Hi everyone, it's been a whole since I posted. I have a couple questions about my base setup aND these mosfets everyone's using now.
I'm using a magnum 257hp threw about 60 feet of very low loss thick coax I bought from a ham site (can't remember) into my sirio gain master mounted almost to the peak of the eve of my one story house. I'd like to get higher but this is what I got for now. It's working pretty well, I've got everything tuned nicely where I'm not running the hell out of the radio. It's doing typically 10-12 bird carrier AM and 60 to 70 ssb. I mounted fans on the rfx unit to keep it cool, and everything is hooked to a scope so I can obsess over my modulation. Lol
I notice with my setup in the lower bands A -C 25_26 mhz my bird is showing more output than the higher h-J bands 28 mhz . I'm trying to figure out how I can smooth this out. The difference isn't huge but I'd say 5 or 7 watts rms.
Is this due to antenna length and things of this nature or is it harmonics the bird is reading on the 30 mhz slug on the lower bands it can't see on the higher? Or is this due to high freq capacitance in the mosfets? I know that in bjt transistors when you get close to the cut off freq the gain can significantly drop due to collector-base and emitter - base capacitance. I'm not sure how this works in mosfets though?
I did read about the miller effect some but a lil advise that's more specific to cb, export radio finals would be helpful. I have a pretty general understanding for electronics. Not pro, but enough to tinker and do some damage. Lol. Thanks
I'm using a magnum 257hp threw about 60 feet of very low loss thick coax I bought from a ham site (can't remember) into my sirio gain master mounted almost to the peak of the eve of my one story house. I'd like to get higher but this is what I got for now. It's working pretty well, I've got everything tuned nicely where I'm not running the hell out of the radio. It's doing typically 10-12 bird carrier AM and 60 to 70 ssb. I mounted fans on the rfx unit to keep it cool, and everything is hooked to a scope so I can obsess over my modulation. Lol
I notice with my setup in the lower bands A -C 25_26 mhz my bird is showing more output than the higher h-J bands 28 mhz . I'm trying to figure out how I can smooth this out. The difference isn't huge but I'd say 5 or 7 watts rms.
Is this due to antenna length and things of this nature or is it harmonics the bird is reading on the 30 mhz slug on the lower bands it can't see on the higher? Or is this due to high freq capacitance in the mosfets? I know that in bjt transistors when you get close to the cut off freq the gain can significantly drop due to collector-base and emitter - base capacitance. I'm not sure how this works in mosfets though?
I did read about the miller effect some but a lil advise that's more specific to cb, export radio finals would be helpful. I have a pretty general understanding for electronics. Not pro, but enough to tinker and do some damage. Lol. Thanks