[amsat-bb] Any experience with low-cost 433MHz transverter from transverters-store?

[John Toscano]

The transverter itself can cover the satellite portion of the band. The
specs say it covers 432 - 442 MHz. The issue is that your IF radio, the
Icom IC-706MkII is what I believe you meant to say, can tune high enough on
the 10M band and above for RECEPTION at the appropriate frequencies, but
will not transmit above 30 MHz and therefore, through this transverter,
will not transmit above 435.0000 MHz. I know this from experience with my
222 MHz transverter. Fortunately, on that band, 28-30 MHz -> 222-224 MHz,
and the portion of the band above that (224-225 MHz) is mostly FM repeater
OUTPUTS, which the radio will happily receive through my transverter.

What you would need to do is defeat the 10M band transmit limits on your
IC-706MkII. You can probably find mods to allow that.

Your other issue, which I also had to overcome with my 222 transverter, is
that the transverter needs (accepts) only a very low RF power signal on
transmit (1-100 milliwatts) and your IC-706MkII is happy to transmit 1000
times as much power, up to 100 watts. So you will need to carefully
interface the radio to the transverter to insure that the transmit power is
nice and low. In my case, my transverter interface includes a source of
negative voltage to feed into the ALC input of the radio, which can drop
the power low enough. Interesting (=undesirable)  things happen if this ALC
circuit fails, or more likely, gets accidentally disconnected. I was
fortunate, when I transmitted 100 watts into my transverter by accident, I
only fried a 50 ohm resistor in the input circuit, and after replacing it,
all was good again, The same may or may not hold with this transverter.

Good luck in your search for a solution.

John Toscano, W0JT/5

On Sun, Jan 31, 2016 at 12:46 PM, Eric Wolak <ag6ie at wolak.net> wrote:

> Hi folks,
>
> I'm trying to get on the air with the linear transponder satellites, and
> it looks like I need 70cm SSB capability to really get on the air. My
> Icom IC-796MkII can do SSB on 2m, but not 70cm, so I'm trying to find an
> affordable way to get 70cm SSB transmit.
>
> Does anybody have experience with these $100 transverter boards from
> Ukraine? It looks like they're tuned for the weak-signal/SSB end of the
> band and might require a bit of work to get up to 435MHz for satellites.
> Is 3-4W enough to be heard?
>
> http://www.ebay.com/itm/221871269275
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