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Re: [IRCA] DKAZ
Michael: Sounds like you're well on the way!
One thought: You probably don't want to hang a shack ohmmeter across the
D-KAZ Vactrol to read real-time null resistance. That's likely to upset the
nulling of the antenna since you'd be hanging a long Cat-5 pair across the
Vactrol resistance (and hence the antenna null port).
The valid way to do remote null-resistance readings would require a
momentary "push-to-read" switching of the Vactrol, between the antenna and
the ohmmeter lead-in pair.
You'd also have to factor in the resistance of the Cat-5 (although in an
ohmmeter application that should be negligible). The bigger concern would
be adding that Cat-5 pair across the antenna null-port.
At the upcoming Kansas City convention we hope to have in operation a
reversible D-KAZ...if the QRN, QRM and Hotel gods look kindly upon us.
Cheers!
Mark Durenberger
-----Original Message-----
From: Michael Yule
Sent: Wednesday, August 31, 2016 5:49 AM
To: irca@xxxxxxxxxxxxxxxx
Subject: [IRCA] DKAZ
Hi everyone - thanks to the help I received from Colin Newell, Nick
Hall-Patch, Mark Durenburger and others, the DKAZ is now up and operative.
Not a trivial antenna to assemble and get going! I thought that it would be
best if I started with a basic one (non-reversible) and then added
reversability later if I want. All the interesting stuff is off one end
anyway since I am at the end of the continent. The antenna is 'pointed' at
about 60 degrees which should take in Europe, the Middle East, and North and
West Africa. I did some null testing a few minutes ago and with Colin's
Vactrol was able to drop a couple of stations mid-band about 40 dB as
indicated by the IF Spectrum of the ELAD.
I ended up running CAT5 to both ends (250ft to the Vactrol, 400ft to the
other end). I used 9:1 transformers at the antenna and at the house and the
amp is inside. I also ended up replacing the BNC jacks on the Vactrol unit
with banana jacks, which are easier to use coming off the antenna and with
the CAT5. I have a bunch of spare pairs of course, so when I decide to add
relays it shouldn't be that difficult. I'm thinking of using one of the
pairs going to the Vactrol to feed an ohmmeter in the house so I can see
real time what resistance is being inserted, but for now I just have the
pair hanging in the breeze so to speak.
One of the issues I had was how to get the cables into the house without
drilling holes in the walls or disturbing the aesthetic sense of my wife - I
also have a BNC termination for an ALA1530 and a N termination for a VHF log
periodoc I use for FM, so a total of at least 4 cables had to come in. I
also had to consider that it gets a little chilly here in the winter and so
couldn't simply close the window (it slides up and down) on the cables
because of the cold air getting in. What I did was get a piece of 3/8" Lexan
the width of the window and 6" high and put bulkhead connectors for the BNC
and N cables and holes for the other cables. I sealed it at the top and
bottom with the weatherstripping used for storm doors and it seems at this
point to be draftproof and since it's clear it looks just like the window,
and there's plenty of space to add other bulkhead connectors or pass through
holes when the antenna farm expands :-). I thought I'd pass this on in case
anyone else was struggling with the same issue.
Anyway, we'll see what happens in a few hours! Thanks again to everyone for
your help and suggestions.
Michael
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_______________________________________________
IRCA mailing list
IRCA@xxxxxxxxxxxxxxxx
http://montreal.kotalampi.com/mailman/listinfo/irca
Be sure to register now for the Joint DX Convention
Kansas City, September 9 to 11. Hotel space is filling up.
Registration info:
http://www.nrcdxas.org
Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers
For more information: http://www.ircaonline.org
To Post a message: irca@xxxxxxxxxxxxxxxx