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is this worth building
- Thread starter 1iwilly
- Start date
Only if you lay it out to keep the input and output sides separated. If the radio you're using has sideband, it should have a place to unplug the final transistor for measuring final current. Pull it out and you'll now have a far weaker receive signal from the radio. Pull the bias-test jumper from the driver as well, and you'll have a really weak signal to work with. There won't be any modulation with both bias-test jumpers pulled out, just a carrier.
73
73
Iiwilly -
I have used one of these things for decades. Not what you would call "hi-tech" test gear, but does the job well for what it is. I always feed a prerecorded audio track into the test radio. Just listening, while not hearing yourself speak, is more effective.
- 399
I have used one of these things for decades. Not what you would call "hi-tech" test gear, but does the job well for what it is. I always feed a prerecorded audio track into the test radio. Just listening, while not hearing yourself speak, is more effective.
- 399
i have another radio on a dummy load that i use to monitor modulation i must have the wrong headphones I'm just looking to tell when the mod is low and then high after a tune-up
5 Miles at CB Frequencies is 43 dB attenuation. The diagram is all most correct, the series resistor needs to approx 3.1 K
Jay in the Grate Mojave Desert
Jay in the Grate Mojave Desert
Well I'll put it this way.....
With a few calculations... and a bell and whistle or 3 added....
As long as you check with a freq counter.....
This could be a fair "poor man's RF generator for receive alignments and such...
It would never be a lab instrument.... but hey.....
"The warrior uses what is at hand"!!!!!!!!
I would think of adding a rotary switch.... OR a pair of screw down banana jacks...
so I could switch dropping resistors.....calculate the dB attenuation.....
ad you could make your bench radio drop to any level you need.
Again, not bench quality.... but if "you don't tell.... I won't tell!!!!"
Build a little integrated circuit audio oscillator to plug into the mic jack on the bench radio...and now you AT LEAST have AM modulation.....
With a few calculations... and a bell and whistle or 3 added....
As long as you check with a freq counter.....
This could be a fair "poor man's RF generator for receive alignments and such...
It would never be a lab instrument.... but hey.....
"The warrior uses what is at hand"!!!!!!!!
I would think of adding a rotary switch.... OR a pair of screw down banana jacks...
so I could switch dropping resistors.....calculate the dB attenuation.....
ad you could make your bench radio drop to any level you need.
Again, not bench quality.... but if "you don't tell.... I won't tell!!!!"
Build a little integrated circuit audio oscillator to plug into the mic jack on the bench radio...and now you AT LEAST have AM modulation.....