John, your post was excellent, but you should not discourage people from
placing their antenna as far away from a house (within reason) as possible.
I have had multiple occasions where I took a shortcut and placed a small
mast on top of my house and hung the center of my dipole from it. The
result was RF in the house - not necessarilly in my rig, but in the radio,
the tv, the telephone, the heating system, etc. It was also in the
neighbors' stuff. I moved the same antenna about 20m from the house and
there were no more problems.
73
Rick
-----Original Message-----
From: tentec-bounces@contesting.com
[mailto:tentec-bounces@contesting.com]On Behalf Of N0KHQ@aol.com
Sent: Thursday, April 22, 2004 7:46 AM
To: tentec@contesting.com
Subject: [TenTec] Re: RFI - Orion and any other SDR Rigs
There are multiple past posts on this subject.
For a short reminder:
The keying line running from the rig to the amp should be rapped around a
toriod cube (from Radio Shack) as many times as possible.
Install a T-4 Line Isolator from Radio Works at the rear coax connector of
the rig. This device creates a very high resistance to RF and will help to
force
any stray RF on the coax shield to ground.
There should be only ONE point for your ground connection going outdoors to
the ground rod, assuming you are using an antenna tuner the ground wire will
be
tied to the tuner ground lug. The wire going outdoors should be a length of
RG-8/PE. At the tuner you will connect only the center conductor, at the
ground
rod short the center conductor to the shield and connect it to the ground
rod. This will effectively help to drain any RF that may be on your
equipment to
ground, the length of this coax should be kept as short as possible. Solder
if
possible and make sure that this connection is water tight.
If you make the MIC connector modification to the rig. (mic connector
grounded to chassis) then you will want to install a .01pf cap from the mic
audio +
pin to this ground. The mic cable shield will ground at the rig mic
connector.
Lastly, buy and install a TT-1251 RF Counterpoise Tuner. This device works!
It allows you to resonate your ground system on the band/frequency that you
are
using (no harmonics).
SDR's are a different breed of rig (they are also the wave of the future).
Special grounding techniques and power requirements are required.
Your saying to yourself, "my Kenwood, Icom or Yeasu never did
this"........well those rigs are not computers.
What ever you do, dont think that the rig is at fault.........its not the
rig.........its your station system installation thats at fault.
As for moving your antenna as far away from the house as you can get
it.........thats a bunch of BS. If that were the case, you wouldnt see any
antennas on
radio or television stations. And they are running a heck of a lot more
power
than you are.
Start doing some reading on Broadcast Engineering.
Recommending reading: ON4UN "Low Band DXing" a great (real) book.
If you like, reply to me directly and I will email to you complete
construction details of the "Tunable Buried Radial System" that I use here.
Other TT users have installed this system and have reported great results.
Not only does it totally remove any RFI but it also adds 3db to 6db of gain
to
your present antenna gain.
OR
You can give up, send your Orion back to TT and I'll buy it or someone else
will.
The Orion is a great rig.........and its only going to get
better.........just takes time.
73
John / N0KHQ / St. Louis
Always on 18.130
Antennas:
You can build 'em better than you can buy 'em
Please visit the sites below:
http://www.hamuniverse.com/17mcoaxmox.html
http://www.cebik.com/n0khq.html
http://www.ssb-audio.com/forum/
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