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-   -   Wearite BFO coil? (https://www.vintage-radio.net/forum/showthread.php?t=159827)

G3VKM_Roger 16th Sep 2019 9:37 pm

Wearite BFO coil?
 
Hi All,

I have a plug-in BFO unit, which is U/S, fitted in a Coastal Radio 91/MX marine receiver. The 91/MX IF is 470kHz and the single coil was made by Wearite, but unfortunately the type markings are too faded to read. I suspect the coil is O/C but need to lift some of the connections to do a proper continuity test.

However I have not been able to find any info online for a Wearite coil for a BFO application, so I was wondering if anyone had a catalogue or data sheet with more info, probably from the late 40s/early 50s era?

Thanks,

Roger

David G4EBT 17th Sep 2019 8:07 am

Re: Wearite BFO coil?
 
Don’t know if this helps Roger:

http://vintageradio.me.uk/info/wearite.htm

Good luck in your quest.

G3VKM_Roger 17th Sep 2019 5:51 pm

Re: Wearite BFO coil?
 
Thanks David, I can't see a BFO coil as such on that page but it helps to know what the various Wearite coils were used for.

73

Roger

ms660 17th Sep 2019 5:59 pm

Re: Wearite BFO coil?
 
You won't see a picture of it on the page or shown in the tables but it's described in the text, basically a 1000uH inductor tapped for Hartley osc operation, for an IF of 465kHz a capacitor of 118pF will give a 1kHz beat note.

Lawrence.

G3VKM_Roger 18th Sep 2019 6:42 am

Re: Wearite BFO coil?
 
You're absolutely right, Lawrence! I had looked at the drawings of the coils and the table. With that info I can probably wind a replacement coil if the original turns out to be O/C.

Many thanks,

Roger

G3VKM_Roger 19th Sep 2019 11:46 am

Re: Wearite BFO coil?
 
OK, got a little further with the coil problem. Removing the Wearite coil from the chassis reveals the part number is a PO7, an oscillator coil with two windings. One winding appears O/C. No sign of a PO7 on ebay or other sites so does anyone have one in their collection they will sell?

Cheers

Roger

G3VKM_Roger 25th Sep 2019 1:47 pm

Re: Wearite BFO coil?
 
Quote:

Originally Posted by ms660 (Post 1177043)
You won't see a picture of it on the page or shown in the tables but it's described in the text, basically a 1000uH inductor tapped for Hartley osc operation, for an IF of 465kHz a capacitor of 118pF will give a 1kHz beat note.

Lawrence.

A forum member has very kindly sent me a BFO coil, which I should be able to use in place of the PO7 type, although with some cct mods. If anyone has a PO7 kicking around I’m still interested in obtaining one.

Thanks

Roger


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