Mark,
I just read the lengthy comparison of the RF-1B to the Wellbrook ALA-1530L.
Not a huge difference but the win certainly goes to the RF-1B. However I
did read an interesting tidbit near the end, which might be important for
some users.
There is a difference in how the loops connect to their pre-amplifiers.
The ALA has a box integrated into the loop. It is convenient and one less
chance of failure.
The RF-1B connects with a short stub of coax. One more point of possible
failure, but easy to fix.
But there are other consequences:
Now imagine one lives near to a very strong broadcast station.
With the Wellbrook you might have trouble, whereas with the RF-1B you could
insert a 1.8 MHz highpass filter between the loop and the amp. There is an
excellent HPF available from Dunestar for $80 but it's kind of overkill. I
have a homebrew filter (preselector) that would do the trick. This is a
HUGE advantage in favor of the RF-1B over the Wellbrook.
I also liked the feature to switch it in and out using the AMP-Key line,
though I much prefer placing my RX antenna in the transceiver's RX line and
not even in the TX line. The RF-1B has this feature, the Wellbrook does
not.
BTW, I just checked with Jack (K8ZOA) to see if he had ever tested the loops
against a full size dipole.
Here is his reply:
"No time to write up the full report and some of the wire antenna data
needs to be re-collected so it would really mean a complete new test that
takes a couple months to run and analyze. -Jack K8ZOA"
Now "that" is the test I would like to see.
Further, I would like to see how either of these broadband magnetic loops
compare to a tunable magnetic loop.
Though the tunable loops are a pain to use in a contest due to needing
constant re-tuning, they do have the advantage of acting like a bandpass
filter, thus reducing the strength of all out-of band signals, including the
noise.
There is no question that magnetic loops perform better than our typical
dipoles or verticals in the noise department.
I just question whether we must pay $500 to get this benefit.
My low cost approach will certainly be as good, but requires constant manual
re-tuning.
So I guess the real question is, how much more is a broadband solution worth
than a manually tuned solution?
73
Rick, DJ0IP
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Mark
Luhrman
Sent: Sunday, September 22, 2013 3:10 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Value of RX Only Antennas
First of all the loop is an outside loop. It hears better than my Hi-Z 2el
vertical rx array most of the time much quieter. I am living in a suburban
neighborhood. Noisy environment. If I didn't have that loop I would not
have heard many stations on 160. And the average ham could not build this
type of loop. When I bought the loop it was $400, not including 200 feet of
rg-6 quad. Thec $500 includes the coax now.
Sent from Yahoo! Mail on Android
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