[Hallicrafters] Nuvista-plug

[lrlayton at cox.net]

The Nuvista-plug  has been tried in a couple of my radios, just a seat of the pants evaluation but here are the results.

First I tried it in my SX-42 as a sub for the 6AG5 in the first RF stage with poor results... gain was very low and no apparent improvement in noise figure.  Really not usable on any of the bands that use the first RF stage. I did not try to peak up the alignment.

Next, I installed the Nuvista-plug in a National NC-183D that normally uses a 6BA6 in the first RF stage. The results were excellent... lower noise on the higher bands and gain approximately the same. Again, no alignment was done other than  peaking the antenna tune control. There isn't much to hear lately on 6 or 10 meters, but on 27 mHz, it was possible to copy weak local  signals  better than before.  No overload from strong signals was noticed or other ill effects on any of the lower bands.

Les


For those who missed the original discussion a couple of weeks ago here is the link provided by Carl to the info on the nuvista-plug (a  cascode circuit using two 6DS4 nuvistors designed as a low noise plug-in replacement for the first RF stage in the SP-600).

http://www.mines.uidaho.edu/~glowbugs/SP600upgrd.pdf