04-02-2021, 08:57 PM
One can inject RF unmodulated at a given frequency get a tone as it heterodynes with some signal locally. Change the frequency of the generator (again, no modulation) and have what appears to be no signal..
I have done it then discovered the generator was not set for modulation.
-----------------------------------------------------------------------------------------------
As for inductive coupling, I use that most of the time to avoid lashing up an antenna matching network for the generator. I leave what ever antenna is in my lab connected, usually 10-15 feet of clip leads and sometimes ground connected. Yep, I get heterodynes with the local stations but they are very weak, the "locals" are 100 miles away at 550 and 1500. My advantage to link coupling is the antenna is still properly matched and I have isolation for the AC-DC set, one more, I am not likely to drop a hot lead from the generator onto the B+ and taking out the generator attenuator.
The link also provides a convenient source of local oscillator if I suspect the oscillator is not working or cutting out...
When I serviced for a local shop (I was MA licensed Radio/TV technician) we did stuff that would seem unusual but it was fast and conclusive. Get the set analyzed, fixed and be writing the bill in 20 minutes. Back into the truck and across town for the next job... chas
I have done it then discovered the generator was not set for modulation.
-----------------------------------------------------------------------------------------------
As for inductive coupling, I use that most of the time to avoid lashing up an antenna matching network for the generator. I leave what ever antenna is in my lab connected, usually 10-15 feet of clip leads and sometimes ground connected. Yep, I get heterodynes with the local stations but they are very weak, the "locals" are 100 miles away at 550 and 1500. My advantage to link coupling is the antenna is still properly matched and I have isolation for the AC-DC set, one more, I am not likely to drop a hot lead from the generator onto the B+ and taking out the generator attenuator.
The link also provides a convenient source of local oscillator if I suspect the oscillator is not working or cutting out...
When I serviced for a local shop (I was MA licensed Radio/TV technician) we did stuff that would seem unusual but it was fast and conclusive. Get the set analyzed, fixed and be writing the bill in 20 minutes. Back into the truck and across town for the next job... chas
Pliny the younger
“nihil novum nihil varium nihil quod non semel spectasse sufficiat”
