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Output is 2sc1971 and it gives 5-8 W. Input is about 0,3 to 1 W max. Driver stage is BFR96 is about 0,3W, so that is minimum of input power for output transistor...
OH, come on, its not that obvious. That pad that you see, on the front side of PCB, is not in use. Soldering pad is on the back and there are the connections. Do You see that this pad leads to nowhere? :)
Hello. Me again after few days. As I said before, I have results after finishing casing for PCB. Results are bad, almost the same like without the enclosure so I am worried and disappointed now.
Quick explanation of the problem: Device loosing lock when power is increased at about 1W and more...
I dont understand this thing with pulling, maybe you are right, but let me explain one thing. First thing I built on board was VCO, J310 fet with its two varicaps. Then I applied about 7 V to varactor ( half of the value of the voltage of the entire unit, which is 13,8 V). Then I did some...
Maybe those printed inductors made from copper are making interference. Now I remember that I saw the photo of transmitter like this that have shielding between those printed coils and rest of unit.
This was not my first one-side pcb of this transmitter. Only difference is that this one on the photo is no-tune version. Other difference is it has printed coils on board instead of wire-coils inductors.
Also, we all know that double side PCB is harder to make than one-sided. Also, I love to...
Hello. No, it is not the case. I don't use that part of the chip at all. I just use it as the stereo encoder. Today, ba1404 was even out of its socket when I did some testing, and problem was the same, so we are now sure that its not making troubles.
Hello guys, thanks for replies. Yes, most probably the problem is unwanted RF somewhere in the PLL loop. I have built few of these transmitters (not no-tune versions like this one on image) and this is the first time to deal with this kind of problem, but I guess that is the RF magic, right...
Hi there. I registered today and this is my first thread here. I see that you guys do the help all the time, so my guess is that I will get some help too.
I recently completed fm transmitter ( no tune RDVV ) and I have problem because it is losing lock when power is more than about 0,5 W...
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