I got a new Sombra programmable rx (www.sombralabs.com) from Barry Kennedy today.
It's a double-conversion PPM unit that doesn't have a crystal; you program it to the desired channel with an external gizmo that plugs in, does its job, and then unplugs. The rx itself is a tiny board (8 grams) with the necessary connectors, an inductor potted in plastic to look sort of like a bypass capacitor, and (apparently) three ICs. One seems to be the front end/mixer, one (possibly) handles the two IFs, and one is a DSP chip. I'm guessing, of course, but I think that's it. The front end is hugely broad; my rx can be programmed across both the 50 and 53 mhz r/c frequencies, which sounds a bit alarming. However, the selectivity comes after the front end. Sensitivity is rated at better than 2 microvolts. There are no specs regarding adjacent channel rejection or such, so it'll be interesting to see what tests we users can do (Tom Hoopes, are you listening?). All I've done so far is to set it to 53.2 and range check it. Programming is a no-brainer, taking only a few seconds: set programmer, plug in, press button, remove. The range seems fine. I'll know more when I get it in a plane and give it a real try in the presence of other signals. If it works, it'll be a boon to those who fly on the ham frequencies. Of course, Sombra makes it for the 72 mhz band too, but I was particularly interested because my supply of ham receivers was interrupted. FMA used to make an 8-channel double-conversion rx for ham bands, but discontinued it and makes only a 6-ch now -- and it isn't the right 6 channels for my JR10x's 6-servo setup. Sombra has also announced a 9-channel xtal version coming next year. A lot of heavy-duty functions of a receiver can be done with ingenious DSP programming; ham transceivers from Icom, Yaesu and Ten-Tec have proved that. So even though this little board has no components that look like RF components, I'm willing to believe that it'll do the job. If so, it would be a great rx for any sailplane application, especially HLG. I'm optimistic. Barry or the sombra website can provide more details for those interested. RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
