On one of the well known auction sites I've found a VHF Transmitter using a 2N3866 as the final Transistor that claims to do 1W output with a 15V supply.
Now, looking at datasheets for this Transistor suggests it will only provide 1W at 28v. I'm not great at reading datasheets, but am I missing something?
In a nutshell, I'm trying to work out what this Transistor will "realistically" produce at a 15V supply? Is the seller exaggerating claims?
Am I allowed to post a link to a website in which people who have used them state they've not obtained much more than 0.5W out of them at a similar voltage, or are links to other forums disallowed?
The link I refer to is Pirate radio based, and many of the members assemble, use, and sell Transmitters, Amplifiers, etc', so it all gets very confusing.
Am I allowed to post a link to a website in which people who have used them state they've not obtained much more than 0.5W out of them at a similar voltage, or are links to other forums disallowed?
The link I refer to is Pirate radio based, and many of the members assemble, use, and sell Transmitters, Amplifiers, etc', so it all gets very confusing.
Probably best not to post links to sites of a dubious and illegal nature
The power output rather depends on how you care to measure it, commonly (back in the day) it was simply by measuring the DC power to the output stage - and this value was what your licence conditions referred to.
As I recall?, my amateur radio licence allowed 150W DC input (for FM or CW) and 400PEP for SSB.
Like I mentioned earlier, power output is normally measured as the DC input to the final PA stage, however efficiency is nothing like as bad as the 30% claimed by Colin - who seems to know little about electronics or radio.
Nowadays RF power is typically observed via direct measurement (via a metered directional coupler followed by correct termination) --- In point of fact, compliance with (US) regulations stipulates direct measurement...
FWIW: Re: the 2N3866 and similar devices (e.g. 2n3553, 2n6255, M9466, M9657, etc...) Maximum rated RF output is readily obtained at collector EMFs of even 13.8V --- and efficiently so in 'class C' operation... --- I apologize that I've not had occasion to make a quantitative assessment of efficiency, howbeit, inasmuch as a small 'top hat' heatsink proves quite adequate up to 3W (RF out) it can't be too bad! --- That said - I do not 'endorse' operation of devices beyond their absolute maximum specifications and accept no responsibility for consequences thereof!
On one of the well known auction sites I've found a VHF Transmitter using a 2N3866 as the final Transistor that claims to do 1W output with a 15V supply.
Now, looking at datasheets for this Transistor suggests it will only provide 1W at 28v. I'm not great at reading datasheets, but am I missing something?
In a nutshell, I'm trying to work out what this Transistor will "realistically" produce at a 15V supply? Is the seller exaggerating claims?
This link may be of interest to you. One thing to be wary of is that unless your 2N3866 comes from a reliable supplier you are liable to get a rip-off device which will not meet the device specification by a wide margin.
The input power must be more than the output power. The circuit in the video uses 12V at 130mA which is only 1.56W. 16V at 300mA was mentioned which is 4.8W but it does not say which output transistor was used.