trebor Posted July 16, 2018 Share Posted July 16, 2018 Has anyone tried one of these yet ? **LINK** Just thinking it might be ok for a couple of quads running Spektrum satelites and a small foam as3x indoor plane I have left to convert to Frsky. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted July 16, 2018 Share Posted July 16, 2018 wow, if that works it would be an amazing bit of kit! BEB Quote Link to comment Share on other sites More sharing options...
trebor Posted July 16, 2018 Author Share Posted July 16, 2018 Oppps Edited By trebor on 16/07/2018 18:23:53 Quote Link to comment Share on other sites More sharing options...
trebor Posted July 16, 2018 Author Share Posted July 16, 2018 Posted by trebor on 16/07/2018 18:22:08: I thought it might be good with some of those cheap toys for flying about indoors, not much information about it yet appart from this **LINK** Ps, I went for this as it states it workes on Dsmx. Pps, Oppps again ! Edited By trebor on 16/07/2018 18:25:09 Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted July 16, 2018 Share Posted July 16, 2018 Hmm! RF Power = 22dBm. That corresponds to 158.5 mW. Add in the 2dB gain of a standard aerial and that takes you to 251.2 mW! That's way over the 100mW legal limit. Its even over the 200mW American limit! Now from a purely technical point of view, I don't see a problem with this. However, should Ofcom ever investigate, you would be in a very sticky position legally. You pays your money and you takes your chances. (To be legal, the output power should be 18dBm, for use with a standard 2dB gain aerial). -- Pete Quote Link to comment Share on other sites More sharing options...
trebor Posted July 16, 2018 Author Share Posted July 16, 2018 I knew there would be a catch Quote Link to comment Share on other sites More sharing options...
Mike Blandford Posted July 16, 2018 Share Posted July 16, 2018 This all started out as a DIY project, see: **LINK** The firmware on the module is open source, see: **LINK** The transmitted power may be adjusted in a header file of the firmware. Mike Quote Link to comment Share on other sites More sharing options...
Mike Blandford Posted July 16, 2018 Share Posted July 16, 2018 I doubt they actually know what the output power is! There are 4 RF chips in the module and a single power amplifier. On my DIY module I notice the RSSI readings when using FrSky protocol are lower than when using a real FrSky XJT module, so I reckon the output power for that is lower. The chip for FrSky (CC2500) can output a max of 1dbm (before the power amp.). The maximum for the NRF chip is 0dbm, the A7105 is 1dbm and the CYRF chip (for DSM) is 4dbm. Mike Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted July 17, 2018 Share Posted July 17, 2018 Mike: Yes, I suspected there must be some way of adjusting the RF output in firmware, as otherwise all the manufacturers would have the same problem. But I confess to not knowing enough about programming these chipsets to know how to do it! From a purely technical point of view, I don't have a problem with the power outputs - other than it being unnecessary and wasting battery power. A friend of mine has managed TWO MILES of GROUND range on a buggy with a standard Taranis at 100mW! Anything more is clearly a waste, IMHO. However, it could be problematic legally. I see Immersion RC are now producing an RF power meter that is claimed to be accurate over most of the modelling bands, including 2.4 GHz. I'm tempted to buy one, but although it covers 433MHz, it doesn't mention 459MHz, which would be of prime interest to me. I can measure power on my spectrum analyzer, but its very old and I can't vouch for its accuracy. Having said that, I did measure a DSX-9 on it when they came out at first, and it measured bang on 18dBm, so maybe its not too far out..... Might be worth investing in one of these modules just to check it out... -- Pete Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted July 17, 2018 Share Posted July 17, 2018 Peter, would that Immersion RC RF power meter be any good to determine erroneous RF signals on our flying site or is it really only for checking the TX RX ? Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted July 17, 2018 Share Posted July 17, 2018 Posted by Ron Gray on 17/07/2018 08:41:33: Peter, would that Immersion RC RF power meter be any good to determine erroneous RF signals on our flying site or is it really only for checking the TX RX ? Ron, you can get a 2.4gig RF checker app on a smartphone, then stand in the pilots box and be amazed at the signals received Edited By Denis Watkins on 17/07/2018 08:57:48 Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted July 17, 2018 Share Posted July 17, 2018 Ron, I haven't held one in my hands, but from what I read it appears to be purely for measuring the output of transmitters rather than acting as a monitor. As Denis says, there are RF Checkers available on smartphones, but these tend to be limited to the protocols the smartphone understands (WiFi rather than RC). They can give a useful indication of what is around, though. If you want a full on monitor, something like this may be more useful: **LINK** Not cheap, but it will show you exactly what is on the 2.4GHz band. Only really useful when there are no Txs switched on, as a frequency hopping Tx will promptly fill the display up - but a good indication of whatever else is around. There are other (more expensive!) versions which cover more bands. I got one that covers all our model control bands from 27 MHz to 459Mhz (and beyond!), 2.4 GHz and 5GHz. It has produced some interesting results on occasions! Mine is probably a bit heavy duty for an individual, but as I do quite a bit of RF work, I could justify it. Probably more realistic as a club purchase. Indeed I think the BMFA have a couple that they will lend to affiliated clubs who are having problems. -- Pete Quote Link to comment Share on other sites More sharing options...
Mike Blandford Posted July 17, 2018 Share Posted July 17, 2018 To flash new firmware to the module you compile it using the Arduino IDE. All the power settings are included in the file "multiprotocol.h" like: enum CYRF_POWER { CYRF_POWER_0 = 0x00, // -35dbm CYRF_POWER_1 = 0x01, // -30dbm CYRF_POWER_2 = 0x02, // -24dbm CYRF_POWER_3 = 0x03, // -18dbm CYRF_POWER_4 = 0x04, // -13dbm CYRF_POWER_5 = 0x05, // -5dbm CYRF_POWER_6 = 0x06, // 0dbm CYRF_POWER_7 = 0x07 // +4dbm }; #define CYRF_HIGH_POWER CYRF_POWER_7 #define CYRF_LOW_POWER CYRF_POWER_3 #define CYRF_RANGE_POWER CYRF_POWER_1 // 1/30 of the full power distance #define CYRF_BIND_POWER CYRF_POWER_0 So to reduce the output for the CYRF chip (used for DSM) just change the line: #define CYRF_HIGH_POWER CYRF_POWER_7 to #define CYRF_HIGH_POWER CYRF_POWER_6 Mike Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted July 17, 2018 Share Posted July 17, 2018 Thanks for that info, Mike. I really ought to get into this stuff a bit more, but my programming days came to an end with 8-bit 6502s - as far as machine code goes, anyway! I can follow Arduino code enough to modify it when required, but would hesitate at writing from scratch! Oh, dear! I can see another learning curve on the horizon.....! -- Pete Quote Link to comment Share on other sites More sharing options...
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