Hi All,
> I think you'll be happier with the 775. The R4C has relatively low dynamic
> range and TOI compared to today's transceivers. Get competitive with it
> (ie, contesting) and it'll fold early. But, has really, really low
> synthesizer noise:)
I owned a brand new 775DSP one year ago.
Your mileage may vary, and I don't intend to start a long thread, but
anyone with a 775DSP should carefully check for spurious
emissions caused by the unused VCO (even when off) "leaking
out" on the transmitter. It also "leaks in" on the receiver on strong
signals, especially with close spacing.
Mine also had a 350 watt transmit spike (no matter what power the
drive was set at). That can triggered PIN diode failure or even arcs
in an external power amplifier.
> As a point of interest, does anyone know of anyone measuring receivers
> with close signal spacing, oh, for example, INSIDE the first IF crystal
> filters? Seems to me, first order, that the ARRL method of using 20KHz or
> 50KHz spacing has little value on 160/80. Our interferers, that is each
> other, are inside the roofing filters.
My FT-1000D fell totally apart with close test spacing, as does a
stock R4C older than mid 18,000 serial numbers.
I cured the FT-1000D with less than one dollar's worth of
components. The 775 I had was unfixable without extensive rework
of the VCO switching scheme.
73, Tom W8JI
w8ji@contesting.com
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Problems: owner-topband@contesting.com
|