[hpsdr] New kid on the block --> TransFox SDR

[Phil Harman]

> ***** High Performance Software Defined Radio Discussion List *****
>
> A 70MHz ~ 1400MHz version of Hermes would be great.
> Use I/Q demodulator/modulator mixers, change the ADC to a dual channel
> 40MHz unit (for a bit less than 20MHz bandwidth).
>
> Is the si570 good enough to use as a clock for a high performance V/U
> Hermes?
>

I tried using an Si570 as the second (1030MHz) local oscillator when
designing Cyclops.  Whilst the phase noise was acceptable the drift was
not. Hence I used conventional PLLs for the first and second local
oscillators.

Re the TransFox, my concern would be trying to maintain an acceptable
image rejection over such a wide frequency range. Whilst 70dB may be
acceptable on the HF bands, since images may be hidden under the general
band noise, at VHF and UHF this will not be the case.

Still, automatic image rejection techniques are improving all the time so
perhaps it's not a lost cause after all.


73 Phil...VK6APH


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