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Wellbrook question
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September 29th 06, 01:18 PM posted to rec.radio.shortwave
Steve
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First recorded activity by RadioBanter: Jul 2006
Posts: 1,324
Wellbrook question
wrote:
Has anyone had a "bad", as in less then stellar performance, with a
Wellbrook ALA 1530
loop antenna?
Given the almost sacred refference the Wellbrook is held in I have
debated asking
this question. I have a ALA 1530 that is part of a trade that I am
looking at and
guys I just don't get it. This antenna is reputed to be the cat's meow,
but I have
found it marginal at best. A north country active antenna is nearly
it's match
and the 3rd harmonic of a local MW (770KHz) is S3 on the Wellbrook. A
Lankford Active Dipole stomps it in gain, IP2 and IP3 and for
directivity.
I am wondering if this antenna is defective or if it is a case of the
Emperors New
Clothes. I have tried loops several times in the last 30 years and
always give up
becuase I have never found the reported imunity against local QRM to be
true.
I am building a copy of the WL1030 (
http://wl1030.com/)
, but I don't
understand
the fascination with loops. What am I missing?
For MW DX "big" air loops make sense. Good directivity to null out an
offending
signal. I notice Ron Harding uses McKay 100E with a phaser to achieve
good
nulls. For HF the sky wave "smears" both the desired and unwanted
signals
making a null very iffy.
Receivers used in this test:
R2000
R8B
R390
R392
The R390 and R392 where not tested at my home but at a friend's home
where I have them stored. While I like both the R390 and R392, they are
somewhat awkward to rapidly tune from one frequency to a wildly
seperated
one.
Terry
One thing you might do is check the cables connecting the different
components of the Wellbrook. At one point I noticed that my loop wasn't
performing as I thought it should and I discovered that the cable
connecting the receiver to the antenna interface had a poor connection
where it meets the interface box. The intermittent connection became
obvious as soon as I jiggled the cable a bit.
Also, where do you have the loop situated? In my experience the
performance of the loop is seriously degraded when used indoors.
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Steve
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