Thanks Tim for the reply and thanks for the links. I've read all those links before. I think I have read nearly everything there is to read, including development history and the manual. Granted, I could have missed or skimmed over the details I am looking for. BTW- I'm a 55 year old mechanical engineer and an Amateur Extra class, AC8DE.
My first question is on the uplink/downlink frequencies. It simply states 433 MHz. I assume this to be an approximate frequency in the 70 cm band and not the actual exact frequencies. Rarely is something right at 433.000 MHz. Are there separate uplink and downlink frequencies (full duplex) or does it switch on/off transmit/receive at each transceiver (Telmetrum and Teledongle) using the same exact frequency. Is the frequency(ies) movable in case of frequency conflict and RFI? How wide is the data bandwidth in KHz? I happen to have a commercial radio (HBC Radiomatic) in my launch system design that uses, yep... the 433 frequency range. I can select 4 discrete "channels" on it to help it avoid any conflict, but it would be good to know where the Telemetrum actually transmits and receives so I can shift the launcher away from that frequency as far as possible. Then there is the case of what if there is another Telemetrum or two around the launch site; a very probably scenario. (I think they are all coded and using "telegraph" messaging handshaking to avoid conflict with another Telemetrum, but I could be wrong.) I could figure most of this out with a spectrum analyzer, but I'd have to buy it first and then spend the time to test. Better to know these technical details before I buy. I see there is a starter "kit" that uses the Teledongle. But there is also the TeleBT, which seems to do everything the Teledongle does, PLUS adds bluetooth for use with the Android App. It seems that starting with the TeleBT would the better choice and don't even buy the Teledongle, but I wanted to make sure I wasn't missing something on this. I saw the history on older versions with the problems with pyro events and battery rail sag and that it is supposed to be solved now. (An age-old problem on many avionics packages.) I think I'd rather put a second LiPo on the Telemetrum and give the pyro events their own rail and simply avoid any potential rail sag issue. Just a small LiPo should do the job. I'm guessing others have done this and I read where that is an option on the board. I'd like feedback on that. I read where there is an SMA connector option for the Telemetrum. I've considered ordering the Telemetrum with that option and make the antennas a permanent part of the Avionics bays fed with a short piece of RG-316 or the like. Of course downside is mass of the connector soldered to the board and having to support the feed line to account for high-G conditions so the connector isn't broken from the board. I'd like some feedback and discussion on the use of the SMA connector. I can't figure out how to order the Telemetrum with that option anyway. Perhaps it is a field mod? Thanks, Scotty From: altusmetrum [mailto:[email protected]] On Behalf Of Tim Cubbedge Sent: Thursday, April 13, 2017 8:53 AM To: 'Altus Metrum' Subject: Re: [altusmetrum] New Member Have you looked here? http://altusmetrum.org/AltOS/doc/altusmetrum.html or here? http://altusmetrum.org/TeleMetrum/ What do you want to know? From: altusmetrum [mailto:[email protected]] On Behalf Of Scott Myers Sent: Thursday, April 13, 2017 7:11 AM To: [email protected] Subject: [altusmetrum] New Member I just joined this Altus Metrum mailing list. I'm trying to get a bit more information and learn more about the Telemetrum before I purchase one. Thanks, Scotty
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