[Hallicrafters] [From Your Hallicrafters Reflector] ? Unusual filter in SR-400

[Jim Liles]

Good morning Walt, Wes, Carl I have a few questions.

Walt, I have not cracked the code for the five levels of the SR-400 Cyclone regarding the meaning of the serial numbers.  Sounds like you may have an answer so I can put that to bed.   

Wes, did the Swan series use the 1650Kc filter in any of their radios?  

Carl, do you know of any other radios using a 1650Kc filter other than Hallicrafters?  I’ve seen them occasionally but never associated with a radio MFG. 

A super day and thanks --- Kindest regards Jim K9AXN  

From: Walt Cates 
Sent: Monday, February 17, 2014 9:47 AM
To: hallicraftersradios at yahoogroups.com ; hallicrafters 
Subject: [From Your Hallicrafters Reflector] ? Unusual filter in SR-400

  

I am looking for information on vintage FILTECH xtal filters used in the SR-400. All of the Filtech filters in the 400’s have the Filtech logo and the Hallicrafters part # stamped on them.


I am in the process of upgrading a level 1 Cyclone 400 to a level 7 Cyclone II. This 400 is one of the first built, the 11th one to get a serial #. While checking my work I noticed that the input and output of the xtal filter read zero ohms to gnd. I checked my other three 400’s and they are all open to gnd.


I pulled the filter in question and found first that it was marked different than all the others. Along with the H part # and the Filtech logo there were the following markings.

          CRYSTAL FILTER

            FILTECH P/N 3121065

            C.F. 1650KC USB

Then I put the filter on the test fixture and it tests perfect.

Passband = 500 to 2800Hz ( 1650.500 to 1652.800KHz )

Insertion loss = 2.3db.

So the filter works perfectly but this filter is a much different animal from all I have seen before. The rig works and quite well but this is puzzling.

 


Best Regards, Walt Cates, WD0GOF
 
GOD put you here because there is something no one else can accomplish. 

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