"P. Venkman" wrote in message
om...
"Highland Ham" wrote in message
...
Here's an idea. How about talking to the senior radio technician on
the
military base? Just maybe he/she would have the answer.
================
Or borrow a handheld scanning receiver. It could well be that a nearby
transmitted signal ,not necessarily on or near 'your ' transmitted
frequency
affect the RC receiver (which probably has limited immunity in respect
of
strong harmonics/mixing sigs.)

Frank GM0CSZ / KN6WH

I appreciate the replies, but the problem is NOT with the receiver,
it's with the transmitter.

I admit this was more or less the response I expected, but I really
hoped someone would say 'oh, I had the exact same problem and designed
and built a filter for my transmitter that fixed everything, and I'd
be happy to show you how to do the same'. But thanks for the replies,
I do appreciate it.

Look, if the transmitter is "synthesized" i.e. not crystal bound, and it is
suffering the problem only near the Military base, then it is pretty obvious
that the transmitter is being overwhelmed by a stronger signal. IT CAN AND
DOES HAPPEN! The minute signal of your transmitter milliwatts to a watt or
so is most likely being swamped out by the mega watts they are using or the
mixing of the signals is doing it. Either use a crystal controlled
transmitter there, or quit flying there! They're not going to shut down for
you to fly your model plane. You claim that is the only place it happens....
Sooooooo! Maybe no one else flys in RF bombarded fields to have experienced
the same problem that you're looking for the answers to. The answer is
obvious. Crystal controlled or stop flying there.

Lou

In case anyone cares I have an update on this. I was able to get a
crystal controlled RF module for the transmitter and that took care of
the problem. It's definitely the synth RF module that's experiencing
the interference.

I'm still interested in findind a way to deal with this aside from
just not using the synth module at that site. Now that I've more or
less isolated the problem, is there anything I can try? I did make an
attempt at sheilding just the RF module with no luck, but are there
other options?

Thanks.

In case anyone cares I have an update on this. I was able to get a
crystal controlled RF module for the transmitter and that took care of
the problem. It's definitely the synth RF module that's experiencing
the interference.

I'm still interested in findind a way to deal with this aside from
just not using the synth module at that site. Now that I've more or
less isolated the problem, is there anything I can try? I did make an
attempt at sheilding just the RF module with no luck, but are there
other options?

Thanks.

"P. Venkman" wrote in message
om...

I'm still interested in findind a way to deal with this aside from
just not using the synth module at that site. Now that I've more or
less isolated the problem, is there anything I can try? I did make an
attempt at sheilding just the RF module with no luck, but are there
other options?

As long as it's at the transmitter, you could try a bandpass filter. Chances
are the interference is coming from outside the RC band. There are programs
available for free that will give you the numbers you need. I use one called
AADE Filter Design from AADE.com . Ask if you need info on making the
inductors etc.

"PM"

"P. Venkman" wrote in message
om...

I'm still interested in findind a way to deal with this aside from
just not using the synth module at that site. Now that I've more or
less isolated the problem, is there anything I can try? I did make an
attempt at sheilding just the RF module with no luck, but are there
other options?

As long as it's at the transmitter, you could try a bandpass filter. Chances
are the interference is coming from outside the RC band. There are programs
available for free that will give you the numbers you need. I use one called
AADE Filter Design from AADE.com . Ask if you need info on making the
inductors etc.

"PM"

"Paul_Morphy" wrote in message ...
"P. Venkman" wrote in message
om...

I'm still interested in findind a way to deal with this aside from
just not using the synth module at that site. Now that I've more or
less isolated the problem, is there anything I can try? I did make an
attempt at sheilding just the RF module with no luck, but are there
other options?

As long as it's at the transmitter, you could try a bandpass filter. Chances
are the interference is coming from outside the RC band. There are programs
available for free that will give you the numbers you need. I use one called
AADE Filter Design from AADE.com . Ask if you need info on making the
inductors etc.

"PM"

That's very useful, thanks! I downloaded the program and think I
understand it well enough to plug in the numbers. I do have one big
question though. How do I measure the impedance? I've got a basic
VOM but that's it as far as test equipment, and my knowledge of things
electronic is pretty basic.

"Paul_Morphy" wrote in message ...
"P. Venkman" wrote in message
om...

I'm still interested in findind a way to deal with this aside from
just not using the synth module at that site. Now that I've more or
less isolated the problem, is there anything I can try? I did make an
attempt at sheilding just the RF module with no luck, but are there
other options?

As long as it's at the transmitter, you could try a bandpass filter. Chances
are the interference is coming from outside the RC band. There are programs
available for free that will give you the numbers you need. I use one called
AADE Filter Design from AADE.com . Ask if you need info on making the
inductors etc.

"PM"

That's very useful, thanks! I downloaded the program and think I
understand it well enough to plug in the numbers. I do have one big
question though. How do I measure the impedance? I've got a basic
VOM but that's it as far as test equipment, and my knowledge of things
electronic is pretty basic.

"P. Venkman" wrote in message
om...

That's very useful, thanks! I downloaded the program and think I
understand it well enough to plug in the numbers. I do have one big
question though. How do I measure the impedance? I've got a basic
VOM but that's it as far as test equipment, and my knowledge of things
electronic is pretty basic.

Oh, yeah, I didn't consider that your antenna is not 50-ohms. How long is
the antenna, and what frequency band are you using? 72 MHz? When it comes to
calculating what your antenna looks like impedance-wise, there are others
here more knowledgeable than me and I hope they jump in! I wonder how well
shielded the transmitter is, also. If not well shielded the interference
could just get in directly and the BP filter wouldn't help. There are
devices that allow you to measure an antenna's impedance, but they cost
about what your transmitter cost.

"PM"

"P. Venkman" wrote in message
om...

That's very useful, thanks! I downloaded the program and think I
understand it well enough to plug in the numbers. I do have one big
question though. How do I measure the impedance? I've got a basic
VOM but that's it as far as test equipment, and my knowledge of things
electronic is pretty basic.

Oh, yeah, I didn't consider that your antenna is not 50-ohms. How long is
the antenna, and what frequency band are you using? 72 MHz? When it comes to
calculating what your antenna looks like impedance-wise, there are others
here more knowledgeable than me and I hope they jump in! I wonder how well
shielded the transmitter is, also. If not well shielded the interference
could just get in directly and the BP filter wouldn't help. There are
devices that allow you to measure an antenna's impedance, but they cost
about what your transmitter cost.

"PM"