VK Logger Ham Radio Forum Archive

I recently purchased a TYT TH-9800 quad band radio from overseas. At US$297 (including shipping) it seems a fairly good deal. The only problem is that they come with a fairly wide transmit range which, I'm sure, wouldn't impress the ACMA. By default, they TX between 26-33MHz, 47-54MHz, 134-174MHz and 400-480MHz. Note: Radios purchased from an Australian supplier should (hopefully) already have the correct limits set.
Programming software is available from the TYT Electronics web site which lets you configure just about everything except the transmit range. However, all is not lost. The following method can be used to modify the transmit range.

If you have a brand new radio which you haven't done anything to yet you can just get the data file from here which has the correct limits set. Simply load this into the TH-9800 programming software and send it to your radio.

If you want to change the limits yourself then you'll need to edit the data file that's saved by the TH-9800 programming software. I use a program called HxD Hex Editor (do a Google search for HxD). The TX/RX limits are stored near the end of the file between 0x10F30 and 0x10FBF.
Just change the transmit limits to the required values.
You can then open the file with the TH-9800 programming software, check that the TX limits are correct and send it to your radio.

Hi Ian,

I'd be really interested to hear your thoughts on this radio after a bit of use.


I'm not sure if it will work on the TYT, but CHIRP is often the best software to easily lock down Chinese radios to the Ham bands.

VK3DXE wrote:I'm not sure if it will work on the TYT, but CHIRP is often the best software to easily lock down Chinese radios to the Ham bands.

According to the documentation, CHIRP does not currently support the TH-9800.

So my TYT TH-9800 failed today.

I haven't done much testing on it yet, but the symptoms are the same as the failure I had in my Wouxun UV920P (http://rfhead.net/?p=539)
No output power, and the PA stage gets very hot during transmit. Receive is fine.

The radio has *exactly* the same amplifier chain as the wouxuns (pre-driver -> driver (RD07MVS1B) -> final (RD70). The supply voltage on the RD07 is 13.8V (or whatever the supply is), which means any spikes in the supply will pop the FET.

I still have a RD07MVS1B spare from my Wouxun repairs, if I don't get a suitable response from the seller, I may try and replace the FET and fix the supply issue.

Cheers,
Mark VK5QI

I'm interested to see what you do with this to fix it.. A local has one and it lasted a week before it blew up. Draws 11A on TX and makes no measurable power on a SWR meter..

I repaired a Wouxun KG-UV920P for a friend about 6+months ago.

The symptoms were that it drew 10A on tx, both bands, no RF output.

The PA FET got very hot, but it was not faulty, the fault was the driver FET. The circuit of the radio is a proprietary secret, and you have to think carefully about buying these things when this is the case. So without a circuit, I am guessing, but my guess is that the PA bias is such that it draws quite high current without drive.

Wouxun have produced at least three variations on the above model with changes in the driver circuit. In our case, they recommended a further mod to reduce to supply voltage to the driver, and that seems to have been successful. (I wrote the repair up, but VK1OD.net is no longer online. The mod was to take supply for the driver from the 8V regulator.)

I found out later that the owner had operated the radio sitting on his desk on full power. This has almost certainly contributed to the original failure as it denied free flow of air the the heatsink under the radio.

Most of these radios run very hot, and adeqate cooling must contribute to longer life.



Above is a pic of supplementary cooling for my IC2200H which otherwise reaches case temperatures in excess of 75° even though free air movement is unobstructed. The fan is thermostatically controlled, more at http://owenduffy.net/blog/?p=877.

The fashion these days is to produce radios with very high output power in a quite small package, and invariably the cases reaches very high temperatures.

Owen

VK5QI wrote:So my TYT TH-9800 failed today.

I haven't done much testing on it yet, but the symptoms are the same as the failure I had in my Wouxun UV920P (http://rfhead.net/?p=539)
No output power, and the PA stage gets very hot during transmit. Receive is fine.

The radio has *exactly* the same amplifier chain as the wouxuns (pre-driver -> driver (RD07MVS1B) -> final (RD70). The supply voltage on the RD07 is 13.8V (or whatever the supply is), which means any spikes in the supply will pop the FET.

I still have a RD07MVS1B spare from my Wouxun repairs, if I don't get a suitable response from the seller, I may try and replace the FET and fix the supply issue.

Cheers,
Mark VK5QI

Howd you go with this Mark? Have you developed a mod for this, or am I on my own?

Dion
7DB

Hi Guys,
I have a little experience with the Wouxuns, the failures that I saw, were pin diode switches in the Tx OP path. It would seem that they control the TX power with bias, so if the driver fails, it will still draw heaps of DC, with no appreciable RF O/P. I would not be running any of these type of radios on 13.8V, would not go over 12.5V myself, unless the driver fet was supplied with less DC. Overall their performance is not too bad, Rx and Tx, but I think that 'they' try to squeeze too much TX power out of them. Ten to fifteen watts less, on high power would make a far more reliable radio. Oh, and keep the overs short.
My 2 cents worth.

Regards

Peter vk3apw

VK3APW wrote:Hi Guys,
I have a little experience with the Wouxuns, the failures that I saw, were pin diode switches in the Tx OP path. It would seem that they control the TX power with bias, so if the driver fails, it will still draw heaps of DC, with no appreciable RF O/P. I would not be running any of these type of radios on 13.8V, would not go over 12.5V myself, unless the driver fet was supplied with less DC. Overall their performance is not too bad, Rx and Tx, but I think that 'they' try to squeeze too much TX power out of them. Ten to fifteen watts less, on high power would make a far more reliable radio. Oh, and keep the overs short.
My 2 cents worth.

Regards

Peter vk3apw

That's exactly the issues I had with mine. I thought about offloading the radio, but once I get around to doing the mod, I think I'll keep it as, despite the obvious TX issues, they're a pretty decent and quite capable radio. Mine spent a LOT of time mobile around the inner city and the RX absolutely crapped all over Icom and Yaesu rigs I'd run at various other times when it came to handling all the strong signals present in that environment. Not perfect, but a loooong way ahead of the Japanese offerings.

VK5QI wrote:So my TYT TH-9800 failed today.

I haven't done much testing on it yet, but the symptoms are the same as the failure I had in my Wouxun UV920P (http://rfhead.net/?p=539)
No output power, and the PA stage gets very hot during transmit. Receive is fine.

The radio has *exactly* the same amplifier chain as the wouxuns (pre-driver -> driver (RD07MVS1B) -> final (RD70). The supply voltage on the RD07 is 13.8V (or whatever the supply is), which means any spikes in the supply will pop the FET.

I still have a RD07MVS1B spare from my Wouxun repairs, if I don't get a suitable response from the seller, I may try and replace the FET and fix the supply issue.

Cheers,
Mark VK5QI

Any progress Mark on your issue? Did you manage to modify the driver supply?

This sounds very much like a fault I found in an FM broadcast exciter I was asked to repair, the thing doesn't have a brand name on the front of the 1RU unit.
The modulator stage uses a small RF output FET (which gets extremely hot), then the output RF (100mW or so) is fed to a separate PA board with a FET device (RD30HVF) which has died.
I haven't repaired it yet, but same basic symptoms, draws plenty of current, no RF power out.

I can't find a diagram for the thing either, so I might have to build a small DC regulator to supply the driver. When I say it gets hot, probably hot enough to cause dry joints in next to no time, if not unsolder itself.

Is there a common problem amongst Chinese designed RF gear in that they run things at or beyond their design limits?
I won't even go into Chinese 240V wiring...

So I've just received a TH-9800 as a present and I was wondering if anyone had repeater files to share before I go attempting to program them all in !


Ian,,, the link to your band limit file doesn't work any more - do you sill have that to share ?

thanks

Tim

VK2XAX wrote: ↑Thu Jul 04, 2019 2:42 pm Ian,,, the link to your band limit file doesn't work any more - do you sill have that to share ?

Try here

Hopefully it's still compatible.