Comtech BSS479LAIDF Analog Tuner Module $19.95 http://www.dpcav.com/xcart/Comtech-BSS479LAIDF-Analog-Tuner-Module.html http://www.rc-cam.com/forum/index.php?/topic/3672-comtech-tuner-module-upgrade Using the $50 Digital Scope to Measure Video Levels http://www.rc-cam.com/forum/index.php?/topic/2825-using-the-50-digital-scope-to-measure-video-levels Micro Diversity controller $22.00 http://www.rangevideo.com/index.php/micro-diversity-controller.html http://www.rcgroups.com/forums/showthread.php?t=1330314 http://www.fpvhub.com/index.php?topic=1367.0 http://www.rcgroups.com/forums/showthread.php?t=1346671 Build your own diversity controller (IBCrazy) http://www.rcgroups.com/forums/showthread.php?t=1169075 ---------------------------------------------------------------------------- 2 -> Analog 0-5V RSSI level Grn/Org 3 -> 5V regulated logic power Red 4 -> BB / Baseband out (mixed video + sound subcarrier) Blue 5 -> SDA / I2C DATA White 6 -> TUV / 9V PLL charge pump power (>9V for >1500MHz) Yellow 7 -> SCL / I2C CLOCK ---------------------------------------------------------------------------- http://www.rc-cam.com/forum/index.php?/topic/3672-comtech-tuner-module-upgrade/?p=26205 From left to right, antenna on the left side, "ComTech" brand (and white BSS479LAIDFM sticker) on top. __------------ Antenna-__ | | | |___________| 1 234 56789 1 -> LNB or LNA power supply (only needed if you want to feed a preamp powered by coax cable) 2 -> Analog 0-5V RSSI level 3 -> 5V regulated logic power 4 -> Baseband out (mixed video + sound subcarrier) 5 -> I2C DATA 6 -> 9V PLL charge pump power (>9V for >1500MHz!) 7 -> I2C CLOCK 8 -> not needed (PLL programmable out) 9 -> not needed (PLL programmable out) Ground is the metal case. Remove the old tuner Use a multimeter to find 5V and 9V Use a headphone to find baseband (white noise) Use a headphone to find I2C data and clock (typical data burst noise only when you change the channel switch) Reverse I2C data and clock if the RX frequency dont change. 10 minutes operation and no risk for your baseband board IF you're used to "DIY". Pascal ---------------------------------------------------------------------------- Sunsky original module: Grn/Org -> Vcc: 4.99V Red -> BB: 2.30V Blue -> SDA: 0.03V White -> TUV: 9.12V Yellow -> SCL: 0.02V Comtech module: Grn/Org -> Vcc: 5.00V Red -> BB: 2.83V Blue -> SDA: 0.04V White -> TUV: 9.12V Yellow -> SCL: 0.03V (RSSI: ~4.3V) Supply = 12.23V At 08:43 PM 11/11/2013, support2009@dpcav.com wrote: I will send out another Comtech on Tuesday Nov 12 to see if that solves the problem. I am concerned about your i2c signals. In fully compliant designs the SDA & SCL would be logic high (~5V) during idle buss activity. However, your SDA and SCL are logic low (0V). So the firmware in your vRx might not provide reliable communication with a Comtech Tuner. Hopefully this observed quirk is not an issue for the Comtech. ---------------------------------------------------------------------------- http://fpvlab.com/forums/showthread.php?6872-Checking-in-from-Northeast-US&p=466603&viewfull=1#post466603 ET: Yeah, the cheap video receivers that come with some of the transmitters can be wonky. I've successfully upgraded the module in one of these to a Comtech module; seems to work well. I followed these directions (he makes a big deal out needing to "re-adjust the video amplitude/level using the pot on the baseband PCB," but my unit didn't have that pot and works fine; I think the adjustment is done automatically on newer receivers). The $80 ReadyMadeRC receiver is nice; it also has a SAW filter (for less interference from UHF control signals). The listing says "now shipping with high quality Comtech tuners in every model," it didn't say that when I got one a few months ago. I use one of these and a one of the cheap receivers (upgraded with a Comtech module) in a diversity setup via the $22 RangeVideo Micro Diversity controller. For this setup you need to run an RSSI signal wire out from the module in each receiver. --ET