Many forget the sweep tubes were used as the horizontal output tubes in TV sets. They ran hours at max conditions. Unfortunately when they are used in ham sets, the ability to exceed the grid and plate currents when tuning gave these fine devices a bad wrap. If you follow the book and tune as asked, they will last a long time. As to your question, the bias for the tubes are manufacturer sensitive. As Drake used mostly Sylvania tubes, they suggest to reuse the same. David Assaf, III W5XU
On Thu, Mar 21, 2013 at 1:40 PM, Charles Ring <[email protected]> wrote: > I've always questioned Drake's decision to use the 6HF5 in that > transmitter. Sweep tubes made some sense for SSB at the time, but a CW > transmitter meant for beginners? A 6146 would have been so much more > forgiving and reliable. > > 73 de W3NU > > > > On 3/21/2013 1341, Curt Gidding wrote: > > The manual suggests that the final 6HF5 be replaced with the same > manufacturer tube as > is in the xmtr. How critical is this? Is there one manufacturer that is > better? Tnx for your > reply. > > Curt Gidding KC9UNL > > > > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist > >
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