[amsat-bb] Re: Icom 9100

Edward R Cole kl7uw at acsalaska.net
Mon May 17 18:31:35 PDT 2010

At 02:38 PM 5/17/2010, tosca005 at umn.edu wrote:
>On May 16 2010, Sebastian wrote:
> > Perhaps others such as DEMI, will see this as an opportunity and come up
> > with alternatives?
>Well, keep in mind that DEMI's strength is in transverters, and what is
>hard to obtain for satellite operation from most common-place existing
>equipment is a full-duplex transceiver. I don't think that DEMI is likely
>to start building transceivers, but if you had a true full-duplex
>transceiver, they would have transverters available to upgrade the radio to
>the satellite bands needed.

Completely doable with current xvtrs.  Tell them what frequencies you want.

>Here's a thought: buy two SoftRocks for a lot less than the price of the
>Flex 5000 -- one would be the v6.3Rx/Tx and the other could be the V9 Rx
>only. This would net you two independent receivers and one transmitter, and
>with clever wiring, selection of VHF & up transverters, and maybe a little
>bit of software development, you could turn that into a software-defined
>radio that would be capable of full-duplex cross-band operation. (The V9 Rx
>would be the primary receiver, the receiver in the V6.3Rx/Tx would be
>"spare" or "extra" or even ignored.) You'd need to configure the
>transverters with "split IF"

Huh? Why?  Put a xvtr for the uplink band on the Tx and another xvtr 
for the downlink for the Rx.

>, and use two coaxial relays to route the 28
>MHz SoftRock IF Rx and Tx separately to the correct receive and transmit

I thought you had two separate Softrocks, so why the relays?

>  A bit of innovation/homebrewing would be needed for
>convenient band-switching, since you would need to switch two different
>transverters into the correct "position" depending on the mode: V/U vs. U/V
>vs. V/S vs. U/S vs. L/S vs. L/U vs. whatever other modes you wanted to
>support. But 4 transverters (145, 435, 1269, and 2400 MHz) would give you
>lots of satellite modes.

four xvtrs would give you every conceivable combination of up and 
down link: V/U, U/V, V/L*, L/V, V/S, S/V, U/L*, L/U, U/S, S/U, L/S, S/L*
* These modes are not allowed for Amateur Radio space-coms.

If each xvtr was configured for separate Rx and Tx antenna and IF 
connections the configuration tree would be simpler.  I count nine 
configurations (excluding HF bands).
If eighteen coax relays seem a bit much, make a coax patch panel and 
use coax jumpers to configure for the mode you want.

>  Oh, don't forget there are some birds with HF
>links and the SoftRock can do HF natively too...
>If only I had the time to work on such a thing...
>Ideally, the transverters would be dual frequency, so that you could tune
>to 432 terrestrial or 435 satellite; 1269 satellite or 1296 terrestrial;
>and 2304 terrestrial or 2400 satellite.

With the newest xvtrs using PLL in place of xtal oscillators; this is 
a dc switch to shift LO's.  I am installing PLL's into my 1296 and 
3400 DEMI xvtrs.

>Newer DEMI transverters with the
>synthesized LO board can be configured that way, at least on the higher
>bands. Then you'd have not only a kick-@$$ satellite system, but also an
>outstanding weak-signal terrestrial system.

DEMI is planning for PLL from VHF up (when they can get to it).  PLL 
available now 1296 and up.

>Unfortunately, DEMI is once again revamping their lineup of products. Of
>course, this is good for us who want the latest and best, but bad for us
>who want something right NOW. Prices and specs are a little bit harder to
>obtain from DEMI right now, but I expect that the wait will be worth it.

Prices are announced on the webpage.  Some of the xvtrs are shipping 
in June (I have 144/28 ordered).  They are shipping assembled units 
first, then will offer kits later in the summer.

73, Ed - KL7UW, WD2XSH/45
BP40IQ   500 KHz - 10-GHz   www.kl7uw.com
EME: 144-600w, 432-100w, 1296-60w, 3400-fall 2010
DUBUS Magazine USA Rep dubususa at hotmail.com

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