John - G3JAG wrote:
> I just downloaded a couple of the Synergy spec sheets, out of
> curiosity. They give enough info for me to stick my neck out and
> pontificate, although I do not have an Omni-VI. My Omni-V appears to
> use exactly the same mixer -- unless someone out there knows better.
>
> There should be no problem - the Synergy CMP 212 is probably a safe bet.
> It appears to have all the right characteristics. I cannot believe that
> they made a version of it with a special pin-out, just for TT - these
> packaged mixers all have the same pin-out almost regardless of
> manufacturer. Ham Radio even published a generic PC board layout
> based on this common pin-out.
>
> Unless the TT mixer really is unique, the Mini Circuits RAY-3 is a very
> safe bet. I found one for a few bucks at Dayton (its a $50+ piece here
> in UK) and I'd have no hesitation in dropping it into my Omni-V if I
> thought the mixer had gone out. The SRA1-H may be another option. The
> key figures to look for are the local oscillator level (17 dBM or
> higher) and the frequency range, which needs to go low enough, like
> down to 0.025MHz (most go high enough). The regular SBL-1 type of
> device simply does not have the local oscillator signal handling
> capability.
>
John et al,
I have two MCI SRA-3H and decided to try one in my OMNI VI (upg3). It
works good. I cannot tell the difference from the original Synergy mixer.
I am terminating the mixer with a Crystalonics power fet CP 643 (which
provides 50 ohms resistive at 30ma). Crystalonics is back in business,
they have a web site, and they sell in small quantities (expensive though).
I am not sure if the Omni V has Pass Band Tuning. However the 1st mixer on
this board is a discreet diode/xfmr DBM. I removed these parts and mounted
a MCI LRMS-1 (low priced surface mount plastic pkg DBM/LO +7) on the
underside of the pc bd . The receiver has less noise and maybe better IMD.
It is difficult to quantify without serious lab tests.
73 Bill N4WC
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