I burned out a couple of antenna input coils in my
trusty old TS-830's. Strangely, the 160M input coil
(which is in place for all bands) is in a 7mm 'can'
which forces the use of very fine wire, the the other
band coils in 10mm cans. The operating manual
warns against input signals in excess of 7 Volts.
I remember seeing a warning on the back on an old
Collins 75A3 that said "Do not exceed 50 Volts" at
the antenna input. You could momentarily dump
an exciter into that radio without hurting it!
To protect my 830's, I now have 'protection boxes'
in series with the RX Antenna line (available through
the transverter plug). These boxes consist of a
series 2W carbon composition (non-inductive)
resistor followed by a pair of 4 high PIN diode
stacks of opposite polarity. Any low capacitance
high speed switching diode should also work.
Unfortunately, carbon composition resistors are
hard to find these days but other non-inductive
resistors are available.
de Tom N4KG
>>>>>>>>>>>>>>>
On Sat, 06 Jan 2001 20:35:34 -0500 M K Miller <qcs0041@lexcominc.net>
writes:
> As a result of a " senior moment ", I just fried the receiver front
> end
> of my FT-1000D. I was transmitting with the other rig on an antenna
> which is spaced only 15 feet from the main slopers, which of course
> were
> tied to the FT-1000.
>
> I looked back into the archives, but find no notation of anyone
> doing
> the same dumb thing. Has anyone had the misfortune to inadvertently
> zap
> a 1000 receiver in this manner, and if so, how bad a job is it to
> repair
> ?
>
> Thanks, 73,
>
> Kent -W4MKM
>
>
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>
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