Has anyone used this Turkish driver board?

[MiXiN]

I bought an Amplifier from this guy a while ago, but still haven't got around to fitting the Transistor and using it.
His gear is ridiculously cheap - and I'm not sure how he makes any profit when eBay fees, PayPal charges, and International postage is taken into consideration.
Anyhow, here's the board I'm talking about - http://www.ebay.com/itm/401073844493?ru ... 26_rdc%3D1

Are they clean on the output, does it do the said power, etc'?

[teckniqs]

Got one and it seems to work OK but won't work without the screen attached and mine only gave out 70mW. Changed the 2055 to a 2538 and now it's giving about 300mW.

[MiXiN]

I just zoomed in on the image on this one, and it looks like it's using a 2sc2053 which is meant to be good for 150mW.

Is the audio any good?

Next time I see one pop up I'll buy one. £20 is a steal.

[teckniqs]

Sorry I meant to type 2053, yeah it's a 150mW device but with 12v at approx 88MHz it was no more than 70mW. Audio was fine just like a normal driver and MPX ready. You will see why it's so cheap but still good value!

[shuffy]

I don't like the look of it layout-wise, but that's just me basing it on the pictures - I haven't tried one. It's unlikely to take off at 70mW, but more RF kicking around could be a different matter. Assuming it's clean, I think the tradeoff would be, the price and inconvenience of potentially building an extra stage to drive whatever PA you're intending to use with it versus the cost of a more powerful exciter. This might drive an RD06HVF1 stage to a couple of Watts out if you're lucky? Anyway can't complain for the price.

[Analyser]

I bought one of these drivers a month or so ago and am going to do a proper review and post it on here at some point. My thoughts on this driver, summed up until I get some time;

Good points.
1. It's cheap.
2. Broadband frequency tuning across the band.
3. Nice LCD if you want to make a project from it.

Bad points.
1. It only does about 100mW and the output transistor gets extremely hot so will fail pretty quickly. I couldn't keep my fingers on it for more than a few seconds. Power also varied from about 70mW to 110mW across the band.

2. Audio response dropped off below about 50-60Hz due to poor PLL filter design so not really hi-fi sound and will also degrade stereo separation.

3. Audio level varied massively across the band, I stuck a 1KHz tone in to the audio input to generate 75KHz deviation at 98MHz, the level was around 50KHz at 88MHz and 120KHz at 108MHz. This means you'd manually have to set the audio level for every frequency change.

4. Fairly poor spurious and phase-noise performance. Spurious close the carrier was about -60dBc, so similar to a Dawson driver board. Phase noise pretty shite but I can't remember the figures off hand.

5. General PCB layout could give rise to sprogging if used with a high power amp. Agree with Shuffy on this one. Careful checking and shielding might be needed when used as part of a bigger project.

To sum up; nice to play with and good for the money but decent broadcast quality- no.

[MiXiN]

Nice summary there, Analyser.

When I next see one of these listed I'll take a punt, throw a best offer in, and play around with the driver and final Transistor with a view to cranking up the power when it arrives.

[MiXiN]

My driver board arrived today, and 2 of the Transistors get extremely hot - the 2053 final, and the TO126 BD139 just above the 7805 regulator. As I had some heatsinks, I fitted one to the final. I'll buy one for the other.

On the bottom right hand side of the board there's a red LED. Does anyone know what purpose it's meant to serve as it's not lighting for me.

Also, I seem to recall someone posting the board layout and schematic of this driver a little while ago but I can't find it. Can anyone link me to it please?

Sent from my SM-G900F using Tapatalk

[yellowbeard]

the original ebay listing had this image:

http://www.iol.ie/~yellowbeard/s1600.jpg
The layout is slightly different but the LED in the ebay image says PLL. Good luck and let us know how it goes!

[teckniqs]

Well spotted

[MiXiN]

OK, after closer inspection, the LED on mine is to show that there's RF output. I altered the variable resistor and the LED started to light from 3/4 the way upto the highest power.

This one of mine does around 50mW at the lowest setting on the VR, and around 200mW at the highest - but at the highest level the heatsink on the final gets pretty hot.

All in all for just over £20 I can't moan.

[teckniqs]

Finally got around to testing the RDVV I bought from this seller the other day, doesn't work at all. Does nothing.
When it arrived it had the screen plugged in so I removed it before testing because the other RDVV's I've got work without it but I'm wondering if because I removed it that's why it won't work? Unfortunately the screen was connected via individual plugs for each pin and not the proper large connector. I have no idea where they go because most of them had fallen out before I tried it.

[MiXiN]

That's shite news Teckniqs. Hopefully someone will be able to advise on where to connect the individual plugs.

Does anyone know what the brown trimmer capacitor is for on the upper right hand corner, and also what function the BD139 Transistor serves?

That BD139 (upper right to the 7805 regulator) gets really hot when the power to the final is turned down, but runs cool when the final is running at its highest power.

I'm guessing it's acting as some sort of series pass Transistor, but reverse engineering isn't my forte and I can't source the schematic for this driver anywhere.

[teckniqs]

Yeah not great but I'm sure it won't be too hard to get sorted out.

That brown trimmer looks like a 60pF and it's on the RF output stage so it will be some kind of matching adjustment I presume.

I think the BD139 is working as an adjustable regulator for the adjustable power RF stage, there's one on the RDVV's too.

[MiXiN]

Yeah not great but I'm sure it won't be too hard to get sorted out.

That brown trimmer looks like a 60pF and it's on the RF output stage so it will be some kind of matching adjustment I presume.

I think the BD139 is working as an adjustable regulator for the adjustable power RF stage, there's one on the RDVV's too.

Nice one mate.

I've ordered an Heatsink for that BD139 but until it arrives I don't know if there's enough clearance on the board to fit it.

Good luck with your RDVV - I'm sure someone will chime in on a fix soon.