PCAS interfering with radio

I'm getting strong interfrence on 123.3, 123.5, 122.8
& 121.5 whit my ZAON PCAS using ships power. No problem
if I use PCAS internal pen-cels. Anybody else had this
problem, how'd you fix it?
JJ

John Sinclair wrote:
I'm getting strong interfrence on 123.3, 123.5, 122.8
& 121.5 whit my ZAON PCAS using ships power. No problem
if I use PCAS internal pen-cels. Anybody else had this
problem, how'd you fix it?

Which Zaon unit was it? I just wired in a Zaon MRX, but didn't think to
test the radio. Tomorrow!


--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

I sent my ZAON MRX, back for a fix, about 2 weeks ago.
Nothing yet. A local electronic whiz made me a choke
to place in the power supply leads, but I haven't tried
it because I don't have the unit. My PCAS was hitting
all the low frequencies hard, so I believe it is sending
the interfrence back down the 12v leads. OK, on internal
3v pen cells.
I'll post when I get it back from ZAON Looks like a
neat unit. I live near Hwy. 50 which has a lot of IFR
traffic (I follow roads) and I have watched traffic
march down from 5 miles to 1 mile where I get 2 beeps,
then 4 beebs inside 1 mile. All this with an altitude
difference read-out (+800)................just what
we want to know.

The other night, I was playing with it and Pat asked,
'what's that beeping'. I replied, can't talk right
now, I'm in a hard turn looking for someone inside
a mile at +400 feet and closing fast!
Cheers,
JJ


At 03:12 07 March 2007, Eric Greenwell wrote:
John Sinclair wrote:
I'm getting strong interfrence on 123.3, 123.5, 122.8
& 121.5 whit my ZAON PCAS using ships power. No problem
if I use PCAS internal pen-cels. Anybody else had
this
problem, how'd you fix it?

Which Zaon unit was it? I just wired in a Zaon MRX,
but didn't think to
test the radio. Tomorrow!


--
Eric Greenwell - Washington State, USA
* Change 'netto' to 'net' to email me directly
* 'Transponders in Sailplanes' http://tinyurl.com/y739x4
* 'A Guide to Self-launching Sailplane Operation' at
www.motorglider.org

I sent my ZAON MRX, back for a fix, about 2 weeks ago.
Nothing yet. A local electronic whiz made me a choke
to place in the power supply leads, but I haven't tried
it because I don't have the unit. My PCAS was hitting
all the low frequencies hard, so I believe it is sending
the interfrence back down the 12v leads. OK, on internal
3v pen cells.
I'll post when I get it back from ZAON Looks like a
neat unit. I live near Hwy. 50 which has a lot of IFR
traffic (I follow roads) and I have watched traffic
march down from 5 miles to 1 mile where I get 2 beeps,
then 4 beebs inside 1 mile. All this with an altitude
difference read-out (+800)................just what
we want to know.

The other night, I was playing with it and Pat asked,
'what's that beeping'. I replied, can't talk right
now, I'm in a hard turn looking for someone inside
a mile at +400 feet and closing fast!
Cheers,
JJ


At 03:12 07 March 2007, Eric Greenwell wrote:
John Sinclair wrote:
I'm getting strong interfrence on 123.3, 123.5, 122.8
& 121.5 whit my ZAON PCAS using ships power. No problem
if I use PCAS internal pen-cels. Anybody else had
this
problem, how'd you fix it?

Which Zaon unit was it? I just wired in a Zaon MRX,
but didn't think to
test the radio. Tomorrow!


--
Eric Greenwell - Washington State, USA
* Change 'netto' to 'net' to email me directly
* 'Transponders in Sailplanes' http://tinyurl.com/y739x4
* 'A Guide to Self-launching Sailplane Operation' at
www.motorglider.org

Well, I got my PCAS MRX back from ZAON, they added
a EMI filter, but it's still breaking squelch on 123.3
& 5. So, I added a choke filter and she's quiet as
a mouse on ships power. The choke has 4 little coils
(2 in each power lead) with a capacitor going between
them. Can find out the exact description if anyone
want's it.
JJ
PS, I also added a sheet of black plastic (x-ray film)
to cut down reflections and extended it back to act
as glare shield.....slick as snot.


At 03:12 07 March 2007, Eric Greenwell wrote:
John Sinclair wrote:
I'm getting strong interfrence on 123.3, 123.5, 122.8
& 121.5 whit my ZAON PCAS using ships power. No problem
if I use PCAS internal pen-cels. Anybody else had
this
problem, how'd you fix it?

Which Zaon unit was it? I just wired in a Zaon MRX,
but didn't think to
test the radio. Tomorrow!


--
Eric Greenwell - Washington State, USA
* Change 'netto' to 'net' to email me directly
* 'Transponders in Sailplanes' http://tinyurl.com/y739x4
* 'A Guide to Self-launching Sailplane Operation' at
www.motorglider.org

John Sinclair wrote:


Well, I got my PCAS MRX back from ZAON, they added
a EMI filter, but it's still breaking squelch on 123.3
& 5. So, I added a choke filter and she's quiet as
a mouse on ships power. The choke has 4 little coils
(2 in each power lead) with a capacitor going between
them. Can find out the exact description if anyone
want's it.
JJ
PS, I also added a sheet of black plastic (x-ray film)
to cut down reflections and extended it back to act
as glare shield.....slick as snot.


John's choke is a real overkill, but it is "guarranteed to work".
Coils are JW Miller & Bourns FB20010-3B-RC (DigiKey M8694-ND) cost
about 70-85 cents each depending how many you buy. Capacitor is a
standard ceramic 0.47 microFarad. I may have used 1 uF. I do not have
part number, but there is nothing particularly special about it (just
do not get one rated for 1kV ).

----WWWW-----WWWW----
I
-----
-----
I
----WWWW-----WWWW----

Best I can do for schematic is above. Put it as close to the noise
generator as possible.

Cheers,

Henryk Birecki