In article ,
P. Venkman wrote:

| 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.

You haven't actually told us what the problem is.

Is the computer in your transmitter crashing? (interfering with the transmitter)
Are the servos in your plane jittering? (interfering with the receiver)
Are you seeing reduced range or something? (interfering with the receiver)

| 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.

We'll need to know what the actual problem is. Shielding your
transmitter isn't going to do much unless the interference is actually
affecting your transmitter (possible, but unlikely) rather than your
receiver.

| 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.

If the problem is interference to your receiver, doing this at your
transmitter won't help at all. You'd need to do it at the receiver.

Some people have had good luck simply wrapping their receiver (just
the receiver, not the antenna) in tin foil. Twisting the servo and
power wires round and round can also help reduce interference to the
receiver as well, and you can get chokes to wrap your servo wires
around as well.

Very very few people put additional filters on their R/C receivers.

Are there any pager towers nearby? Pager companies use the spaces
between the R/C channels to talk to pagers, and can use hundreds of
watts -- this has definately been known to overload R/C receivers and
crash planes. (In that case, the fix would be to 1) do the tin
foil/choke thing and 2) try a different frequency. (Your transmitter
is synthesized, so all you need is a new receive crystal.)

| However, I'm smart enough to know I'm not that smart.

That's a pretty good sort of smart to be!

| Is it as simple as finding a filter that passes 72 MHz along and
| splicing it in to the wire going to the antenna?

Probably not, unless your problem really is with the transmitter
computer crashing.

Which receiver are you using? The cheap park flier ones don't handle
interference well at all.

Do other people fly at this site? Your radio should be able to talk
to any plane, so try switching frequencies and picking the proper
shift and see if you can do a proper range check with their plane.
(Or another plane if you have more.)

You might also try asking in rec.models.rc.air, though they'll
probably tell you the same things I did.

(And yes, I fly R/C too.)

--
Doug McLaren, Reserve your bear to right arms.

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

Tim Wescott wrote in message ...

P. Venkman wrote:


SNIP


Is there any way to make this work?

Not without more information, which was why I suggested a test.

Did you do the range check against the other transmitters with the TX
antenna collapsed? If so, then you've done a fine test of how well your
TX will work compared to others -- with everyone's antennas are
collapsed. If you normally fly it with the antenna _out_ then you need
to test it that way, and find some other way of attenuating the signal
to the receiver -- like rolling up _it's_ antenna.

You obviously have a problem with that particular TX, which is why I'm
suggesting a look at the TX first. Another question you can ask is does
the TX have the same problem with other receivers? On other
frequencies? Do you have another plane with a different brand receiver,
or a buddy with same, that you can try at the problem site? This may be
a valid thing to try.

I've done the range check with the antenna in; under normal
circumstances the range is further than I can see with the antenna
out. I can try rolling up the receiver antenna.

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.

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

Tim Wescott wrote in message ...

P. Venkman wrote:


SNIP


Is there any way to make this work?

Not without more information, which was why I suggested a test.

Did you do the range check against the other transmitters with the TX
antenna collapsed? If so, then you've done a fine test of how well your
TX will work compared to others -- with everyone's antennas are
collapsed. If you normally fly it with the antenna _out_ then you need
to test it that way, and find some other way of attenuating the signal
to the receiver -- like rolling up _it's_ antenna.

You obviously have a problem with that particular TX, which is why I'm
suggesting a look at the TX first. Another question you can ask is does
the TX have the same problem with other receivers? On other
frequencies? Do you have another plane with a different brand receiver,
or a buddy with same, that you can try at the problem site? This may be
a valid thing to try.

I've done the range check with the antenna in; under normal
circumstances the range is further than I can see with the antenna
out. I can try rolling up the receiver antenna.

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.

"Harold E. Johnson" wrote in message news:vIbic.12068$IW1.760683@attbi_s52...
Lots of other people fly at the same location with a variety of
equipement with no trouble. I've flown a variety of different gliders
there with my old transmitter and never had a problem. I really don't
think there's a conflicting 72 MHz signal.

It really is just this transmitter at this particular site - other
transmitters at the same site are fine, and this transmitter at other
sites is just fine.

Is there any way to make this work?

You didn't say, but if that "military site" is an airport, there's a
localizer beacon that's probably just off the end of the runway and is on 75
MHz. Could readily be strong enough to give your receiver trouble.

W4ZCB


It's not an airport, but who knows what they have blasting away on any
number of frequencies. I don't have the equipment to check it out.

"Harold E. Johnson" wrote in message news:vIbic.12068$IW1.760683@attbi_s52...
Lots of other people fly at the same location with a variety of
equipement with no trouble. I've flown a variety of different gliders
there with my old transmitter and never had a problem. I really don't
think there's a conflicting 72 MHz signal.

It really is just this transmitter at this particular site - other
transmitters at the same site are fine, and this transmitter at other
sites is just fine.

Is there any way to make this work?

You didn't say, but if that "military site" is an airport, there's a
localizer beacon that's probably just off the end of the runway and is on 75
MHz. Could readily be strong enough to give your receiver trouble.

W4ZCB


It's not an airport, but who knows what they have blasting away on any
number of frequencies. I don't have the equipment to check it out.

See answers in line:

(Doug McLaren) wrote in message ...
In article ,
P. Venkman wrote:

| 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.

You haven't actually told us what the problem is.

Is the computer in your transmitter crashing? (interfering with the transmitter)
Are the servos in your plane jittering? (interfering with the receiver)
Are you seeing reduced range or something? (interfering with the receiver)

The computer doesn't crash; the servos jitter badly; range is reduced
to zero, as the jittering starts immediately.

I know reading this you're going to think it's the reciever, but
please read through my other posts. It's not. I've tried 5 different
recievers (4 brands) on different frequencies, and with my old
transmitter all are fine and with the new transmitter they all glitch.
However, it's only at this particular site - anyplace else all the
receivers are glitch-free with the new transmitter.


| 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.

We'll need to know what the actual problem is. Shielding your
transmitter isn't going to do much unless the interference is actually
affecting your transmitter (possible, but unlikely) rather than your
receiver.

| 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.

If the problem is interference to your receiver, doing this at your
transmitter won't help at all. You'd need to do it at the receiver.

Some people have had good luck simply wrapping their receiver (just
the receiver, not the antenna) in tin foil. Twisting the servo and
power wires round and round can also help reduce interference to the
receiver as well, and you can get chokes to wrap your servo wires
around as well.

Tried all of this; no help.


Very very few people put additional filters on their R/C receivers.

Are there any pager towers nearby? Pager companies use the spaces
between the R/C channels to talk to pagers, and can use hundreds of
watts -- this has definately been known to overload R/C receivers and
crash planes. (In that case, the fix would be to 1) do the tin
foil/choke thing and 2) try a different frequency. (Your transmitter
is synthesized, so all you need is a new receive crystal.)

No pager towers, at least that I'm aware of. However the military
base has a large number of antennas and who knows what they're
broadcasting.


| However, I'm smart enough to know I'm not that smart.

That's a pretty good sort of smart to be!

| Is it as simple as finding a filter that passes 72 MHz along and
| splicing it in to the wire going to the antenna?

Probably not, unless your problem really is with the transmitter
computer crashing.

Well, the computer doesn't crash. I finally ran into another guy at
this site flying with an Evo; he had the crystal instead of the synth
version, and he had no trouble at all. I'm working on getting a
crystal module to try.


Which receiver are you using? The cheap park flier ones don't handle
interference well at all.

I've tried two Airtronics, an old RCD (they're Hitec now), a JR, and
an FMA M5. With the old transmitter (an Airtronics) they're all fine;
anyplace but that site they're all fine with the new transmitter too.
Try the new transmitter at that site, and they ALL glitch.


Do other people fly at this site? Your radio should be able to talk
to any plane, so try switching frequencies and picking the proper
shift and see if you can do a proper range check with their plane.
(Or another plane if you have more.)

This is a pretty popular site. I've seen lots of people flying lots
of different types of equipement at this site with no problems. I've
flown four different planes there with the old transmitter with no
problem.


You might also try asking in rec.models.rc.air, though they'll
probably tell you the same things I did.

I've asked a variety of places without much luck. Mostly it's been a
pattern of demonstrating I've tried all the reasonable things and it's
not a problem with the reciever, followed by suggestions that I either
just get another radio or fly at a different site. Neither of those
'solutions' are appealing, so I was hoping someone on this site (being
more technically knowledgable) might have a better idea.

BTW, I completely understand why people think it's the receiver to
start with. It practically always is. I tried three different
recievers myself before I finally started to think just maybe it was
the transmitter.


(And yes, I fly R/C too.)

See answers in line:

(Doug McLaren) wrote in message ...
In article ,
P. Venkman wrote:

| 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.

You haven't actually told us what the problem is.

Is the computer in your transmitter crashing? (interfering with the transmitter)
Are the servos in your plane jittering? (interfering with the receiver)
Are you seeing reduced range or something? (interfering with the receiver)

The computer doesn't crash; the servos jitter badly; range is reduced
to zero, as the jittering starts immediately.

I know reading this you're going to think it's the reciever, but
please read through my other posts. It's not. I've tried 5 different
recievers (4 brands) on different frequencies, and with my old
transmitter all are fine and with the new transmitter they all glitch.
However, it's only at this particular site - anyplace else all the
receivers are glitch-free with the new transmitter.


| 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.

We'll need to know what the actual problem is. Shielding your
transmitter isn't going to do much unless the interference is actually
affecting your transmitter (possible, but unlikely) rather than your
receiver.

| 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.

If the problem is interference to your receiver, doing this at your
transmitter won't help at all. You'd need to do it at the receiver.

Some people have had good luck simply wrapping their receiver (just
the receiver, not the antenna) in tin foil. Twisting the servo and
power wires round and round can also help reduce interference to the
receiver as well, and you can get chokes to wrap your servo wires
around as well.

Tried all of this; no help.


Very very few people put additional filters on their R/C receivers.

Are there any pager towers nearby? Pager companies use the spaces
between the R/C channels to talk to pagers, and can use hundreds of
watts -- this has definately been known to overload R/C receivers and
crash planes. (In that case, the fix would be to 1) do the tin
foil/choke thing and 2) try a different frequency. (Your transmitter
is synthesized, so all you need is a new receive crystal.)

No pager towers, at least that I'm aware of. However the military
base has a large number of antennas and who knows what they're
broadcasting.


| However, I'm smart enough to know I'm not that smart.

That's a pretty good sort of smart to be!

| Is it as simple as finding a filter that passes 72 MHz along and
| splicing it in to the wire going to the antenna?

Probably not, unless your problem really is with the transmitter
computer crashing.

Well, the computer doesn't crash. I finally ran into another guy at
this site flying with an Evo; he had the crystal instead of the synth
version, and he had no trouble at all. I'm working on getting a
crystal module to try.


Which receiver are you using? The cheap park flier ones don't handle
interference well at all.

I've tried two Airtronics, an old RCD (they're Hitec now), a JR, and
an FMA M5. With the old transmitter (an Airtronics) they're all fine;
anyplace but that site they're all fine with the new transmitter too.
Try the new transmitter at that site, and they ALL glitch.


Do other people fly at this site? Your radio should be able to talk
to any plane, so try switching frequencies and picking the proper
shift and see if you can do a proper range check with their plane.
(Or another plane if you have more.)

This is a pretty popular site. I've seen lots of people flying lots
of different types of equipement at this site with no problems. I've
flown four different planes there with the old transmitter with no
problem.


You might also try asking in rec.models.rc.air, though they'll
probably tell you the same things I did.

I've asked a variety of places without much luck. Mostly it's been a
pattern of demonstrating I've tried all the reasonable things and it's
not a problem with the reciever, followed by suggestions that I either
just get another radio or fly at a different site. Neither of those
'solutions' are appealing, so I was hoping someone on this site (being
more technically knowledgable) might have a better idea.

BTW, I completely understand why people think it's the receiver to
start with. It practically always is. I tried three different
recievers myself before I finally started to think just maybe it was
the transmitter.


(And yes, I fly R/C too.)

P. Venkman wrote:

Tim Wescott wrote in message ...

P. Venkman wrote:


Tim Wescott wrote in message ...


P. Venkman wrote:


SNIP


Is there any way to make this work?

Not without more information, which was why I suggested a test.

Did you do the range check against the other transmitters with the TX
antenna collapsed? If so, then you've done a fine test of how well your
TX will work compared to others -- with everyone's antennas are
collapsed. If you normally fly it with the antenna _out_ then you need
to test it that way, and find some other way of attenuating the signal
to the receiver -- like rolling up _it's_ antenna.

You obviously have a problem with that particular TX, which is why I'm
suggesting a look at the TX first. Another question you can ask is does
the TX have the same problem with other receivers? On other
frequencies? Do you have another plane with a different brand receiver,
or a buddy with same, that you can try at the problem site? This may be
a valid thing to try.


I've done the range check with the antenna in; under normal
circumstances the range is further than I can see with the antenna
out. I can try rolling up the receiver antenna.

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.

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.

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

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

P. Venkman wrote:

Tim Wescott wrote in message ...

P. Venkman wrote:


Tim Wescott wrote in message ...


P. Venkman wrote:


SNIP


Is there any way to make this work?

Not without more information, which was why I suggested a test.

Did you do the range check against the other transmitters with the TX
antenna collapsed? If so, then you've done a fine test of how well your
TX will work compared to others -- with everyone's antennas are
collapsed. If you normally fly it with the antenna _out_ then you need
to test it that way, and find some other way of attenuating the signal
to the receiver -- like rolling up _it's_ antenna.

You obviously have a problem with that particular TX, which is why I'm
suggesting a look at the TX first. Another question you can ask is does
the TX have the same problem with other receivers? On other
frequencies? Do you have another plane with a different brand receiver,
or a buddy with same, that you can try at the problem site? This may be
a valid thing to try.


I've done the range check with the antenna in; under normal
circumstances the range is further than I can see with the antenna
out. I can try rolling up the receiver antenna.

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.

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.

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

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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!