[R-390] question

[mikea]

On Thu, Jun 28, 2007 at 09:58:16AM -0400, John Lawson wrote:
> 
> 
> On Thu, 28 Jun 2007, Barry wrote:
> 
> >>a scope, placed around the vicinity of the 17Mc osc.
> >>Tim.
> >>
> 
> >
> >Scopes are for wimps.  ;)
> >
> 
>   Um, no. 'Tube Testers' are for wimps.
> 
>   Scopes are for KL3WL3SS N00BZ
> 
> 
>   I can't wait to see what kind of loser I am for having/using a spectrum 
> analyzer...

<puts fingers in ears, shouts>
We Can't Hear You! LA LA LA LALALALALALALALALAaaaaaaaaaaaaa

My speccy only goes to 30 MHz, being one of those lovely RFSpace Inc. 
SDR-IQ radios-on-a-card, but it and a signal generator make a *great*
demonstrator of what modulation actually looks like in the frequency
domain, and adding a 'scope to look at the modulated RF lets the 
students see the signal in the RF domain at the same time. It's very
effective. 

I found a little 4mm x 4mm chip that'll make a great downconverter for
it, covering 1 KHz to 3 GHz; it's the Linear Technology LT5512. Looks
like there's an evaluation board in my future, as I'm not up to all 
that teensy soldering. All I'll have to supply is LO and filtering, 
which probably means an AD9854 or similar, a tracking preselector, 
and a PIC or similar, to control the AD9854.

R-390 and GlowBug connections:
1)	I sometimes use an R-390 or R-390A to detect the (AM, SSB) signal,
	just to show people that those old "toob" things co useful work.
2)	I can imagine the rackspace required to do all that in glowbug 
	hardware, but I wouldn't want it lit up in my shack in summer. 

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin