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Hi Guys,

I'm looking for any info on this reciever, my main aim is the RSSI pin but any info will be usefull.

post-5-1188844474_thumb.jpg

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this one is from RC-tech !

is simply called "2.4GHz receiver"

it has a really hi sensitivity ! visible better than anything else I have seen,

it is specially designed for longest range possible with 10mW transmitters,

that is the max legal power many places,

how ever mine have a white balance problem when the monitor is not DC coubled or 75 ohm loaded, I dont see the same problems with my comtech receivers,

but did not investergate futher in what cased the trouble, maybe my monitor is wierd on the video input, since I know many users are happy with this receivers performance.

first 4 channels are compatible with airwave and comtech stuff as usual.

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Thanks Thomas, you are right about the sensitivity ! I hope to use 4 of them for another 4 way diversity system, thats why I need the RSSI pin. Mine too seems to have poor video with one of my monitors which is odd as it's fine with others and the monitor is fine with other receivers. Anyway not a big problem.

Terry

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Hi Terry,

i have the same receiver, got it for 10 bucks on a flea market. It was still in its package and as i remember it should be from ZTV (ZT 707).

Hope this helps,

Sibi

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Yes that seems to be it Sibi, thanks.

Can anyone confirm that the RSSI can be taken from the yellow wire marked BB I/P ?

Terry

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Can anyone confirm that the RSSI can be taken from the yellow wire marked BB I/P ?

Nope. That wire is what carries the muxed video/audio signals (baseband signal). IF RSSI is available, it would be one of the unconnected pins.

Edited by Kilrah

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Ahh, thanks Kilrah, I had my doughts thats why I asked ;)

I can't find it on any of the unconnected pins which is a shame.

Terry

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While we're discussing this 'black horse' of the receiver world, is there an easy way of wiring in a switch to change channels, and keep that channel between uses?

I tend to just use one channel most of the time - no, not channel 1 :P - and being able to set this with a hard switch this would mean there is one less thing to do from the list of 5 million things to worry about before chucking that FPV 'plane off a cliff....

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You could use a PIC that would send the correct number of low pulses at power-up? :P

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Yep, silly as it sounds. A pic that monitors the led's and sends pulses to the switch so that it matches a dip switch would be simple.

Terry

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If you don't have the resources to create a microcontroller (PIC) solution, then you could use a small piezo buzzer and three steering diodes. Basically, it would scream at you until it was set to the "home" channel. If you need to occasionally use other channels, then add a inline switch to kill the noise. :)

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Yep, silly as it sounds. A pic that monitors the led's and sends pulses to the switch so that it matches a dip switch would be simple.

Terry

Hey that's high-end! I didn't even go as far as monitoring, just a few delays and a minimum of connections :L

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Hey that's high-end! I didn't even go as far as monitoring, just a few delays and a minimum of connections :L

What do you expect from Albert Terry Einstein :lol:

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You're all quite PIC mad :blink: ...

Your replies also suggests that the channel number is programmed down a serial link (or something equally inaccessible) which you're not suggesting reverse-engineering. I was wondering instead if the button switches across 4 channel pins (which are also connected to the LEDs)?

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We are suggesting that it would be easy to use the push button input connected to the PIC and use that as the input device. I also suggested using the led outputs to tell the PIC which channel it was on.

Terry

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Your replies also suggests that the channel number is programmed down a serial link (or something equally inaccessible) which you're not suggesting reverse-engineering. I was wondering instead if the button switches across 4 channel pins (which are also connected to the LEDs)?

Nope, not that complicated. The receiver simply has a pushbutton input and 4 leds, and will switch to the next channel each time the button is pressed as you must have noticed.

Our less than clever solution was simply to connect the PIC to the pushbutton. If you want to start say on channel 3, have the PIC simulate 2 button presses at each power-up. As simple as that :P

The "PIC reflex" must come from the fact that I have more than 100 of these small things in a box, and that it would take less time to program that function in one than to open the receiver and solder it in place ;)

Edited by Kilrah

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Okay, I'm clearly just being old-fashioned! And yes, I am finding increasingly these days that just opening up electronic things can destroy them; a video spiltter I bought off eBay, when I undid the front panel to see if I could adjust the supply voltage, glue on the back of the front panel ripped off the wiring loom.

I would love a box of diddy PICs to do my bidding, instead of faffing around with logic chips, op-amps and so forth. Is there a simple PIC, programmer and programming environment you'd recommend for knocking up this sort thing?

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http://www.microchipdirect.com/productsear...ywords=DV164120

Check the second item. There's even the development software (assembly and "light" C version) on the CD :)

I regularly use some 8-pin 12F675s for that kind of stuff, or the 14pin 16F676 which has the exact same features if I lack I/Os.

Edited by Kilrah

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I use 12F675's too, very good but as Kilrah said lack of IO's can be a problem. Have a look at QUASAR ELECTRONICS in the UK for programmers. I may even go the dip switch route myself soon.

Terry

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Might also want to look at an Atmel STK500 - just a different brand of micrcontroller :) You can also get the AVR ISP mkII if you want to do programming over USB rather than serial.

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OK, I did it as Kilrah said, just pulse through to the correct channel, no LED feedback to the PIC. I just wanted to add the auto channel with minumum fuss, only 3 wires to the 12F508. I think I was getting carried away :D

Now at power on it will step to the channel selected by the DIP switch and the channel button still works as before. So the only change is that it will start on the channel you select instead of channel one every time. No need to access the DIP switch from outside if you dont want to drill a hole :)

I also found the RSSI but you need to open the can. I connected mine using one of the original (unused) pins from the can.

Terry

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I set up 4 of these on my new 4 way diversity/switching system and found poor results. 1 was good 2 fair and 1 hopeless! the clue to the problem was with the hopeless receiver, it picked up ch4 better when set to ch3. This told me the problem was with the frequency it was receiving so I opened up the can to have a look. Inside I found a small 3 turn coil of enamaled wire and by adjusting it I could adjust the frequency. With this adjusted the performance rocketed, I could now receive my test transmitter even without an aerial connected :)

The adjustment of this coil is very critical for good performance so I guess its easy to knock it out if it is dropped or handled bad. Look after your receiver well :huh:

The bad news is its hard to get it right with no test gear, I found the best way was to connect video loss detector with LED and adjust it to give the most solid light.

Terry

Edited by Terry

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