[Hammarlund] IF bandwidths?

[Eugene Hertz]

I found a very interesting circuit that I will persue.  It is figure 25 on page 10 in the MC1496 data sheet which can be found here: http://www.onsemi.com/pub/Collateral/MC1496-D.PDF
 
I just have to figure out how to supress one sideband, and I think I might be onto something!

I've been trying to figure out some details, it seems like if I plan on a 100khz bandwidth centered on 455khz (+/- 50khz), I would have a choice of LO's depending on if I want to use the LSB or USB image. Please correct me here because I am first just learning about this stuff. The LO options would be 21.855 and use the LSB or 20.945 and use the USB. But what I think I figured out that my only option is 21.855 and using lsb, otherwise the unwanted image will show up in the bandpass. Something like that. 

Anyway, getting back to hammarlunds. I also realized that these radios have two conversions, does anyone know if the IF bandwidth is wider after 3.955 or 455 when two conversion stages are used?

Eugene
 


>-----Original Message-----
>From: peter markavage [mailto:manualman at juno.com]
>Sent: Wednesday, October 12, 2005 04:09 PM
>To: hammarlund at mailman.qth.net
>Subject: Re: [Hammarlund] IF bandwidths?
>
>Why not just build a simple 1 tube (or solid-state) mixer. 21.400 - (1st 
>IF Frequency) = Mixer Frequency 
>Pete, wa2cwa 
> 
>On Wed, 12 Oct 2005 20:53:51 +0000 "Eugene Hertz" <ehertz at tcaf.org> 
>writes: 
>> Hello all, 
>> 
>> I am undertaking a project (probably foolishly) to adapt a 21.4mhz 
>> panadapter for use with various hammarlunds, specifically sp600, 
>> hq140x, hq129x. The idea is to use a balanced modulator, and no, I 
>> havent figured it all out yet (and it may not even be possible). 
>> 
>> In trying to figure it all out, I was wondering if anyone has ever 
>> made any IF bandwidth measurements of these receivers at their 
>> widest points in the circuits, before filters. 
>> 
>> Thanks 
>> Eugene 
>> 
>> 
>> 
>> 
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