I tried modifying the input tuning to be similar to the one in the PDF, but after a lot of tries I ended up with something similar to what I had originally. I have an 80pf trimmer directly on input, then I have another 80pf going to ground along with 2x 180pf fixed caps and a single turn of about 4mm diameter. This gave me < 1.5 SWR on the input at 87.9MHz (which is the frequency I want).

Anyway, it appears that there is a problem with oscillations. When I input about a watt, I get the same amount out. I noticed when I turn off the exciter, the output stays 1W, so I looked on a spectrum analyser and it looks like oscillations (never seen that before), but it basically just looked like a mess of spurs everywhere.

Maybe my layout is flawed. I might post some pictures later.

Also, if any of you want to mess with it I'd be willing to send it to you.

Chinese RD70HVF1 from ebay ???

RF-Head wrote:Chinese RD70HVF1 from ebay ???

Quite possible. Someone gave me a BLF244 to test the other day, it was packaged in the usual Chinese silver bag with yellow ESD sticker on the front. I tried it in circuit and it didn't work at all, it did about 4W and the suddenly drew loads of current at a certain bias point. I took it out of circuit and tested on a curve tracer and found it was a bipolar, not even a FET! It just shows these guys will remark and old shit they find but what amazes me is that they can refurbish the legs, paint them gold and make the device look brand new again.

OgreVorbis wrote:
Also, if any of you want to mess with it I'd be willing to send it to you.

I can give you a hand if you PM me, the only thing is I probably won't have time to have a good look at this for a couple of weeks. If I have some success I'll post the finished design on here for others to try.

I sent you a PM.

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