[Heathkit] SB-300 and SB-301 Filters

[Eddy Swynar]

On 2012-03-11, at 7:19 PM, L L bahr wrote:

> Awhile back I asked what the differences were between the SB-300 and SB-301 receivers.  Among other things,  I was told the AM filter was widened on the AM filter and the CW filter was narrowed.
> 
> That said, are the filters interchangeable between the two receivers?  I know the IF frequency are the same, but are the footprints the same so the pins of the filters will mate up with the sockets of either receiver?  (Can you plug in a SB-300 filter into a SB-301 and visa versa)?
> 

Hi Lee,

The electrical characteristics of the filters between both receivers ARE IDENTICAL, but physically the filters for the '301 are SMALLER than those used in the '300...

They are NOT directly interchangeable that way, but that certainly doesn't mean that one can't retrofit one to fit the other!

As far as I know, the bandwidths are the same---i.e. 400-Hz for both CW filters, ditto for the AM filter bandwidths---however, if you want a WIDER AM filter, you'll have to acquire the one used in the SB-310, the SWL version of the '30.

They ARE "homebrewable"---in fact, some years ago I cloned the SB-310 AM filter for my '301, utilizing an old SSB filter carcass as its foundation. All you need is that "base", & some select new crystals...

~73~ de Eddy VE3CUI - VE3XZ