So it has been over a month since I have heard from the FAA. You may recall they read me my rights, told me I could be violated for each and every flight, and contacted me roughly twice a week for a month..
..... Not sure what you mean about a quarter wave stub, since my antennae are all 1/4 wave. But willing to try . . .
His point is well taken, although I think I would have phrased it differently. I get to the airport and am usually so full of joy that I forget little easy tasks like this.
Today I took the J4 up - it has the newest and noisiest 200 - and with the cooperation of the tower folk, spent 15 minutes on 125.675. Nada. Not a peep. Silent.
While that may not be definitive (I could have picked the exact 15 minutes where no simultaneous transmissions occurred), I note that twice on the climbout (125.7) and once on the descent I had approach control interference.
Only thing I can figure is that there is some non-linear anomaly somewhere. Not sure what you mean about a quarter wave stub, since my antennae are all 1/4 wave. But willing to try . . .
so do you cut the coax, then trim looking at a signal generator?
So you are thinking that the mixing is going on inside the RF section of our receiver, and filtering out the UHF will prevent the mixing. Is it possible that the difference signal exists before it hits our antenna? If so, would it do any good to filter out the higher frequency?
Web, I have seen TSO'd wheels with 1936 dates on them with an airframe cert date of 1940...so I think that only some things were TSO's back then like wheelsTSO's were not invented yet when CAR 3 was written. No requirement for it in any of the CAR's. I've never seen it mentioned in Part 135 either but guys have let stuff like that get written into their ops specs. Then you don't have any choice.
Web
Web, I have seen TSO'd wheels with 1936 dates on them with an airframe cert date of 1940...so I think that only some things were TSO's back then like wheels
I'd rough cut it long then sweep it with a spectrum analyzer tracking generator. That will produce a plot of the notch which shows the center frequency and bandwidth.
It is not quite as painful as that. Other than the 125.7 interference, these are the best radios I have ever worked with, the best displays, the best memory circuits, easiest to install, and by an order of magnitude the best intercom.
Yes, I would love to try the stub.