Fairchild Club Forum

'I am having a problem with radio interference but only on the
receiving end. It sounds to me like spark noise (lower frequency
noise at maybe an estimated 10 times per second that varies with
engine rpm). As far as I can tell, it has always been there and I was
hoping that it would go away when we had the engine overhauled and a
new electrical/radio system put in a couple of years ago. However,
the problem still exists today. To the best of my knowledge,
everything is shielded and we have a DC line filter installed. The
comm antenna is located in the center of the airplane directly beneath
the rudder pedals. I was thinking that maybe it is a lose wire
somewhere but we replaced the wiring harness (so why would it continue
both before and after). Or perhaps it is something on the engine that
is not properly grounded? What are your impressions or experiences
about my problem or one similar?

Regards,

Bradley Bormuth
F24W-40 NC28640'

'Dear Bradley
I had the same problem with my F24 and found that the generator had worn out and was earthing through the main drive or something, any way after a overhauling the generator the problem stopped.
Hope it helps
James Bryan

----- Original Message ----
From: Bradley Bormuth
To: fairchildclub@yahoogroups.com
Sent: Wednesday, 6 February, 2008 6:41:42 PM
Subject: [fairchildclub] Radio Noise













I am having a problem with radio interference but only on the

receiving end. It sounds to me like spark noise (lower frequency

noise at maybe an estimated 10 times per second that varies with

engine rpm). As far as I can tell, it has always been there and I was

hoping that it would go away when we had the engine overhauled and a

new electrical/radio system put in a couple of years ago. However,

the problem still exists today. To the best of my knowledge,

everything is shielded and we have a DC line filter installed. The

comm antenna is located in the center of the airplane directly beneath

the rudder pedals. I was thinking that maybe it is a lose wire

somewhere but we replaced the wiring harness (so why would it continue

both before and after). Or perhaps it is something on the engine that

is not properly grounded? What are your impressions or experiences

about my problem or one similar?



Regards,



Bradley Bormuth

F24W-40 NC28640






























[Non-text portions of this message have been removed]'

'Brad,
For what it's worth. I did have a fairly loud static noise some time
back. It was RPM related. It apparently wasn't heard through
transmissions. I did three or four things to improve that, and it
did. I'm just not sure which fix caused the improvement.

Both mags completely rebuilt. (Fresno airparts Co)
Installed those little "ground terminal shields" on each mag.
New shielded harness built. (Fresno Airparts Co)
Radio noise filters purchased and installed at each mag. (Sac
Skyranch part)
Also my setup already had shielded "P' leads to the mag switch.
Double check only one end of the shielding is grounded. Easier if
it's grounded at the mag.
Also some type of flat copper ground strap is a good idea, grounding
the engine block to the airframe. Keep it short in length. You may
also want to give the generator and regulator capacitors some
attention. Have fun.

Tom
F24R46
Hanford,Ca'

'I had much the same problem on an A-65 that I had.

If there is any place where you can physically touch the P-lead, without shielding, it will radiate noise.

I had the leads on the backside of the Mag switch covered with a light weight steel cap that necked down to a diameter only slightly larger than the wire bundle. The shielding braid was electrically bonded to that.

On the Mag end, I used Bendix Shield P/N 10-16140Z on both mags. There is other parts associated with it, and the braid was also terminated into the input end of the shield. I was using a SF4 versus the SF6.

I also put one of the noise filters at the Mag, and routed and tied the grounds together at the Mag.

And another reminder. Take a look at the wire that feeds the DC Fuse buss. The OE wiring had an 18 ga. wire. It is a wonder that I, or the previous owners, didn't have a fire. It should be possibly as large as a 6 ga. or as small as a 10 ga., but that would depend on what your load is. Mine will need to be a 6 or as small as a 8 ga. My landing light is 20 amps., all by itself. Don't hold me to the numbers, I haven't ran the numbers to see what my total will be.

Regarding Mag overhaul. Don't let someone do it on the cheap. My old Cub needed a 500hr overhaul of the mags.(After I sold it) They didn't tear it all the way down and lub the shaft that goes into the distributor cylinder. So within a few hours there after the distributor started rattling/vibrating at low RPM. It usually quit once the RPM got above 1000 RPM. They didn't think Mags, because that just overhauled them. Or at least paid for it. So they tore down the back end of the motor only to find nothing. A dab of special grease about the size of a big match head was all that was required. The shaft fits into a brass bushing inside the distributor, and the major load for the distributor is carried on a small ball bearing set on the gear end of the shaft.

(My spell check only works in French, Sorry)
Bob

[Non-text portions of this message have been removed]'

'Sorry to butt in...I am trying to start a new topic:


I am having trouble finding blueprints or drawings which will show how the
firewall structure is designed for the attachment of engine mount brackets on
the Warner 165 powered Fairchild 24. I want to convert my 1937 F24G from 145
to 165. I have a engine mount and engine. The Smithsonian drawing list
does not show a Fairchild 24 with the Warner 165....only the 1946 Ranger
version. I know this has been done already.
Does anyone out there have a set of drawings or blueprints which will enable
me to make this conversion?
I visited a 1937 F24G today...which has the Warner 185. This uses the same
engine mount...but I was unable to tear it apart to see how it was done.
Any help will be appreciated very much.
Thanks!

Richard Hawley NC19105



**************Biggest Grammy Award surprises of all time on AOL Music.
(http://music.aol.com/grammys/pictures/never-won-a-grammy?NCID=aolcmp003000000025
48)


[Non-text portions of this message have been removed]'

'I am having trouble finding blueprints or drawings which will show
how the firewall structure is designed for the attachment of engine
mount brackets on the Warner 165 powered Fairchild 24. I want to
convert my 1937 F24G from 145 to 165. I have a engine mount and
engine. The Smithsonian drawing list does not show a Fairchild 24
with the Warner 165....only the 1946 Ranger version. I know this
has been done already. Does anyone out there have a set of drawings
or blueprints which will enable me to make this conversion?

I visited a 1937 F24G today...which has the Warner 185. This uses
the same engine mount...but I was unable to tear it apart to see
how it was done. Any help will be appreciated very much.
Thanks!
Richard Hawley NC19105

I have spent all evening researching my History records and the STC
that is entered in my Log is SA2747CE but the FAA data records
doesn't show that number.

I'll have more after talking to FSDO on who owns the STC and who
holds the Blue Prints which tells how to install the Warner 165.'

'Bradley and all,I have the exact same problem with radio noise in my Meyers OTW with a Warner 165.  Have done quite a bit of troubleshooting and still have reception noise.  Any ideas would be most appreciated.
Thanks,
Jay'

'I would like to help, but not today.  The last time (June 1974) that I flew behind a 165 hp Warner, my plug wires were Packard 440 (unshielded) and I was happy with my VHT-3 (6 channel Tube type) radio.   On a Sunday afternoon, I could cruise along and listen to a baseball game.  The low end of the receiver, as receivers go,  well...the frequency tuning was a bit on the loose side. You could do like Harold Neuman did years ago with his Monocoupe.  When he wanted to talk, he shut the motor off.  It was a bit hard to manage when on the ground. Bob

On Sunday, August 24, 2014 7:41 AM, "jayherrin@bellsouth.net [fairchildclub]" wrote:


  Bradley and all,I have the exact same problem with radio noise in my Meyers OTW with a Warner 165.  Have done quite a bit of troubleshooting and still have reception noise.  Any ideas would be most appreciated.
Thanks,
Jay #ygrps-yiv-2069972991 #ygrps-yiv-2069972991yiv3510501238 #ygrps-yiv-2069972991yiv3510501238 -- #ygrps-yiv-2069972991yiv3510501238ygrp-mkp { border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;} #ygrps-yiv-2069972991 #ygrps-yiv-2069972991yiv3510501238 #ygrps-yiv-2069972991yiv3510501238ygrp-mkp hr { border:1px solid #d8d8d8;} #ygrps-yiv-2069972991 #ygrps-yiv-2069972991yiv3510501238 #ygrps-yiv-2069972991yiv3510501238ygrp-mkp #ygrps-yiv-2069972991yiv3510501238hd { color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;} #ygrps-yiv-2069972991 #ygrps-yiv-2069972991yiv3510501238 #ygrps-yiv-2069972991yiv3510501238ygrp-mkp #ygrps-yiv-2069972991yiv3510501238ads { margin-bottom:10px;} #ygrps-yiv-2069972991 #ygrps-yiv-2069972991yiv3510501238 #ygrps-yiv-2069972991yiv3510501238ygrp-mkp .ygrps-yiv-2069972991yiv3510501238ad { padding:0 0;} #ygrps-yiv-2069972991 #ygrps-yiv-2069972991yiv3510501238 #ygrps-yiv-2069972991yiv3510501238ygrp-mkp 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'

'Radio noise is almost always due to poor grounding, or something grounded to the frame that shouldn't be grounded.  Check you mike/phone jacks and make sure that:
1. they're not using the frame as the ground return.
2. that the jacks themselves are isolated from ground.  There should be a fiber washer on one side with a shoulder to keep the jack centered in the hole the other side should be a phenolic or similar washer.
3. make sure the radio it self is grounded correctly.

Bill

On Sun, Aug 24, 2014 at 10:41 AM, jayherrin@bellsouth.net [fairchildclub] wrote:
 
Bradley and all,I have the exact same problem with radio noise in my Meyers OTW with a Warner 165.  Have done quite a bit of troubleshooting and still have reception noise.  Any ideas would be most appreciated.
Thanks,
Jay

'