Hi Joe, Laurence,
I have an FT857D (a wattier 817) in my car, and its deafness is of heroic
proportions. If I were asked to come up with something that worked so well at
HF but so dismally at LF, it'd be a struggle. It can't hear an NDB unless it's
within about a hundred yards of it; absolutely amazing.
So similarly, I use an Altoids tin containing a 500kHz low-pass filter and two
series'd preamps to render it useful. Each preamp's configuration is based on:
http://w7iuv.com/preamp.jpg
only using FT50-J cores instead. It is broadly similar to a preamp by our very
own Mr. Rusgrove, I believe the details of which are on John, W1TAG's site.
Cheers,
Steve
01/04/05 20:20:04, Joe Craig <[email protected]> wrote:
I use a "Burhans" preamp with my FT-817. The measured gain
was 30-35 dB. Like the G0MRF version Laurence is using,
it uses a BJT and FET with a somewhat enigmatic biasing
arrangement for the BJT.
The 817 is very deaf without a preamp.
73
Joe VO1NA
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