[R-390] More Filter Options

[Bob Camp]

Hi

With the exception of watch crystals, the whole industry of sub 1 MHz crystals is pretty much a thing of the past. Yes, there are a couple of people who will make you this or that. You better have deep pockets to get them interested in what ever you need done. Yes, one of them is a buddy, but that only goes just so far.

The main technology still in existence is ceramic. There it's not so much can or can't, it's weather anybody wants to make complicated ceramics anymore. It's a market size sort of thing. People just don't make analog filter based radios anymore …

Bob


On Feb 16, 2013, at 6:25 PM, Perry Sandeen <sandeenpa at yahoo.com> wrote:

> List,
> 
> It appears from Cuck Felton’s ad in ER that he has obtained crystal filters as well as new meters for the R -390A’s that he re-mans.  I don’t any details. 
> 
> On page 113 of Chapter 9 of the R2KR3 there is an article by Dallas Lankford on how to install a 6 KHz Collins low cost filter in the R-390A IF strip.  It includes the details for winding the matching torrid coils that are needed.
> 
> If the Collins filter is too much for your wallet $$$ of Nebraska has ceramic filters in the $16 range but one would still have to have matching torrid’s.  I don’t know if the values Dallas used for the Collins filter would apply. 
> 
> Shameless Plug:  Many questions asked on the reflector list have been answered in the Y2KR3 chapters 9 thru 13.  Roger’s tutorials can take ANYONE with the willingness, who has basic mechanical skills, a minimal amount of test equipment and patience through all the steps to have a first rate “A”.
> 
> There are a plethora of other articles for making your  “A” better than when it came new from the factory.  Best of all it’s a free download.
> 
> Regards,
> 
> Perrier
> 
> 
> 
> 
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