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Palomar 400 Elite.. had to do it..
- Thread starter CB590
- Start date
Not for nothing but my 63' endfed going as a sloper from say 9' at feedpoint, to like 25' into a tree hooked up to the CB and tuned manually using a manual has no apparent gain than my A99.
Probably because it's and endfed and not a true dipole.
But again I was told 1-2 antennas. I have my endfed and my A99 and even a roll-up for 2/70cm just off the porch..
The post was asking about an amp and here we are talking about antennas, which I addressed.. Sirio or Maco 103/104 or equivalent when I move to NC in 2-3 years..
Audioshockwav, what would you suggest as a good setup, assuming the amp takes the ab1 biasing well? Meaning, if you weren't going to take short cuts, what would you do differently to make these amps perform better? How does instability show on these amps?
Common problem the amp stays keyed after you unkey the radio because it starts self-oscillating.
Some of them you could get away with cutting the Inductors grounding the bias and adding negative feedback across the transistors cleans them up some.
Not taking shortcuts would be like the Magnum or Cobra amps that were built with electronic adjustable bias with thermal tracking and some filtering on the output.
They are what they are, CB amps.
Most like the old gray amps had no bias at all because as long as they worked, the builder spent no time or additional parts to make them better, why?
It cost them more to build and no one cared.
This is why solid state ham amps cost big $$$ and CB amps are relatively cheap, they are properly built with adjustable bias, high SWR shutdown, over drive protection, band pass filtering, overheat protection.
73
Jeff
Some of them you could get away with cutting the Inductors grounding the bias and adding negative feedback across the transistors cleans them up some.
Not taking shortcuts would be like the Magnum or Cobra amps that were built with electronic adjustable bias with thermal tracking and some filtering on the output.
They are what they are, CB amps.
Most like the old gray amps had no bias at all because as long as they worked, the builder spent no time or additional parts to make them better, why?
It cost them more to build and no one cared.
This is why solid state ham amps cost big $$$ and CB amps are relatively cheap, they are properly built with adjustable bias, high SWR shutdown, over drive protection, band pass filtering, overheat protection.
73
Jeff
An amplifier that's not built to be stable may appear to behave itself when operated in class C. The Gray 300 is a good example. This is in part because of the "threshold" behavior of a class-C amplifier. Until the drive wattage reaches that threshold, the RF transistors remain turned off. As soon as the drive level exceeds the threshold level, it amplifies. This will make it seem less sensitive to small amounts of positive feedback in the system. If it's not enough to 'turn on' the RF transistors, the amplifier will appear to work more or less okay on AM or FM and unkey itself every time.
As soon as bias is added, the transistors are now sensitive to the tiniest bit of drive. And if that drive is your unwanted positive feedback, adding bias will cause that amplifier to oscillate its kiester off, compared to how it behaved set up in class C without bias.
Adding bias only works in the amplifier was already designed to be stable in the first place.
73
As soon as bias is added, the transistors are now sensitive to the tiniest bit of drive. And if that drive is your unwanted positive feedback, adding bias will cause that amplifier to oscillate its kiester off, compared to how it behaved set up in class C without bias.
Adding bias only works in the amplifier was already designed to be stable in the first place.
73