VX-6R dies when TXd on certain freqs

[nzoliver]

Hi all,

Why would my VX6R cut out and need to be plugged in to the mains to reset. This happens with the FM radio band and TX freqs over 490Mhz.

Anyone have a clue?

Thanks

Oliver

 

[Grog]

Anyone have a clue?

Yeah, but you don't

 

[43g70]

It is designed to transmit only up to 450 Mhz and not above.

When you modify it with the MARS/CAP mod, it can only go so far before the Radio will give up.

43g70

 

[kg4uad]

Hi all,

Why would my VX6R cut out and need to be plugged in to the mains to reset. This happens with the FM radio band and TX freqs over 490Mhz.

Anyone have a clue?

Thanks

Oliver

"plugged in to the mains"? Plugged into the wall charger? I have 2 modified VX-6R's and have never seen this issue. Did you do a "reset" when you did the modification? What is your displayed voltage upon power up? 490Mhz with the stock rubber duck will no doubt produce a extremely high vswr, please tell me you didnt transmit very long.

 

[XTS3000]

490 is so far out of band, the PA is sucking up so much current to attempt to produce RF output, either the li-ion battery is dropping below 4.5V. Once the battery pack detects voltage below 4.5V, it shuts off the battery. If the li-ion battery is taken any lower than 4.5V, it may never take a charge again.

Li-ion batteries are sensitive to low voltage, as well as over voltage. Thats why there are lots of federal regulations on li-ion batteries. If li-ion batteries are over charged, they blow up with almost the force of C4. Thats why every li-ion battery must contain a regulation circuit for overvoltage & undervoltage detection.

Another thing that could cause the radio to freak out, is at 490mhz, your swr's are so high, there is very little power making it out the antenna. Most of the power generated by the PA, is being reflected back into the PA/Radio. This high level of RF inside the radio may be scrambleing up the CPU - causing undesired operation.

 

[obijohn]

Another thing that could cause the radio to freak out, is at 490mhz, your swr's are so high, there is very little power making it out the antenna. Most of the power generated by the PA, is being reflected back into the PA/Radio. This high level of RF inside the radio may be scrambleing up the CPU - causing undesired operation.

In my experience, that frequency is outside of the lock range of the transmitter VCO, that is why it fails. It goes without saying that it is outside of the type acceptance of that particular radio, so you just have to live with it.

If you had a service manual for that radio,it might be possible to tweak the VCO lock range up in frequency-but you will sacrifice lock range at the low end.

 

[KF4TKP]

Has anyone messed with the VX6 values for TX power under 220mhz? Curious if it is capable of more than 1.5W ?

 

[nzoliver]

Hi all,

Apparantly this is an issue with a few of them reading the interweb!
Some (and I have seen them do it) TX right up to 512Mhz!! I'don't think there would be much power there or be very good for it but...
It depends on the version..EXP B3 is supposed to be OK but you have to have the right blobs soldered. #2 + #5 according to the data sheet I found.

My 10c worth.

 

[W6KRU]

Hi all,

Apparantly this is an issue with a few of them reading the interweb!
Some (and I have seen them do it) TX right up to 512Mhz!! I'don't think there would be much power there or be very good for it but...
It depends on the version..EXP B3 is supposed to be OK but you have to have the right blobs soldered. #2 + #5 according to the data sheet I found.

My 10c worth.

You revived an almost 2 yr. old thread to add that? :roll: