[Collins] Collins xtal filter help

[Dr. Gerald N. Johnson]

In normal Collins filter nomenclature, X308K0D100 means X for crystal 
filter, 308 for center frequency (or sometimes carrier frequency for a 
SSB filter), D for case and 100 for bandwidth though sometimes the 
trailing digits apply to a particular filter, and don't indicate 
bandwidth. Surplus Sales of Nebraska is willing to sell one for $125 but 
admits no information other than a picture which makes it look to be in 
the KWS-1 era.

I doubt 100 stands for 10 kHz bandwidth as it would with a mechanical 
filter because at 308 kHz 10 kHz is an impractically wide bandwidth for 
crystals, more likely its 100 Hz like the 200 Hz for a F455D D200 filter 
that plugs into a 75S-3B.

If the filter is to Collins normal specifications it will take about 100 
pf to resonate each end. Drive it with a high impedance signal sourcd 
and load it with high impedance (like 10K to 100K) and sweep it manually 
is usually better, fast sweeps WILL make it ring.

73, Jerry, K0CQ, Technical Adviser to the Collins Radio Association

On 7/14/2012 12:19 AM, L D Ritta wrote:
>
> Hello All
>
> I have a Collins xtal filter but I have no idea what frequency or bandwidth
> it is.
> These are the number etc
>   p/n 526-7103-00  type X308K-D100 cust p/n 293-0950-00
> Anyone have any ideas?
>
>
> 73's
>
>