[ARC5] 75 Mtr to LF Converter - Ideas?

[David Stinson]

Thanks for the help, guys.
Don't know what I was thinking to call the input a "hi-pass;"
it's obviously a low-pass.  My only excuses are general
doo-fuss-ness and that my doctor took me off caffine.
I was raised in Louisiana,
and our hearts don't usually even beat before at least
three cups of coffee ;-).  In fact, I think I'm going to
"flip-off the Devil" this morning and have a cup of
steaming-hot Hi-Test.  One won't hurt... (crossing fingers).
TNX Dave S.


Mike Feher wrote:

> Dave -
> 
> I would suggest changing the simple input lowpass filter to an elliptic
> bandpass filter with sufficient attenuation in the image band. So, depending
> on which 200 KHz segment of 75 meters you chose, you can design the BPF to
> be centered on it remembering that the image will be 2 times the IF
> frequency away, which in this case will vary from 400 KHz to 800 KHz.
> Elliptics have a very sharp transition band and a good deal of attenuation
> in the stop band, depending on the number of section you choose. 73 - Mike
> 
>  
> Mike B. Feher, N4FS
> 89 Arnold Blvd.
> Howell, NJ, 07731
> 732-886-5960
>  
>  
> 
> -----Original Message-----
> From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On
> Behalf Of David Stinson
> Sent: Tuesday, January 11, 2005 1:07 AM
> To: ARC5 at mailman.qth.net; Boatanchors
> Subject: [ARC5] 75 Mtr to LF Converter - Ideas?
> 
> I've uploaded a diagram, formated for printing, of a simple
> converter I built to receive 75 meters on a Beacon Band
> (200-400 KC) receiver.
> It is at:
> 
> http://home.mindspring.com/~arc5@ix.netcom.com/convertr.jpg
> 
> It works, but images are a problem with that low IF, of course.
> I didn't hope to eliminate them with this simple design,
> only minimize them.  But they are more annoying than I expected.
> The net is full of people smarter than me.
> May I ask for your suggestions?
> Thanks.
> 
> 
> 
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