Return-Path: Sender: (Marvin Kaye) To: lml Date: Thu, 05 Jun 2003 01:22:33 -0400 Message-ID: X-Original-Return-Path: Received: from imo-d03.mx.aol.com ([205.188.157.35] verified) by logan.com (CommuniGate Pro SMTP 4.1b7) with ESMTP id 2403093 for lml@lancaironline.net; Thu, 05 Jun 2003 00:53:56 -0400 Received: from Sky2high@aol.com by imo-d03.mx.aol.com (mail_out_v36.3.) id q.f9.2dd830a8 (30960); Thu, 5 Jun 2003 00:53:48 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Thu, 5 Jun 2003 00:53:47 EDT Subject: Applying Black Arts to solving RFI interference! X-Original-To: lml@lancaironline.net, davem@visionmicrosystems.com, Cozyone2@aol.com MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_f9.2dd830a8.2c1026db_boundary" X-Mailer: Unknown sub 191 --part1_f9.2dd830a8.2c1026db_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Some of you may remember that months ago I asked for help with a long time problem that had every temperature reading take a dip, along with the autopilot on altitude hold, every time the PTT was pushed. A friend of mine (Doug) had a similar problem with his Cozy Mark IV. It was severe - OIL, OAT, CHT and EGT would all take a plunge with the oil dropping 30 degrees, OAT 14, CHT 200 (causing the cyl chill warning light to come on). The auto pilot would take the nose down if altitude hold was engaged. Doug and I had many discussions with David McCluskey at VM and Doug also talked to Bob Nuckolls who suggested we consult with the Air Force's secret hangar people about RFI. Hmmmpf. David suggested we start by using ferrous toroids on the oil temperature leads and sure enough, the oil temp only dropped 8 degrees after they were applied. Now for the Black Art. First, Doug rewired his two comm antennas (located in his winglets) with RG400 to try to eliminate "line leakage" since the cheaper RG50 is well known to be "leaky". He also got rid of connectors at the wing roots - this required some pulling and routing. While leaving a 2 foot loop laying on the fuselage floor, but near the cable channel carrying other low voltage wires, a test was made. I don't remember what the temperatures did, but every time the transmit button was pushed his alternator field breaker would pop (B&C LR3 Regulator). Just rerouting the antenna lines outside the wire channel and getting rid of the loop stopped the breaker from popping. Second, let me set up my situation: The Radio Stack - from top down Monroy traffic alerter Terra Audio Panel Garmin 430 Terra Com2 - Terra Transponder Hobbs meter - Terra ADF (for listening to Rush) The right side of the panel is full of lights and switches, the ADF indicator, 8 very flat EPI 800 displays and at the far right are two vertical rows of circuit breakers. Forward of the panel and at the bottom is a large grounded aluminum sheet used as a mounting base. Forward of the breakers are the fast-on ground connections and on legs above that is a 20-fuse fast-on block. Forward of the displays and mounted on the plate is the special VM annunciator/IO connector block. The VM computer sits on legs above that and is surrounded by an aluminum box open fore and aft (aft for wires). On the top of that box are 3 dimmer circuits and the automatic fuel system brain box. At the forward edge of the plate and in front of the VM computer is the ACK encoder. Velcroed to the inboard vertical side of the box around the VM computer was the Comant antenna switcher for the lines from COM1 and COM2 and the RG50 cable that runs from there forward, down, under the floor boards and thru the tunnel to the com antenna in the vertical stabilizer. More Black Art!!!! Learning from Doug's wire movements (1st and 2nd in A minor), I unstick the Comant unit and wedge it under all the wires coming out of the Terra audio panel, just above the 430 tray. I slightly reroute the antenna lines to the box and replace the 2 foot line to the Garmin 430 (the most powerful radio) with RG400. I go fly with the autopilot on alt hold - its a beautiful day. I dial in an unused frequency and push the PTT for 5 seconds, 10 seconds 15 seconds. The oil temp drops 1 degree, the CHT and EGT not at all, the OAT in the Rocky Mountain instruments Micro-encoder does not change, the VM OAT drops only 4 degrees C (who cares? Toroids can be added later) and there is no dive from the autopilot. If only we could see RFI. I will not move the Comant unit anywhere else and if you touch my antenna leads I will... well, let's just say you wouldn't be able to give the FBI your finger prints ever again. Scott Krueger Sky2high@aol.com LNC2 N92EX IO320 Aurora, IL (KARR) --part1_f9.2dd830a8.2c1026db_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Some of you may remember that months ago I asked for help with a long t= ime problem that had every temperature reading take a dip, along with the au= topilot on altitude hold, every time the PTT was pushed.  A friend of m= ine (Doug) had a similar problem with his Cozy Mark IV.
 
It was severe - OIL, OAT, CHT and EGT would all take a plunge with= the oil dropping 30 degrees, OAT 14, CHT 200 (causing the cyl chill warning= light to come on).  The auto pilot would take the nose down if altitud= e hold was engaged.  Doug and I had many discussions with David Mc= Cluskey at VM and Doug also talked to Bob Nuckolls who suggested we consult=20= with the Air Force's secret hangar people about RFI.  Hmmmpf. Davi= d suggested we start by using ferrous toroids on the oil temperature leads a= nd sure enough, the oil temp only dropped 8 degrees after they were applied.=
 
Now for the Black Art.
 
First, Doug rewired his two comm antennas (located in his winglets) wit= h RG400 to try to eliminate "line leakage" since the cheaper RG50 is well kn= own to be "leaky".  He also got rid of connectors at the wing roots - t= his required some pulling and routing.   While leaving a 2 foot lo= op laying on the fuselage floor, but near the cable channel carrying ot= her low voltage wires, a test was made.  I don't remember what the temp= eratures did, but every time the transmit button was pushed his alternator f= ield breaker would pop (B&C LR3 Regulator).  Just rerouting the ant= enna lines outside the wire channel and getting rid of the loop stopped the=20= breaker from popping.
 
Second, let me set up my situation:
 
The Radio Stack - from top down
Monroy traffic alerter
Terra Audio Panel
Garmin 430
Terra Com2 - Terra Transponder
Hobbs meter   - Terra ADF (for listening to Rush)
 
The right side of the panel is full of lights and switches, the AD= F indicator, 8 very flat EPI 800 displays and at the far right are two verti= cal rows of circuit breakers.  Forward of the panel and at the bottom i= s a large grounded aluminum sheet used as a mounting base.  Forwar= d of the breakers are the fast-on ground connections and on legs above=20= that is a 20-fuse fast-on block.  Forward of the displays and= mounted on the plate is the special VM annunciator/IO connector block. = ; The VM computer sits on legs above that and is surrounded by an alumi= num box open fore and aft (aft for wires).  On the top of that box are=20= 3 dimmer circuits and the automatic fuel system brain box. At the forwa= rd edge of the plate and in front of the VM computer is the ACK encoder.&nbs= p; Velcroed to the inboard vertical side of the box around the VM computer <= U>was the Comant antenna switcher for the lines from COM1 and COM2=20= and the RG50 cable that runs from there forward, down, under the floor=20= boards and thru the tunnel to the com antenna in the vertical stabilizer.
 
More Black Art!!!!
 
Learning from Doug's wire movements (1st and 2nd in A minor), I unstick= the Comant unit and wedge it under all the wires coming out of the Terra au= dio panel, just above the 430 tray.  I slightly reroute the antenna lin= es to the box and replace the 2 foot line to the Garmin 430 (the most powerf= ul radio) with RG400.  I go fly with the autopilot on alt hold - its a=20= beautiful day.  I dial in an unused frequency and push the PTT for= 5 seconds, 10 seconds 15 seconds.  The oil temp drops 1 degree, the CH= T and EGT not at all, the OAT in the Rocky Mountain instruments Micro-encode= r does not change, the VM OAT drops only 4 degrees C (who car= es? Toroids can be added later) and there is no dive from the autopilot.&nbs= p;
 
If only we could see RFI.
 
I will not move the Comant unit anywhere else and if you touc= h my antenna leads I will... well, let's just say you  wouldn't be able= to give the FBI your finger prints ever again. 
 
Scott Krueger=
Sky2high@aol.com
LNC2 N92EX IO320 Aurora, IL (KARR)
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