-----Mensaje original-----
From: Fernando González, EC1CT
Sent: Wednesday, October 28, 2015 4:38 PM
To: Herbert Schoenbohm
Subject: Re: [TowerTalk] Strange happening with 10 Meter Beam
Hi Herb,
I´m owning the same antenna for the last 20 years or more on 10 meters. It´s
an original LJ105CA (not MFJ) bought new and been using it extensively
during all this years. I have a separate
station for 10/6 meters with 2 towers. The antenna is at 40 ft in its single
guyed tower. I have a 4 SteppIR at 60ft in a self supported tower located
200 ft away that I use it for comparision.
The HyGain long john is a GOOD antenna. I never had a problem with it appart
of two BN86 burned baluns that were replaced with a BN4000 (no problems
since then at 1kw). The SWR is flat as you stated all across the band (from
1:1 on 28.450 to 1:6 on 29000). If you look at the manual you´ll see
different lenghts for different purposes. Mine is settings for best forward
gain and the gain is well whithin the specifications on the manual as well
as the front to back ratio. In comparision with the SteppIR which is higher,
the HyGain outperforms the SteppIR 75% of the time which 10% of the tiime
the signals being equal on both antennas. 15% of the time the SteppIR seems
to ¨receive and transmit¨ better than the HYGain (all results meassured with
my own ears and the operators on the other side, smeter readings and qsb
appart). I´m pretty sure you must be having something wrong with the
antenna and I would suggest to move back to the original settings (you got
the manual online) and be sure you´ll love the antenna for ever. 73s
Fernando EC1CT - KD0IGJ
ec1ct@esbesaya.com
-----Mensaje original-----
From: Herbert Schoenbohm
Sent: Wednesday, October 28, 2015 2:30 PM
To: towertalk@contesting.com ; Yuri
Subject: [TowerTalk] Strange happening with 10 Meter Beam
For the CQ WW I put up a 5 Element HyGain 10 meter beam(LJ-105CA) I
double and triple checked all the element lengths and the VSWR is so low
across the band it really excited me. It also scares me a bit as up in
the air the VSWR is never above 1.3 to 1 from 28.0 to 29.5. The problem
is that signals are very weak on non existent when compared to my 3
element quad at 80 feet which was the only antenna that worked on ten
during the contest and after.. ( The yagi is one a separate tower at 50
feet)
Here is what I have on it.
New piece of LMR-400 with good connectors fed directly to the insulated
(Hy Gain cup type) director.
The beta rods were missing so I use the direct feed to each director.
(OWA type matching idea)
I moved the first director slightly closer to the driven element to
obtain the correct match at 28.4 Mhz
Everything looks good but the 10 meter antenna is about as good as a
dummy load.
I have been building yagi's for over 50 years and have never had such a
strange problem. Even a beam with half the driven element missing after
a hurricane could hear something but what I have up can't.
Before I take it down I ask if anyone else had experiences with this
problem. It must be something very simple but I have checked everything
I can think of and still no joy here.
Please let me know
Herb Schoenbohm, KV4FZ
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