Hi, Everybody,

Would anybody know offhand which rigs from maybe the 1960s through early
1980s era had an IF of 10.9 MHz? I have a number of 10.9 MHz crystal filters
built by Network Sciences (C-F Networks) that I bought some time ago that
were supposedly taken out of a ham rig and just out of curiosity wanted to
know which one.

Thanks very much.

Regards,

Al W6LX

On Tue, 6 Feb 2007 22:57:25 -0800, "Al Lorona"
wrote:

Hi, Everybody,

Would anybody know offhand which rigs from maybe the 1960s through early
1980s era had an IF of 10.9 MHz? I have a number of 10.9 MHz crystal filters
built by Network Sciences (C-F Networks) that I bought some time ago that
were supposedly taken out of a ham rig and just out of curiosity wanted to
know which one.

Thanks very much.

Regards,

Al W6LX

ISTR that some older Bearcat scanners used 10.9Mhz. I don't know any
other rigs using it though.

On Feb 7, 1:57 am, "Al Lorona" wrote:
Hi, Everybody,

Would anybody know offhand which rigs from maybe the 1960s through early
1980s era had an IF of 10.9 MHz? I have a number of 10.9 MHz crystal filters
built by Network Sciences (C-F Networks) that I bought some time ago that
were supposedly taken out of a ham rig and just out of curiosity wanted to
know which one.

I have seen 10.9 MHz crystal filters used in RC receivers from the
60's and 70's. Don't know if it was a technical reason or just "vendor
lock-in" for the channelized crystals (that's what the modelers told
me it was).

Tim.

Thank you for your responses. These filters were definitely from the very
early 70s or maybe mid- or late 70s. The guy who sold them to me at the swap
meet mentioned that they may have come out of a Cubic or Astro rig of that
era, but he wasn't sure and I just wondered if there was anybody here who
might be sure of that.

Thanks again, you guys.

Al W6LX

"Al Lorona" ) writes:
Thank you for your responses. These filters were definitely from the very
early 70s or maybe mid- or late 70s. The guy who sold them to me at the swap
meet mentioned that they may have come out of a Cubic or Astro rig of that
era, but he wasn't sure and I just wondered if there was anybody here who
might be sure of that.

Thanks again, you guys.

Al W6LX

The name of the filter manufacturer that you mentioned, that did sound
like the company that made the Swan filters (Cubic and Astro came later
in the seventies, but my hazy memory connects them all together so I
think there is a connection). I remember ads (and a quick check
didn't find one) of them touting a really good filter made by
that company. But I'm pretty certain it was in the 5MHz range.

What does come to mind, maybe incorrectly, was that the Swan 250, the
six metre SSB rig, had a 10.7MHz IF, but I can't be bothered to check that.
I can't even remember why I would think that. But I can't see them going
to 10.9MHz.

I'm with the others, 10.9MHz is most likely a scanner (and I too would
say Regency). And if it's not that, then it's some non-amateur piece
of equipment. Not everything has to be for ham radio rigs, and I have
my share of oddball crystal filters that came from somewhere but
couldn't have been ham rigs.

Load the inputs and outputs down to some extent, and then use a sweep
generator to get a general idea of their bandwidth. If you're looking
for SSB-width filters, then they aren't useful if they were for FM
receivers.

Post the information printed on the filters, and maybe someone just
happens to know.

Michael VE2BVW

Post the information printed on the filters, and maybe someone just
happens to know.

Michael VE2BVW


Hi, Michael and others,

Ron W6ZI was kind enough to solve this mystery and respond with the
following:

"The 10.9MHz C-F Networks filters were used to replace the standard filter
in
the Swan 250. The 250 had a 10.7MHz I.F. so a bit of retuning was required.
The stock 250 filter was a 4 pole, 3KHz (more or less) B.W. while the C-F

was an 2.8KHz, 8 pole which provided a very noticable improvement. Hope this

helps."



Thanks, Ron.

Regards,

Al W6LX

"Michael Black" wrote in message
...
I remember ads (and a quick check
didn't find one) of them touting a really good filter made by
that company. But I'm pretty certain it was in the 5MHz range

Michael VE2BVW


Micheal

You have a good memory. MHZ Electronics was dumping
5.9XX USB, LSB and CW filters in full page ads in Ham
Radio Magazine back in the late 70s or so if my memory
holds. I remember buying several of each for future projects
that never have materialized.

Pete