From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: radio tx problem
Date: Sun, 12 Jan 2020 07:48:48 +0800
References: <list-13383191@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-13383191@logan.com>
Message-Id: <4FEDDD0B-98E5-4743-8226-57D2A1A2C5DE@gmail.com>

Hi Finn.

Yes Plastic, so RFI often problematic.

And yes I agree. Fix the source of the RFI if possible.

Antenna is a dipole glassed into the fin so basically impossible to =
rectify or change the older coax to better RG400.

I=E2=80=99m putting an antenna analyser on it today so hope to get VSWR =
etc.=20
If its no good I might have to install a new antenna system.
Wondering about:
    Iinternal - say a Bob Archer SA-006 or 008 at $180USD plus shipping =
to Australia=20
    External and installing a ground plane?

In regard to Tracy=E2=80=99s fix. I haven't done any RFI decoupling, but =
I thought 10nF might be a better choice for 120Mhz?

Thanks Finn.

Steve
=20


> On 11 Jan 2020, at 10:30 pm, Finn Lassen finn.lassen@verizon.net =
<flyrotary@lancaironline.net> wrote:
>=20
> Steve,
>=20
> This is a composite airplane?
>=20
> Before starting to eliminate effects, I'd suggest you make sure that =
the transmitter, cables and antenna is not the cause. You're sure you =
have a real good coax - perfect shield/ground on both transmitter and =
antenna end? Good solid connector grounds -- no corrosion? How about =
grounding of transmitter (path to battery)?
>=20
> You could try a handheld transmitter for testing.
>=20
> In Tracy's fix, notice the period. It's 100nF not 1uF. Probably not =
that important but could slow the MAP sensor response.
>=20
> Finn
>=20
> On 1/10/2020 6:31 PM, Stephen Izett stephen.izett@gmail.com wrote:
>> Hi people
>>=20
>> Ive had an opportunity yesterday to begin the journey of chasing down =
this miss in the engine / EC2 on radio TX.
>> I discovered that the gremlin is getting into the EC2=E2=80=99s A =
computer but not the B
>> Switching to B there is no hint of a problem.
>>=20
>> I=E2=80=99m thinking there are two substantive differences between =
EC2 A & B processors/computers.
>> 1. The B computer has the capacity to turn off the leading and =
trailing coils for testing, that the A computer doesn=E2=80=99t have.
>> 2. The A computer measures the intake air temp to determine O2 =
molecules in intake charge which the B computer doesn=E2=80=99t.
>>=20
>> So I=E2=80=99m wondering if the intake temp input (thermistor) on the =
EC2 A computer is the antenna for the RFI to get in.
>> Disconnecting this line to the the EC2 A computer in order to =
identify if this is the problem is going to be a pain but maybe a =
necessary fault finding path.
>>=20
>> Has Tracy or anyone put a small Capacitor on inputs to filter RFI?
>>=20
>> Thanks for any input you can offer.
>>=20
>> Steve
>>=20
>>=20
>>=20
>> --
>> Homepage:  http://www.flyrotary.com/
>> Archive and UnSub:   =
http://mail.lancaironline.net:81/lists/flyrotary/List.html
>>=20
>=20
>=20
> --
> Homepage:  http://www.flyrotary.com/
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