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Re: MicroWave: 1296 Transverter design advice

> Date:          Sat, 27 Feb 1999 03:39:31 +0000
> To:            "K.R.Burtchaell" <kburt@jps.net>
> From:          Steve Harrison <ko0u@os.com>
> Subject:       Re: MicroWave: 1296 Transverter design advice
> Cc:            Dave Metz <davemetz@muscanet.com>, microwave@wa1mba.org

> Quite doable. For a ham, the primary real-estate consumer is, as always,
> the RF filters; specifically, before the mixer to reduce image sensitivity.
> 900 and 2400 MHz consumer goods have helical filters available from Toko
> and others. I've not had a chance to look at those myself so don't know if
> there's any possibility of modification or if new designs must be developed
> for the amateur bands.
> And only some 2400 MHz systems are truly linear; as far as I've seen, power
> amplifiers for the 900 MHz stuff are always Class C or higher (usually
> higher, such as class D and E). 


A big help in the transverter quest would be a cost effective wide band
amp to go from the 10 - 50 mW level to the 1 watt level.  From there a 
hybrid amp can take us to 15-18 watts.

> Another consideration for the amateur is the fact that the lead spacing of
> these surface-mount devices dictates that interconnecting PC traces be much
> narrower than most of us are used to, which in turn implies using a higher
> dielectric constant and thinner substrate than most of us have used in our
> own labs


Another desire of mine and perhaps not a practical one is to keep the
requirements for the PC board within the ability of the average homebrewer
to reproduce.  This is why I have stayed away from the "no tune" designs,
I'm not sure I could reproduce them.
> Actually, Ken, your definition of area being no more than that of a playing
> card fits my own 220 and 1296 XVTRs pretty well (they're both maybe a
> half-inch longer but about as wide); the problem is that the VOLUME of each
> transverter is considerably more, since each is around an inch thick
> (except the power amplifiers beyond 200 mW). Since I didn't pay any
> attention to conserving power, each "brick" also gets fairly warm while
> simply idling in RX mode! And yes, more than half of that volume is taken
> by several coupled-line and helical filters.
Have you published anything on these designs.  The size alone is 
impressive!  Your transverter is smaller then one of the helical resonators
in my 220 rig!
> Zack Lau has built some very small and "cute" transverter modules, but I
> haven't seen any of his latest efforts over the past several years (nor
> heard of him since his stroke last fall, for that matter; any updates,
> anybody?).

I spoke to him by accident this week when I called the ARRL.  Maybe if
he reads this, he'll give us an update.
> 73, Steve Ko0U/1
>--73-- David WA0AUQ 

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