tuner and try again, keeping the
RF power at the same level. If you have problems leveling the RF
power, use an AC powermeter, such as a Kill-a-Watt, to measure the AC
input power consumption. When I did the same test, the antenna tuner
always had noticeably less TX signal strength.

I am not a contester, a DX hound or a perfectionist but I do like
to spend a little time on the air.


I spend more time inside the radios than in front of them.

It will keep you on the air and give you time to decide where you want
to go from here with out undue pressure!


The answer for me was supplied by outside influences. A mess of work
arrived at my shop, so I'll be too busy to do antennas for a while.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558