[TenTec] Orion freezes due to RFI??

[Rick Westerman]

Henry,

That sounds great.

Do you have the possibility to draw a schematic and scan it in as
a jpg file?
Or perhaps as a PowerPoint file?
Or worst case, could I trouble you to mail it to me.
If I have the circuit, I'll gladly convert it to a file and
re-distribute.

Thanks.

73
Rick

-----Original Message-----
From: tentec-bounces at contesting.com
[mailto:tentec-bounces at contesting.com]On Behalf Of Henry Gardiner
Sent: Monday, December 15, 2003 11:06 PM
To: tentec at contesting.com
Subject: Re: [TenTec] Orion freezes due to RFI??

     Regarding RF pickup on the Jupiter via the speaker jack:
     My RX-350D is said to be the receiver section of the
Jupiter.  My
problem was the transmission of rf energy out of the receiver and
into the
very nearby antenna.  The antenna itself is simply a wire on the
end of a
piece of coax.  And no proper RF ground yet!  While I have this
pickup
problem, I know of one other ham who doesn't because he has a
better
antenna and ground system.
     So, for the sake of another solution, I present the
following:
     I installed bypassing for the speaker jack.  0.1 uF disc
capacitors to
ground from each of the three pins on the jack.  Also a
three-winding
common-mode blocking transformer.  I used three lengths of 22 ga
magnet
wire twisted together at a convenient rate.  This was wound
through the
FT50-72 core 5 times. This was interposed in the circuit between
the jack
pins and the nearby pcb connectors, using the same polarity in
each case.
     And, amazingly enough, the audio amp doesn't break into high
frequency
oscillation.

Henry Gardiner AC5LA


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