can transmit on any frequency from 18mhz to 1.3ghz, 5w output, has no harmonic filter, something for someone to put in a wall maybe (another thread here has talked about been haunted by the 2nd harmonic)

Interesting but very dangerous. It almost seems like the Chinese want to flood us with spurious emissions in the West. If you got caught using that in China you probably end up in the back of a van and not seen for 5 years, unless I am totally wrong of course.

I've got a couple of "Baofeng" handhelds that will transmit on any frequency I cchoose from 125 MHz to 540 MHz (or more). They're designed for dual-band use (2m and 70cm) and have very low harmonics (-72dBc on 70cm and better on 2m) and don't have any spur outputs at all. I tried one in the 174 MHz radio microphone band, and its performance was really good, but not quite as well filtered as inside the amateur bands.

If you're buying radio gear from China, do your research! Some of the better known gear is very good, but a lot of the rest is rubbish!

it did make me wonder if this could produce wideband mod, weather it was simliar to an rf generator, some of them are clean, hard to get audio in, I do have max2870, they are quite clean in the fm band, the 5.8dbm can go straight into alittle 2.5w amplifier, the audio can be a pain, I use an op amp audio buffer, theres just the harmonis to filter out is the way it should be.
This does already have an amp, an audio input, I suppose you could trace the audio input back, see if it was capable of wideband mod, they are not meant for this but I suppose niether is a signal generator, just a passing though. You’d have something that looked like a walkie talkie if it worked, it could be put a box I suppose.
Anyway the max2870, it could be used for ham stuff, the frequency range is from 35-6ghz, its not been checked for spurious at other frequencies, it could be used as a microphone at 174 very easily, as an stl link too. I listened to the audio on a scanner without the amplifier, I could hear it up to the highest frequency the scanner could go to, it could go to a much higher frequency.

Generally, it's just easier to build a conventional rig!

The exciter we commonly use has a half frequency dual-gate FET VCO, followed by a gain-controlled DGFET buffer, then a balanced doubler to the output frequency. There's a further buffer, then a broadband amplifier that takes it up to about 3 Watts. There's a level sensor "sniffing" the 3W signal, and adjusting the gain of the buffer stage, so that the power output can be set accurately, and the same power is developed on any Band II frequency without adjustment.

The PLL is one of three types - the simple diode-programmed CMOS version, one based on the TSA5511 and a PIC, and another one using an LMX-series PLL IC and another PIC. The LMX version has the advantage that the PIC also provides (fixed) RDS if required.

The double-sided PCB that houses these little devices is designed to fit neatly inside a standard "Eddystone" diecast box, with BNC connectors for modulation and RF out, and feedthrough capacitors for the supply and monitoring points. They're cheap as chips, entirely clean, and can be machine-manufactured. There are no non-standard components in them!

Maybe harder to build a conventional rig though!, the thing that worries me, there maybe pcbs out there but telling whether its working at frequency or at half frequency is impossible. I got a tx a while ago think was from greece it used something like a tsa5511, it was a few watts, maybe about 6, it buzzed when the rf stage was going, something i’ve not noticed in other txers. I think it was at frequency, may of been the loop filter too, i’m not expert on these things for sure. It also had an unstable rf ampliflier too, when changed from a low frequency to a high frequency, the rf would jump up and down, they were availble built up, the way to go if you want everyone to know you’ve got a transmitter too, it comes labeled with that on it.

I do see someone selling pcb on its own for a pll, it is quite expensive for just the pcb, with no components provided too, dosen’t seem there is much to it, could be good thing as not many components are needed to get it working, there maybe some programing involved, the oscilator type is also unknown. I might have ago see if its possible to make one of these things work I don’t know.

Not so long ago someone was selling off the rf pll generators with the oled display for the same price as the pcb, does seem over priced. (but the only way to get a pll) The rf generator is not meant for high power someone 300w transmitter but for a few watts it is very good, no buzzing either, easy to set frequency too, trying to build something yourself you'll also have to put things like out of lock power down circuits. Noone in the uk is selling built up pll’s, so I don’t think is easier to build one, there is only one pcb for a pll availble from the uk, were the quailty of it, weather or not you’d get it working is uncertain.