[Amps] 4xc250b Valve Bases - Screen ring capacity - HF v VHF

[Steve Thompson]

Ken G3WCS wrote:
> Gary Smith wrote:
> 
>>Hi Ken and all.
>>I suggest you go to www.eimac.com <http://www.eimac.com> and look for 
>>the solution there.  
> 
> 
> Thanks Gary,
> 
> Took a look and also at the pages to which the site links. Opened up 
> quite a few PDF's for the various valve bases for the 250b. Looks like 
> the SK600/610 has a 2700pf decoupling ring whilst the SK620 has an 
> 1100pf ring.
> 
> I'm guessing therefore that the 600/610 is for HF use and the 620/620A 
> id for VHF/UHF use.
As far as I'm aware, the SK620 is the only base that works reliably at 
UHF with the '250. The SK620, and every other base I've ever met, works 
ok at VHF and below.

Can you post a picture of the base you have somewhere, maybe we can 
identify it.

Steve