|[AMRadio] Best AM BoatanchorReceiver or AM RiceboxReceiver Discussion|
jcandela at prodigy.net
Sun Oct 1 12:15:57 EDT 2006
Yesterday morning on 75 meters we had at least 3 AM QSO's going on
simultaniously. It was glorious! I heard QSO's on 3880, 85, and 90. At the
same time there were SSB groups on 3878, and 3894.
At my QTH (central Texas) with my equipment, my SP-600 was useless. Yes I
could use the 3Kc IF bandpass position, and tune off center to favor one
sideband or another. As soon as the audio midrange would brighten up I'd
hear QRM from an adjacent channel. Switching in the 8kc position resulted in
a maddening array of signals besides the one I was wanting to hear.
Then I switched to my Icom R-75 with 3 mechanical filters that are about
2.4, 3.5 and 6 khz in bandwidth. I could hear all 3 QSO's Q5 in AM with the
3.5 Khz filter, but it was no fun because the upper mids, and all highs were
gone. Then tune off 1 Khz, and much better or turn on the synchronous
detector, offset the passband tuning 2.4 khz (or 3.5), select the 2.4 filter
(or 3.5), and golly Gee! Nice sounding AM on all 3 QSO's so long as you pick
the better sideband.
As the morning went on the QRM went away, and all we had was the traders net
on 3890. Now the SP-600 ruled until the signals started dropping from
daytime propagation kicking in. Now I was experiencing QSB, selective
sideband fading, and occasional impulse line noise. Switch back to the R-75,
turn on the noise blanker, and synchronous detector. Back to Q5 again!!
This is not a tube versus solid state issue. Chuck Wa0zhh has a all tube HB
receiver that has most of the modern features, and his receiver can probably
blow the doors off my R-75. Chuck likes old style octal tubes too like the
6L7 in his noise blanker circuit.
So how would a R-390 have done yesterday, or a NC-183D, Bretts HB tube
receiver, or one of Darrel's HB tube receivers?? Just curious.
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