Yes! I simulated that chip in ltspice, and the highest value of the resistor to make a relay work is 1k. I got about 100mA thru ptt with 1k.? Plenty for a relay.? Now, the problem is with lowering the value. The bus that R81 is getting the voltage from might be affected, and other block circuits might be affected if too much current is drawn. So I thin think 910 to 1000 ohms should do.?

You mean R81 then that connects the LK1801S input to the PTT signal. This means that if you don't change this resistor it will not turn on the Darlingtons no matter what...
Brgds, Edouard F4EXB.?

The design is wrong, and China manufacturer knows it. It need a resistor value changed from 4.7k to 560-1000 ohms.?

You will not damage anything but it simply won't work. The XPA125B needs to sense less than 0.1V to switch to Tx and it seems the darlington mount on the Q900 side cannot get that low when turned on. One would need an intermediate relay which is a pain.

Good idea, Dick. But I think it would cost money. I'll investigate.

I hope to get back in control here "soon". I had extensive additions planned until March 9 when i first started hearing actual info from the WhatsApp group. I have been watching, but have had a number of time consuming matters.

It was my idea to keep this as a place for "average hams" who may have info to contribute or who had questions not as technical as what has passed since then on the WhatsApp group.?

I had thought this should not be sponsored nor controlled by the manufacturer. But I didn't want just a place to flame and complain.

I plan to spend a little time here tomorrow or Monday. Suggestions like yours are welcome.

George

Probably sell it. ?But I am using it successfully for in satellite operations using HRD for frequency control. ?The split antenna situation is actually a benefit as I have an LNA on the mast for 432 that feeds the receiver and I don’t need any fancy switching. ?And the QR 20 once I repair it I will probably sell. ?

Just so you know, below is the link to the What'sApp group where the purchasers who are engineer-types are discussing the radio You can see that there are a lot of unhappy people over this radio:

So are you going to buy another radio to be able to use VHF/UHF properly? What will you do? with the old radio?
--
Bob, KL7EAL Los Angeles

开云体育

Totally agreed.?

I’d put it more like it does 90 percent of what it is supposed
to do. ?I use mine a lot.

I would ask GOUHETEC why they don't just offer an upgrade to the version 3, but they never answer questions like that. Why spend all that money for a function that should have been there in the first place? Plus, what to do with the old radio? Junk it, as it's useless for half it's features or more.
--
Bob, KL7EAL Los Angeles

Hi Admin,

Can we put in a files section? so we can find information on versions, tests, etc.. more easily..?

Im asking as it is a PITB to find stuff in the whatsapp group, and if you are new there, you can't see history..?

I have seen a WiKi and maybe that would be something to use too..?

Would be nice of Guohetec to sponsor.. :-D

73,
Dick

A new V4 Q900 is being released. ?It adds single antenna tx/rx on V/U via the sma connector, and hf/6m through the other connector. ?Also higher audio out for headphones and the 70 MHz band. ?

Also DMR fixed.

If anyone buys this and tests the functionality it would be nice to see what the results are. ?I’m curious as to whether dmr will work through hotspots and repeaters.

Yes, that was the mystery in the first place. The microphone that comes with the radio is a speaker mic and so there is audio going to the speaker in it.? It takes the audio from the earphone plug, bypassing that!? So anything you can hear from that plug is so tiny that it's not worth listening to. And the audio in the speaker-mic is so low as well, it's useless in any kind of noisy space.

Why this is not explained in the manual or elsewhere, I don't know. I even? opened up the radio twice? trying to find out what was wrong, but accidentally left the mic off once, and bang! Full audio from the earphone plug, suitable for amplification into a full room-sound quality result!
--
Bob, KL7EAL Los Angeles

Just wondering if you get the same from plugging it into the headphone jack socket included with the radio.

73

I? think? I'll have to try that for now, for my 70? foot length wire got knocked down in the wind last night!
--
Bob, KL7EAL Los Angeles

To clarify I had a bnc to binding post adapter, and equal lengths of speaker wire attached to both hot and ground. ?So essentially a dipole.

Really? Just a speaker wire? I haven't managed to match my G90 with antenna tuning but it certainly does have a working antenna tuner!
--
Bob, KL7EAL Los Angeles

I? hate the scratchy speaker on this radio but the audio out from the speaker jack seemed to be very low, having to turn it all the way? up in the audio settings to get anything amplifiable. Then tonight I? noticed that the headphone audio was perfectly fine if I unplugged the microphone that came with the radio! What? So then I was about to open up the microphone and disconnect the speaker in it, (it's a speaker-mic), when I noticed a tiny hole next to the wire going in! A headphone jack!

So I plugged my little Anker blue-tooth wired speaker plug into that and Wahoo! Beautiful full-quality sound! So the speaker-mic was taking all the audio from the headphone output, and I'll probably disconnect the wire inside but for now I can listen to this little wonder like it had a large sound-system hooked up to it!

After years of listening to SSB on older radios, it is a pleasure to hear SSB on these new radios, as you can set the bass in the audio settings to your taste. Many people have a pleasant bass component to their voice when in conversational mode on local 40-80 meter nets, so this is a big plus.

That, plus the DSP settings and the radio begins to sound like the people are in the room with you!
--
Bob, KL7EAL Los Angeles