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

Sun Feb 7 17:37:58 UTC 2016

Ahhh, right. I still only have one SSB modulator/demodulator, no matter
how I slice it. Back to the RTLSDR stick!

On Tue, Feb 2, 2016, at 12:19 PM, John Toscano wrote:
> No, if you are using an Icom IC-706MkII as your IF radio, it cannot
> operate in full duplex mode. It CAN do split-band Tx/Rx, where you
> receive with the built-in 2M section and transmit on 10 meters into
> the transverter to get 70 cm output. Or you can receive on 10 meters
> which becomes 70cm through the transverter, and transmit on the built-
> in 2M section of the radio. But you can't hear while transmitting. You
> would need a second radio or a radio that is designed for full-duplex
> operation.
>
> If you could find a deal on another IC-706MkII and add the 70cm
> transverter to it, you'd then have a full-duplex station. A less
> expensive choice might be an IC-703, which lacks the 2M band, but you
> only need 10M to run the transverter anyway, so it would still make a
> nice matching pair of radios that would work well for satellites. Or
> if you could find an IC-706MkIIg then you'd have a nicely matching
> pair that includes 70cm on the new radio and you'd use 2M on the older
> radio. Kind of pricey, but it's just a couple of suggestions that
> could be made to work.
>
> Another popular choice is a Yaesu FT-817. But then you would not
> need a transverter since it has both 2M and 70cm bands already. You
> just might need a PA to output more than 5 watts on mode UV, but no
> extra PA needed for mode VU since the transmitter is the IC-706MkII
> in that mode.
>
> Choces, choices, choices... And we didn't even get into full-duplex
> radios like a Yaesu FT-847. (I love mine!)
>
> Happy shopping. John, W0JT/5
>
> On Mon, Feb 1, 2016 at 11:06 PM, Eric Wolak <ag6ie at wolak.net> wrote:
>> Thanks, guys! It looks like the transverter kit includes an
>> attenuator
>>
board to interface with a radio, so I'm set on that. These transponders
>>
work both ways, right, so if I can TX on 2m and RX on 70cm (through the
>>
transverter), then I can hear my own transmissions full-duplex, and I
>>
can make contact with someone TX'ing on 70cm?
>>
>>
Are there any attributes that might be lacking with such a low-cost
>>
option, e.g. frequency stability or harmonics?
>>
>>
On Sun, Jan 31, 2016, at 03:12 PM, John Toscano wrote:
>>
> 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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