Topband: RE: dedicated topband transceiver

[Doug Waller]

I use the FT-1000MP on topband, and now, with great receiving ability.
Living in a subdivision with all aerial power lines assures plenty of local
buzzing noise on 160m.  And this winter there is alot of atmospheric QRN
hiss as well.

So when I installed the INRAD 455/ 125hz IF filter, it was not surprising to
find that it rings excessively on 80/160m.  That was until I turned off the
EDSP & turned on the notch filter.  Setting the notch knob to about 11:30am
greatly reduces the hiss with the 125hz filter in.  Now, using an 80m
vertical as a sensitive, but noisey RX ant, I can easily copy very faint CW
signals.

The INRAD IF amp mod has been installed and it does make receiving more
sensitive, but at the cost of quicker IF overload.  But with the 125mhz IF
filter in, there is now no overload or key clicks, even from very strong
adjacent local stations.  The frying code sound of strong sigs up the band
with the NB on, is also eliminated, so I can now take advantage of power
line buzz reduction.  Strong static crashes can still come through, causing
some ringing.  On SSB, none of this works, so its back to EDSP & wide
filters in that mode, applying some front-end attenuation when local sigs
hit 40+db over S-9.

Everything I cook up seems to be unorthodox, and searching for the
proverbial "free lunch", but something had to give on this RX noise problem,
and I was lucky to find this.  Now if I can just get these experimental,
floating shield phase lines to quit receiving noise on the flag, I will be
in business.  Steelwool and Moxon linear RF chokes on the floating coax
shield looks promising........mebbe even permanent magnet rings........

Hope someone with an MP, living in infernal noise on a subdivision lot can
find better loband reception from this info.  In the meantime, we all must
do what we can with what we have, until a REAL topband transceiver hits the
shelves.......

73/MagicBand DX, om Doug / NX4D