[DSP-10] DSP-10 to 70 cm

[Bob Larkin]

Hi Courtney,

A transverter for 432 would be a great project.  Be aware that low-side LO 
(288 MHz) for 432 to 144 is not a good combination, because 2x288-144 is 
also 432.  In a DBM this is rejected by the mixer balance to some degree, 
but it would still be problematic.  The good news is that high side LO (576 
MHz) does not have this problem. And, the DSP-10 software already allows 
for this and will make all the reversed side bands (LSB/USB, etc) 
transparent to the user.  This is set by the transverter parameters in the 
UHFA.CFG configuration file.

While you are at it, I vote for making the LO phase-locked to the 10 MHz 
reference!

Go for it!

73,
Bob Larkin W7PUA

At 04:49 PM 4/15/2006 -0700, you wrote:
>Yeah, this is one of the places that I found in previous searches, and I 
>had worked with Bill at Down East years ago in my AMSAT days (2400 - 144 
>Rx in particular).  The problem with all these places is that there's 
>nothing that goes to/from 70 cm to anyplace but 28 MHz.  And, secondarily, 
>they all use crystals for the L.O.  So you have to buy another crystal to 
>go beyond 2 MHz range and you don't phase lock to anything.
>
>Designing my own as a "learning experience" is beginning to sound like the 
>best way to go.  "How hard could it be?" he was heard to ask.
>Indeed, some thought those words might have been the last they'd heard 
>from him...."
>
>-n5bf/6
>
>
>Roger Hayward wrote:
>
>>The other place that might be a good way to stir up some ideas is by looking
>>at Down East Microwave (www.downeastmicrowave.com) .  Steve (the guy @ DEMI)
>>has a variety of transverters from 6m thru 10 GHz.  The projects go together
>>without too much trouble.
>>
>>FYI.
>>
>>-----Original Message-----
>>From: dsp-10-bounces at mailman.qth.net [mailto:dsp-10-bounces at mailman.qth.net]
>>On Behalf Of Courtney Duncan
>>Sent: Saturday, April 15, 2006 3:17 PM
>>To: Discussion of DSP-10 2-meter transceiver
>>Subject: [DSP-10] DSP-10 to 70 cm
>>
>>I would like to put my DSP-10 on 432 (435) MHz but a google search on 
>>transverters doesn't find much these days in terms of off the shelf 
>>converters or kits.  I suspect that since every rice box made today 
>>(seems like) has 2 meters and 440 (and even 1.2) that there isn't much 
>>market for such building blocks anymore.  For the applications I have in 
>>mind, this equipment would need to be phase locked to the same reference 
>>that runs my DSP-10, so that would probably be a mod to an existing 
>>product, if there is such a thing.
>>
>>So I'm wondering how to proceed.  Possibilities that come to mind:
>>
>>- Something from the past -- ebay?  People's junk boxes?
>>- A design from the past (or present!), like from QST or QEX, that I 
>>could scrounge, etch, build, and modify.
>>- Design my own?  I feel nearly ready for this, but would need some -- 
>>advice on parts, layout, tricks, even packaging.
>>- A contemporary product that my searches have missed (because I don't 
>>know what to call it or it's not on the web or whatever).
>>
>>I have a second DSP-10 that I will be building sometime in the next year 
>>or three and have even considered re-engineering it to 70 cm.  Like, the 
>>126 MHz PLL becomes 412 somehow, and every relevant filter and amplifier 
>>in the upstream chain has to be redesigned, replaced or at least 
>>retuned.  This is over my head right now and if it wasn't then I'd 
>>probably just know why it isn't a good idea.  Anyway, I don't want to do 
>>that because I want the two DSP-10s to be roughly interchangeable.  (And 
>>I'd be back here asking for a 70 to 2 converter.)
>>
>>Any thoughts, advice, or offers from anyone here would be appreciated.
>>
>>Courtney, n5bf/6 DM04vf
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>>
>>
>>
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