[Hammarlund] Old Hammarlunds

[Ross Stenberg]

And a modern day rig may drift .0004 KHz, but not nearly as cool....or 
should I say warm.


On 4/12/2011 10:23 AM, djed1 at aol.com wrote:
> I have both a BC-779 and a SP-400, so I'll offer my experiences.  It's been a couple of years, so some issues are a bit hazy.  I restored the BC-779 and was surprised at how bad it drifted- 75 KHz from a cold start at 20 MHz.  I finally found some TC caps, and put in two 10 pf in series.  This reduced the drift to about 50 KHz.  This is with the dust cover on- it may be significantly better in open air, but nowhere close to anecdotal numbers.
> As for the SP-400, I got one that had TC caps installed, but I have no idea if they are original.  The radio had been worked on, so they may have been added.  I did get the original manual, and the schematic doesn't show any compensation.  I do remember that the SP-400 drift was much better than the BC-779 when on the bench- maybe 15 KHz.  But after I put it in the cabinet it wasn't much better than the BC-779.
> Just to show how the technology changed, my SP-600 drifted about 12 KHz from a cold start, and the R-390A drifted 0.4 KHz.
> Ed  W2EMN
>