GM George,
The advantage of this type of delta loop is, at low heights, the loop fed
vertically polarized has a lower radiation angle than the dipole. The dipole
will have to be raised a lot higher to match its radiation pattern. The loop
is also more broad banded. Its advantage over a quarter wave vertical is, you
don't need to put lay a bunch of radials, which often can be a nuisance.
As for how to feed it, well I have been feeding loops like this for 35 years
and they have been giving me outstanding results. That does not mean a perfect
match but good enough to use without a matchbox. Of course the impedance
varies with height above ground.
If you have a better idea on how to feed it, please share it with us.
I'm always happy to learn something new.
My source of information on how to feed this type of antenna is from DL1BU (SK,
and ex- chief technical Engineer of the DARC) in his article on loops, printed
in the 1979 issue of CQDL magazine, page 154.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of george fritkin
via TenTec
Sent: Sunday, November 23, 2014 4:40 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] 17 Meter Antenna
Delta loops show marginal gain over a dipole (1.1db), and are much more of a
pain to erect. As far as noise no real proof that is true. And one more
thing, feeding with 1/4 wave of 72ohm is more voodoo engineering you find here
George, W6GF
On Saturday, November 22, 2014 11:18 PM, Rick - DJ0IP / NJ0IP
<Rick@DJ0IP.de> wrote:
Use a telescoping fiberglass pole.
They don't have to be very high.
25 ft. is high enough if you make the horizontal bit a little longer.
That still leaves about 7 or 8' under the antenna so that people can walk under
it.
Scott (W4PA) sells 40' poles. One of those would be perfect.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Reed
Sent: Sunday, November 23, 2014 4:17 AM
To: tentec@contesting.com
Subject: [TenTec] 17 Meter Antenna
I'm sure Gary they are the best antenna for the dollar, but not enough trees
here for support. I was raised on a farm & my late father, W4PFP & elmer, had
some serious wire antennas. I miss the real estate, but not the farming.
Reed W4JZ
Reed,
I had a 80M Delta loop up for quite a few years. It worked extremely well.
Very quiet. It was fed in the corner with 75 ohm coax, then 50 ohm to the
shack. My matching piece of 75 ohm coax was abt
46.5 feet long (1/4 wave x velocity factor of the cable). I'd put another up
but all my trees have grown up.
Gary - KN0V
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