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Can DPCAV delux 900mhz video Rx be converted into 1280mhz?

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Hi Thomas,

                          Wondering if its possible to convert the "900MHz A/V Receiver, Deluxe Model with Comtech Tuner" thats available on your website?I want to buy 1280 video Rx but they are not available.Please suggest.Thanks.

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Possible? Yes.  Practical? Not really.

The Racewood 900MHz and 1280MH VRx have the same hardware. The Comtech tuner's operating frequency is handled by a microcontroller on the baseband PCB. So the firmware is different. Unfortunately the microcontroller is soldered in place and is not re-programmable.

It's possible to disconnect the two wire I2C bus from the Comtech tuner and use an Arduino microcontroller (and your custom software) to control the frequency. I don't have any project links on doing this, but maybe Google will help you find some useful information.

 

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Thanks for your reply.

Actually pitlab diversity controller can send i2c signals to change the frequency on the tuner.May be i should buy and try:)

One more thing,has the tuner been modified with saw filter to use it with dragonlink 433mhz?

If the microcontroller is somehow re-programmable,then i can try to desolder it. 

 

I am looking for a quality video product like you sell on DPCAV and that's why i don't mind trying to mod only it if its possible.

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It has the stock 27MHz SAW filter. You could de-solder it and replace with a ECS-D480A (17MHz SAW).

The microcontroller is OTP (one time programmable). It's a Chinese clone of an old Microchip Technology part. I don't recall the part number.

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I looked inside my old Racewood "900MHz A/V Receiver, Deluxe Model with Comtech Tuner" and it uses a Microchip Technology PIC16C55A microcontroller. The chip is a 28 Pin DIP package.

I also looked inside my Racewood "Standard Receiver" (small tan colored metal box model). It has a SOIC-18 SMD packaged PIC16C54C microcontroller. But I also recall they used a Chinese clone of that part in some production lots (it was a direct replacement IC).

These microcontrollers were programmed with Racewood's firmware, which is proprietary. So I don't have the source code.

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Thanks Thomas for looking. I can control the frequency with pitlab controller then.

So now I want to try one Rx first from you and will mod it with your saw filter.

But one thing is confusing for me is that i have a no name 1.3ghz chinese rX which doesn't have comtech tuner and i get terrible interference from 433mhz dragonlink.But i opened the tuner cover,its fitted with F480-1. So looks like its fitted with proper saw filter and i am still getting lots of interference where as my RMRC 1.3 Rx doesn't show any interference.Does that mean there are other components involved to get rid of 433mhz interference?Please suggest.Thanks.

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This is the info from RMRC website:

Quote

RF module and supporting circuitry hardened to improve resistance to UHF RC signals such as Dragon Link, Crossfire, EZUHF, and others. Other receivers on the market can lose the video signal completely when in close proximity to UHF RC transmitters.*

 

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But one thing is confusing for me is that i have a no name 1.3ghz chinese rX which doesn't have comtech tuner and i get terrible interference from 433mhz dragonlink.

The BSS-479 Comtech tuner module is a better design than the lower cost Chinese made "clone" tuner modules. Plus the overall design of the FPV receiver is important too.

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But i opened the tuner cover,its fitted with F480-1.

The upgraded SAW filter's effectiveness depends on many circumstances. I normally recommend the SAW filter upgrade as a way to increase vRx sensitivity rather than promote it as cure for bad UHF noise. But if the original SAW filter is a poorly manufactured component then replacing it could help out a lot.

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So looks like its fitted with proper saw filter and i am still getting lots of interference where as my RMRC 1.3 Rx doesn't show any interference.

If you are having success with the RMRC vRx then I highly recommend you choose another one if you are expanding your ground station. A bird in the hand is worth two in the bush.

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Does that mean there are other components involved to get rid of 433mhz interference?

EMI/RFI noise is cruel. Sometimes the cure is as simple as rerouting a cable or moving the offending RF source further away. Or maybe adding a capacitor at some strategic place on the circuit board will help. Or improving the RF grounding on the metal case. Or adding EMI/RFI filtering to all the external A/V signal & Power entries. The list goes on. And sometimes a practical cure is impossible, other than replacing the inadequately designed RF device.

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I don't know what they mean by "hardened" :)

I'm not a RMRC receiver user, so I have no idea what they may have done to improve the receiver's resistance to UHF interference. But if it has a Comtech tuner in it then that is certainly a big advantage.

 

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Thanks Thomas for the detailed explanation.I wish you have any 1280 Mhz Rx in stock.

I am tempted to try out your 900mhz Rx and will try to replace the saw filter on it.

 

I really appreciate your honesty in providing proper details and not trying to just sell your product.Also i have couple of your products working flawlessly from the years!!

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I wish you have any 1280 Mhz Rx in stock.

Sorry, but those wonderful vRx's are no longer available. It was a sad day when Racewood closed their factory.

 

Quote

I am tempted to try out your 900mhz Rx and will try to replace the saw filter on it.

That's an option. But you mentioned that you have a Chinese vRx that has bad UHF interference. Maybe there is a solution? What have you done so far to solve it?

 

Quote

I really appreciate your honesty in providing proper details and not trying to just sell your product.Also i have couple of your products working flawlessly from the years!!

Thanks for your kind words. I appreciate the feedback.

 

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I haven't done anything yet with the chinese no name Rx as i wanted to have comtech tuner.I  was thinking that its just a saw filter that i need to replace but when i opened it,,F 480-1  was already there.

Maybe just comptech module with good saw filter can solve the problem. Do you have any comptech module that i can buy.Then i will modd it with your proper saw filter and can tst it it interferes with UHF.

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The Comtech BSS-479 is no longer made and has sold out. RMRC was also selling them, so maybe they can help?

 

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