[Elecraft] WTB Trimble ThunderBolt for K3EXREF / QS1R

[Edward R Cole]

A caveat regarding the use of simple "wall wart" 12v PS for supplying a OCXO.

I am using a Morion OCXO as 10-MHz reference for my K3EXREF and for 
my synthesized A32 PLL in my DEMI 1296 transverter.  I got reports of 
120-Hz sidebands on my signal (-10dBc) turned out to be due to 
excessive AC ripple riding on the 12v coming from my wall wart supply 
that I was using to power the OCXO.

Using a scope I measured half a volt ripple on the 12v dc 
output.  Substituting a clean 12v PS eliminated the sidebands.
So be careful if you use a wall wart (many rectify with no dc filtering).

I had a 17AH battery being charged by the wall wart which I assumed 
would present some filtering if 12v ran thru the battery to the 
OCXO.  I could have added a large value electrolytic cap to do the 
filtering but I changed dc source to a well filtered Astron PS.


73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
Dubus Mag business:
     dubususa at gmail.com