Re: mono band 2 meters rig based on the micro BITx circuit #ubitx #2meters

ajparent1/KB1GMX <kb1gmx@...>
 

On Fri, Apr 27, 2018 at 10:18 pm, Ashhar Farhan wrote:
Should be mangle an ADE-1 to get at its transformers? Allison, can you help?

Mixers specifically for UHF are easy to do.  1n5711 is not ideal.  We are now in the
range of bat5x or bat6x SMT series.  Also the mixer does not have to be DBM it can be
rat race or any number of other possible flavors. 

However you need a good solid amount of low noise (under a DB) RF gain before it
and a stable LO or its not going to fun or hear much.  Images hit you  for 3db off the top.
Modding a commercial mixer is way too costly and more effort when a model for the
range is available for the same cost.

Going to a high IF (up to 45mhz or so) means narrow filters at UHF and doing that
without incurring high losses is not simple to build or tune.   Gain is cheap if the cost of
MMICs are not off putting but most MMICS are fairly noisy for receiving.  Board materials
like G10 and FR4 are noticeably lossy and the fancy low loss stuff cost dearly.

I'd call 6M the breakpoint for simple design, 2m transitional for understanding VHF
and up design and 432 the starting point for UHF design.  The next bend is around
3000mhz.  I happen to like the world above 3000mhz but I'm likely nuts.

Allison




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