Les,
Forgive me for "butting in" on this topic!
If you phase identical antennas, the array gain is proportional to the
antenna spacing. Hence, the gain of the SAL-30 drops off too much on the AM
band. One also has to contend with pattern degradation with close proximity
surrounding buildings, power/phone lines etc especially if the array design
doesn't allow for user control of phase/amplitude balance.
To get the best out of phasing two active whips you need ones that isolate
the RF return path from the feeder. This can be done with common mode chokes
at the antenna base plus a ground rod. You will also need at least 20m
antenna separation for the AM band.
Mark Connelly, has made some useful comments re, the Flag antenna. If you
are not into home construction of these antenna parts then have a look at
the Wellbrook FLG100LN.
73
Andrew
----- Original Message -----
From: "Les Rayburn" <[email protected]>
To: "Nick Hall-Patch" <[email protected]>; "Mailing list for the International
Radio Club of America" <[email protected]>
Sent: Monday, February 03, 2014 8:06 PM
Subject: Re: [IRCA] Array Solutions SAL-30
Nick,
I'm glad that you addressed this topic. I've experienced a similar issue
when phasing active whips against each other. Deep nulls are easy enough
to obtain, using the Quantum Phaser with 2 LF Engineering Active Whips,
but once nulled, the remaining signal is so low that identification of
stations underneath can prove impossible.
What is the solution to this problem? It sounds like you're saying that
bigger antennas with a greater capture area may be the only solution?
Unfortunately, that's not a great option for my deed-restricted, HOA
situation or my small back yard in general.
Any suggestions welcome. Thank you for sharing your expertise. Very
helpful to a newcomer.
--
73,
Les Rayburn, N1LF
Maylene, AL
EM63
Member NRC, IRCA, & Medium Wave DX Circle
Former CPC Chairman for NRC/IRCA
SDR-IQ,Funcube Pro, Wellbrooke ALA-1530+ loop, LF Engineering Active
Whips,
Quantum Phaser, Kiwa Loop, Palstar MW Pre-Selector
On 1/31/2014 10:49 AM, Nick Hall-Patch wrote:
Guy Atkins sent me this link awhile ago, don't know if you've seen it
Les.
http://www.youtube.com/watch?feature=player_embedded&v=f8no9r3Ufo4
That's with a slightly larger version of the same antenna I believe.
A smaller and earlier version, closer to what you might be able to handle
is here:
http://www.youtube.com/watch?v=GKBOEtkJ7yY
Problem with smaller ones, is that you may null a strong station, but
there's nothing left to hear on the channel, as you're only left with the
noise floor. An antenna with a good null is not necessarily a good
antenna. (if effectively, everything else is partially nulled also;
phased antennas usually are lossy)
best wishes,
Nick
At 06:39 30-01-14, you wrote:
New review of the SAL-30 antenna system posted at:
pvrc.org/Newsletters/feb14.pdf
I've been lusting in my heart after one of the new Array Solutions
Shared Apex Loop antennas for use in MW DXing. My lot would support the
SAL-12, but I doubt it would ever pass muster with my neighbors and
homeowners association. I'm curious if any AM DX'ers are using this
antenna, and how it has performed. See the link below for more
information.
http://www.arraysolutions.com/Products/sal_array.htm
--
73,
Les Rayburn, N1LF
Maylene, AL
EM63
Member NRC, IRCA, & Medium Wave DX Circle
Former CPC Chairman for NRC/IRCA
SDR-IQ,Funcube Pro, Wellbrooke ALA-1530+ loop, LF Engineering Active
Whips,
Quantum Phaser, Kiwa Loop, Palstar MW Pre-Selector
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