[1000mp] 70 MHz IF tap

[Tod -ID]

This is a good point Mort. I expect that one will need to use something like
a FET follower to transform the signal from the voltage at 70 MHz and high
impedance to essentially the same voltage a lower output impedance, say 50
ohms so one can use small diameter coax to get it out of the FT1000X. 

I have something like that in the preamp I use for my active whip vertical
[102 inches high]. It has a pair of FET's in follower configuration. The
input impedance is greater than 2500 ohms and the output is 50 ohms.


Thanks for the suggestion.

Tod, K0TO

> -----Original Message-----
> From: marditti at dslextreme.com [mailto:marditti at dslextreme.com] 
> Sent: Monday, November 26, 2007 12:57 PM
> To: All about Yaesu 1000mp
> Cc: 'All about Yaesu 1000mp'
> Subject: Re: [1000mp] 70 MHz IF tap
> 
> Tod,
> 
> There is another item to consider.
> At 70 MHz, the loading by any cable at the tap point may be an issue. 
> Therefore, it is necessary to look at some detail at the 
> circuit.  I would think that any tap must include a buffer 
> with high impedance, low capacity input.  In addition the 
> buffer should have adequate bandwidth for the task, but not 
> be to wide band.
> 
> Mort, KB6BSN
> 
> 
> 
> Tod -ID
> > I am looking into tapping the 70 MHz IF signal prior to the 
> entry into 
> > the roofing filter. The objective is to get a signal which 
> can then be 
> > down converted to an IF frequency that can be received by 
> one of the 
> > single board Software Defined Radios. There is now available 'free' 
> > software that will generate a "Bandscope" display on a 
> computer screen 
> > using the output of such single board radios.
> >
> > If someone has already done this I would be interested in their 
> > experiences before I make my effort to do it. If anyone has 
> ideas on 
> > how to do it; warnings about potential problems (a) changing the 
> > characteristics of the original FT1000X or (b) challenges in down 
> > converting and/or selecting an IF frequency to use for the 
> SDR or any 
> > other advice I would appreciate their comment.
> >
> > Tod, K0TO
> >
> >
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