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--- guides:radio_modules [2012/04/03 15:39] – [HX1] nigelvh
+++ guides:radio_modules [2015/06/11 07:51] (current) – upu
@@ Line 1: / Line 1: @@
-====== Radio Modules ======
+====== Radios ======
+There are a number of radio modules in use with descriptions :
+^ Module     ^ Price ^ Temp Stability ^ Complexity ^ Size/mass^ Frequency ^ Modulation ^Further Information^
+| Radiometrix NTX2 | Medium| Poor | Simple | Medium | 434.075 or 434.650 | FM (analogue) | [[guides:radio_modules:NTX2|Data]] \\ [[guides:linkingarduinotontx2|Linking an Arduino to a Radiometrix NTX2 Transmitter]] \\ End of life|
+| Radiometrix NTX2B | Medium| Excellent| Simple | Medium | 434.000 -> 434.750 | FM (analogue) | [[guides:radio_modules:NTX2|Data]] \\ [[guides:linkingarduinotontx2|Linking an Arduino to a Radiometrix NTX2 Transmitter]] \\ Breadboard friendly pitch|
+| Radiometrix MTX2 | Medium| Excellent| Moderate| Low | 434.000 -> 434.750 | FM (analogue) | [[guides:radio_modules:NTX2|Data]] \\ [[guides:linkingarduinotontx2|Linking an Arduino to a Radiometrix NTX2 Transmitter]] \\ Effectively identical to the NTX2B|
+| Radiometrix LMT2 | High | Excellent | Simple | High | 433.900 -> 434.650 | FM (analogue) | [[guides:radio_modules:LMT2|Data]] \\ Superseded by MTX2|
+| Radiometrix TX3H | ? | Poor | Simple | High | 869.50Mhz | FM (analogue)  | [[guides:radio_modules:TX3H|Data]]|
+| Radiometrix HX1 | Medium | Good | Moderate | Medium | APRS 144.800/143.900/144.390 | FM (analogue) |[[guides:radio_modules:HX1|Data]]|
+| HopeRF RFM22B | Low | Poor | Moderate | Low | 413.000 -> 453.000 | FSK (PLL) + others |[[guides:rfm22b|RFM22B]] \\ Insulation is very important with this module, the crystal is only rated to -20'C. The module has exhibited instability and failure when exposed to low temperatures. It is recommended to reboot the module every 20 telemetry transmissions.| Not suitable for long duration flights without lots of insulation.
+|CC1101/CC430 (bare IC)|Low|Depends on crystal|Software:Moderate; Hardware:Moderate| Lowest |434 & 869 ISM|FSK (PLL) + others; FM (analogue) with external components|[[http://www.ti.com/product/cc1101|datasheet (cc1101)]], [[http://www.ti.com/product/cc430f5135|datasheet(cc430)]], [[http://uk.farnell.com/johanson-technology/0433bm15a0001e/balun-433mhz-impedance-matched/dp/2148531|single component match and filter]] CC430 comes with MSP430 processor for overall smallest area|
+Notes :\\
+"Poor" stability means unless well insulated the frequency will drift noticeably. \\
+"Simple" Complexity means suitable for beginners. \\
+All modules support RTTY, analogue FM ones support APRS via external DAC
-===== NTX2 =====
-The [[http://www.radiometrix.com/|Radiometrix NTX2]] is the main radio transmitter module in use for UK HABing - it is available in 434.075 and 434.650MHz variants. The NTX2 is a 3V Narrowband FM module and primarily chosen for its data input characteristics - which are analogue rather than the more usual digital.  This enables narrow frequency shifts and pulse shaping to be obtained. Output is 10mW. Current draw is 20mA when transmitting and 0.6mA in standby. The input voltage to frequency characteristics of the NTX2 are reasonably linear at around 1.9kHz/V about the 1.5V input centre point - see graph below. The graph shows frequency offset (kHz) against data input voltage over the 0 - 3V range.
-{{guides:ntx2.jpg|}}
-The regulatory requirements for airborne operation on this frequency are that the channel bandwidth must be less than 25Khz and less that 10mW ERP (Effective Radiated Power). There are no duty cycle requirements in this frequency band.
-The NTX2 temperature stability isn't great - in addition to drift the frequency shift tightens up with decreasing temperature.
-**NTX2 Adjustments**
-Removing the sticker from the NTX2 package reveals 3 holes in the metal casing - 1 test point (I haven't checked what it is) & 2 adjustments.
-With the module oriented such that the holes are facing you & the pins facing downwards, the upper adjustment screw is frequency adjustment - perhaps adjusting loading on the crystal. Testing with a 434.650MHz NTX2 I was able to push the frequency about 15kHz either way before the oscillator became unstable.
-The lower adjustment screw seems to be a pot adjusting the [[http://en.wikipedia.org/wiki/Frequency_deviation|deviation]]. With the voltage driven FSK implementation we use, this conveniently allows for fine tuning the shift.
-===== TX3H =====
-The TX3H is a Radiometrix 869.5MHz module which provides 450mW of output (up to 500mW is allowed for airborne use in this frequency band). The TX3H is a 5V Wide-band FM module which like the NTX2 has analogue input on the data pin. The input voltage to frequency characteristics of the TX3H are shown in the graph below - and is approximately 11kHz/V about the 2.5V input centre point. The graph shows frequency offset (kHz) against data input voltage over the range 0 - 5V.
-{{guides:tx3ha.jpg|}}
-TX3H temperature stability is worse than the NTX2 (as might be expected of this higher frequency module) - also noticeable heat is generated by the module due to the higher power and lower efficiencies at higher frequencies.
-The regulatory requirements of airborne operation in this band are a channel bandwidth of less than 25kHz, less than 500mW ERP and less than 10% duty cycle. The latter requirement reduces the heat dissipation issues.
-===== HX1 =====
-The HX1 is a Radiometrix 2m module which provides 300mW of output. The HX1 is a 5V Narrow-band FM module. The module appears to come in two versions, the HX1-FREQ-3 and the HX1-FREQ-10. This information is based on tests of the HX1-FREQ-3 model. Deviation in the Audio Frequency range does not appear to be very linear. Below is a chart of the relative audio frequency response of the module. More information concerning the testing set up can be found here: [[https://k7nvh.com/wordpress/?p=123]].
-{{guides:hx1_af_response.jpg|}}