The delta loop is around 100 ohms. I run one on 30 meters and it works
great. I use a 1/4 wave of 75 ohm cable then 50 ohm cable for an
excellent match to 50 ohms.
Carl Moreschi N4PY
58 Hogwood Rd
Louisburg, NC 27549
www.n4py.com
On 11/23/2014 12:59 PM, Rick - DJ0IP / NJ0IP wrote:
George,
Some hams are into the sport of amateur radio for the technical aspects alone.
Others are in it for the sake of communicating.
Those of us who are in it for the sake of communicating, judge the value of an
antenna for its ability to help us reach DX destinations that we have trouble
reaching with some other antenna.
In this respect, this simple and cheap antenna stomps a low dipole (at least on
40m where I have used it the most) and holds its own against a vertical with 32
or more radials.
This is not speculation. It is my experience using this antenna.
I have erected this antenna just for contests at least a dozen times, at
several different QTH's and the results were always the same. The standard
antenna normally in use was a dipole about 40 ft. high.
With this antenna, from Germany, and a couple other countries where I have
operated with it, stateside, JA, VK, etc. are typically 1 to 2 S-Units stronger
than on the standard dipole, all the time. I found it much easier to work
these stations with the loop than on the dipole.
This thread is about suggesting a good antenna for 17m.
I have suggested one, including how I built it.
You have poo-pooed my suggestions a couple of times without contributing
anything useful towards the original problem: helping improve the signal on
17m. I welcome critique, but then I kind of expect an explanation to follow.
I'm not a crack-engineer; just a ham with a lot of experience and nearly 20
first place certificates in CQWW DX - most as a team member (MS or MM), but
several as a single op working alone.
In order to place high in a contest, you have to use antennas that work well.
This antenna has worked well for me and has helped enable me, as well as my
team to win contests.
I welcome any suggestion you may have for improving this one or for something
which works even better.
Thanks.
Now to answer your question. "No".
Although I have two antenna analyzers, I did not own one the first few times I
built this antenna 34 years ago. I only measured the SWR and then used it
successfully in contests.
The next time I build it, I will attach a half wavelength of feedline to it and
measure the impedance. It's kind of difficult to physically reach the
feedpoint. Will be interesting to see what it shows.
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 6:15 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] 17 Meter Antenna
Really, did you measure the impedance at the feed point?
George, W6GF
On Sunday, November 23, 2014 8:50 AM, Rick - DJ0IP / NJ0IP<Rick@DJ0IP.de>
wrote:
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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