[time-nuts] HP 8445B

Mike Feher mfeher at eozinc.com
Wed Jan 4 20:17:18 EST 2006


Rick -

I also had difficulty when I first attempted to put these to use. Similar to
your problem, it was insertion loss. The unit I wanted to use had an LED
display, and my other unit did not. I felt I had nothing to loose so I
changed the YIG filter from the "plain Jane" unit to the one with the
display, and low and behold it all worked fine. So, previously I was getting
about 14 dB of insertion loss and now it is back to the nominal 7 dB. BTW as
a consequence I do have a pair of those switches if you are convinced that
is your problem. Regards - Mike

 
Mike B. Feher
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
 
 

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Rick Karlquist
Sent: Wednesday, January 04, 2006 7:52 PM
To: Discussion of precise time and frequency measurement
Cc: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] HP 8445B

I have several of these, but the electromechanical relay contacts
have become dirty on all of them.  Is anyone familiar with
rejuvenating them?  Especially the idea of running a fairly high
power RF signal through them and hot switching them to burn off
the oxide.

Rick N6RK

Mike Feher wrote:
> These tunable YIG filters are going for practically nothing on ebay. While
> they only go to 18 GHz they make an excellent filter to follow testing of
> an
> LNA after the mixing process, for noise figure measurements, as an
> example.
> After all it is that noise that makes our time and frequency measurements
> questionable. I am surprised that they typically go for around $50 or
> less.
> They are externally tunable with a voltage source that is proportional to
> frequency. I bet a lot of you would be happy to own one. Regards - Mike
>
>
> Mike B. Feher, N4FS
> 89 Arnold Blvd.
> Howell, NJ, 07731
> 732-886-5960
>
>
>
>
>
>
> _______________________________________________
> time-nuts mailing list
> time-nuts at febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>
>



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