----- Original Message -----
From: "Robert Ladden" <[email protected]>
To: <[email protected]>
Sent: Saturday, October 15, 2011 6:07 PM
Subject: Re: [Drakelist] Receiver protection lamp
The TR-3/4 had a fuse lamp between the receiver and
antenna to protect the receiver. Since these were mobile
rigs the large whip antennas could hit light fixtures in
garages (my theory).
73,
Bob WW3QB
More likely to protect the input circuit if someone else
fires up a tranmitter nearby, it would also protect the
input from static accumulation from friction on the antenna
and from driving through a lightening storm. Serves a
similar purpose when used in a fixed location. The lamp is a
twin-post lamp with similar characteristics to a No.47 but
the base arrangement has less reactance at radio
frequencies.
I managed to pop one while trouble shooting a TR-4 and
had trouble getting replacements locally. Keeping a spare
available is a good idea even though they are likely to last
forever. If the TR-4 receiver seems dead and its nothing
else the lamp is worth looking at. If its open or the
contacts are dirty the effect is of no antenna being
connected.
--
Richard Knoppow
Los Angeles
WB6KBL
[email protected]
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