Tim Wescott wrote in message ...
P. Venkman wrote:

Tim Wescott wrote in message ...

P. Venkman wrote:


Tim Wescott wrote in message ...


P. Venkman wrote:
SNIP

I've tried the transmitter with 5 different receivers (4 different
brands) on 5 different frequencies, all with the exact same problem.

At one point I had two different receivers (different brands) on the
same frequency turned on, and when they glitched they both glitched in
exactly the same way (rudder went hard right on both models, for
example). This isn't proof, but in general you wouldn't expect two
receivers to glitch in exactly the same way if the problem is
interference at the receiver.

If two receivers are receiving exactly the same interference at exactly
the same time they may glitch the same way.

Possible; however, they were different brands and different circuits,
and it's less likely that some random interference would cause them to
act the exact same way. The same brand wouldn't surprise me.


Since it's a synthesized module and should be easy to do, have you tried
it on a different frequency (with appropriate RX, of course)? Obviously
something screwy is going on, if it's limited to one frequency you may
be able to just switch to a more benign frequency and have fun.

I've tried 5 different frequencies; all act the same way.


You could switch to flying control line, but that gets difficult with
gliders.

I think at that point it becomes a kite!

"P. Venkman" wrote in message
om...
This is somewhat off topic; I apologize, but it seems like the people
that hang out here might actually be able to help me with my problem.

I fly radio control gliders. I recently purchased a new transmitter
(a Royal Evo 9 with synth module, for those that might care). I'm in
the US so this broadcasts on 72MHz.

I have problems with this transmitter at one particular flying site
that's right next to a military base. The xmitter is fine at other
locations, and all the gliders respond just fine to my 'old' xmitter
at this site. I've done a bunch of things and it really is just the
new xmitter at this particular flying site.

It seems like there must be an interference problem with some signal
being broadcast from the military base. I've tried to shield the
transmitter without much improvement. That makes me think the
offending signal may be coming in through the antenna.

Being relatively naive electronically, it seems like I could simply
insert a filter between the antenna and the rest of the transmitter
that passes through the 72 MHz signal but blocks everything else.
However, I'm smart enough to know I'm not that smart. That's why I'm
here.

Is it as simple as finding a filter that passes 72 MHz along and
splicing it in to the wire going to the antenna? Is that likely to
cause other problems (transmitting on the wrong frequency, overheating
the RF module due to impedance mismatch, sudden death)? Assuming I
can't find a filter that passes along precisely the frequency I want,
is it OK to put filters in series (like a high-pass plus a low-pass)?
And finally, am I just totally missing the boat here with this idea?
I'm open to other suggestions.

Here's an idea. How about talking to the senior radio technician on the
military base? Just maybe he/she would have the answer.

73
Roger ZR3RC

"P. Venkman" wrote in message
om...
This is somewhat off topic; I apologize, but it seems like the people
that hang out here might actually be able to help me with my problem.

I fly radio control gliders. I recently purchased a new transmitter
(a Royal Evo 9 with synth module, for those that might care). I'm in
the US so this broadcasts on 72MHz.

I have problems with this transmitter at one particular flying site
that's right next to a military base. The xmitter is fine at other
locations, and all the gliders respond just fine to my 'old' xmitter
at this site. I've done a bunch of things and it really is just the
new xmitter at this particular flying site.

It seems like there must be an interference problem with some signal
being broadcast from the military base. I've tried to shield the
transmitter without much improvement. That makes me think the
offending signal may be coming in through the antenna.

Being relatively naive electronically, it seems like I could simply
insert a filter between the antenna and the rest of the transmitter
that passes through the 72 MHz signal but blocks everything else.
However, I'm smart enough to know I'm not that smart. That's why I'm
here.

Is it as simple as finding a filter that passes 72 MHz along and
splicing it in to the wire going to the antenna? Is that likely to
cause other problems (transmitting on the wrong frequency, overheating
the RF module due to impedance mismatch, sudden death)? Assuming I
can't find a filter that passes along precisely the frequency I want,
is it OK to put filters in series (like a high-pass plus a low-pass)?
And finally, am I just totally missing the boat here with this idea?
I'm open to other suggestions.

Here's an idea. How about talking to the senior radio technician on the
military base? Just maybe he/she would have the answer.

73
Roger ZR3RC

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

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

Might be kind of tough to pin down. IF they're using H.F. and probably up
into the GHz region and maybe even as low as the L.F. area to transmit, any
one of those transmitters OR a harmonic OR a clashing of all or any - could
be causing the problem. Given he said Crystal control planes work there but
not Synthesized units and given he said the planes operate ok elsewhere,
leads me to believe that the synthesized receiver (all of those he has
tried) is coming unlocked due to RF overload from something. Synthesized
receivers are nice, but they do have their draw backs. I've had battles with
them too in tight RF areas. Some places, a crystal IS better. Antiquated
maybe, but if it works, what the hell........ Just my opinion. I'm not an RF
engineer, but work around RF a lot. I've seen lots of weird stuff.

Lou

"Roger Conroy" wrote in message
...

"P. Venkman" wrote in message
om...
This is somewhat off topic; I apologize, but it seems like the people
that hang out here might actually be able to help me with my problem.

I fly radio control gliders. I recently purchased a new transmitter
(a Royal Evo 9 with synth module, for those that might care). I'm in
the US so this broadcasts on 72MHz.

I have problems with this transmitter at one particular flying site
that's right next to a military base. The xmitter is fine at other
locations, and all the gliders respond just fine to my 'old' xmitter
at this site. I've done a bunch of things and it really is just the
new xmitter at this particular flying site.

It seems like there must be an interference problem with some signal
being broadcast from the military base. I've tried to shield the
transmitter without much improvement. That makes me think the
offending signal may be coming in through the antenna.

Being relatively naive electronically, it seems like I could simply
insert a filter between the antenna and the rest of the transmitter
that passes through the 72 MHz signal but blocks everything else.
However, I'm smart enough to know I'm not that smart. That's why I'm
here.

Is it as simple as finding a filter that passes 72 MHz along and
splicing it in to the wire going to the antenna? Is that likely to
cause other problems (transmitting on the wrong frequency, overheating
the RF module due to impedance mismatch, sudden death)? Assuming I
can't find a filter that passes along precisely the frequency I want,
is it OK to put filters in series (like a high-pass plus a low-pass)?
And finally, am I just totally missing the boat here with this idea?
I'm open to other suggestions.

Here's an idea. How about talking to the senior radio technician on the
military base? Just maybe he/she would have the answer.

73
Roger ZR3RC

Might be kind of tough to pin down. IF they're using H.F. and probably up
into the GHz region and maybe even as low as the L.F. area to transmit, any
one of those transmitters OR a harmonic OR a clashing of all or any - could
be causing the problem. Given he said Crystal control planes work there but
not Synthesized units and given he said the planes operate ok elsewhere,
leads me to believe that the synthesized receiver (all of those he has
tried) is coming unlocked due to RF overload from something. Synthesized
receivers are nice, but they do have their draw backs. I've had battles with
them too in tight RF areas. Some places, a crystal IS better. Antiquated
maybe, but if it works, what the hell........ Just my opinion. I'm not an RF
engineer, but work around RF a lot. I've seen lots of weird stuff.

Lou

"Roger Conroy" wrote in message
...

"P. Venkman" wrote in message
om...
This is somewhat off topic; I apologize, but it seems like the people
that hang out here might actually be able to help me with my problem.

I fly radio control gliders. I recently purchased a new transmitter
(a Royal Evo 9 with synth module, for those that might care). I'm in
the US so this broadcasts on 72MHz.

I have problems with this transmitter at one particular flying site
that's right next to a military base. The xmitter is fine at other
locations, and all the gliders respond just fine to my 'old' xmitter
at this site. I've done a bunch of things and it really is just the
new xmitter at this particular flying site.

It seems like there must be an interference problem with some signal
being broadcast from the military base. I've tried to shield the
transmitter without much improvement. That makes me think the
offending signal may be coming in through the antenna.

Being relatively naive electronically, it seems like I could simply
insert a filter between the antenna and the rest of the transmitter
that passes through the 72 MHz signal but blocks everything else.
However, I'm smart enough to know I'm not that smart. That's why I'm
here.

Is it as simple as finding a filter that passes 72 MHz along and
splicing it in to the wire going to the antenna? Is that likely to
cause other problems (transmitting on the wrong frequency, overheating
the RF module due to impedance mismatch, sudden death)? Assuming I
can't find a filter that passes along precisely the frequency I want,
is it OK to put filters in series (like a high-pass plus a low-pass)?
And finally, am I just totally missing the boat here with this idea?
I'm open to other suggestions.

Here's an idea. How about talking to the senior radio technician on the
military base? Just maybe he/she would have the answer.

73
Roger ZR3RC

"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.

"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.

"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