At 6:00 PM -0400 16/9/06, Alan NV8A wrote:
>
>We (Holland [MI] ARC) have used Honda EU1000i generators for at least the last
>three Field Days and have not encountered RFI problems.
Could you expand on this a little with a description of how the Hondas were
used, e.g., distance from the radios and antennas, any line or common mode
filters installed, running through batteries, battery chargers, or directly
into power supplies (and type pwr supplies), modifications, type power cords,
etc?
I've already demonstrated conclusively to myself that my Honda EU 1000i is
causing RFI on the line rather than through radiowaves (common mode) by moving
the inverter-generator far away from my antennas and radios although usually,
by necessity I need to run my Honda very close to my radios under normal
conditions (security: needs to be padlocked to my travel trailer's tongue;
doing same to a tree is not feasible in most of AZ). There is absolutely no
question that the Honda is the source of the RFI: turned off and operating on
batteries only, no RFI; turned on, RFI is at S6 to S9 levels, even through a
switching power supply. It's worse on 20m than on 30m which is better than 17m
which is better than 15m. 40m and 80m are bad, but not as bad as 20m. No effect
on 2m FM. I haven't checked 12m, 10m, nor 6m. FWIW, when the Honda is running,
I don't even bother turning on my AM broadcast radio; it is completely drowned
out.
MFJ came out with its MFJ-1164 line filter in a very timely manner for me
except when I promptly ordered it, MFJ promptly backordered it for 3 1/2
months. I was at the point of ordering a bunch of toroids and beads to do line
filtering the hard way. If it doesn't work, I'll go with Jim's recommendations
on the #31; I was thinking along the lines of #43.
At 4:50 PM -0700 16/9/06, Jim Brown wrote:
>W4EF's advice, posted via a link by someone else in this thread, is
>solid. Mike knows what he is talking about. One thing I would add to
>his advice, which is probably a couple of years old, is that the newer
>Fair-Rite #31 mix would do a much better job of filtering the lower HF
>bands. And with either #43 or #31, you MUST wind a bunch of turns as he
>as shown in his photo. For more detail on this, see the app notes on
>ferrites on my website.
>
>http://audiosystemsgroup.com/publish
>
>Another point. Mike's common mode choke gets only the common mode trash
>-- that is, the AC line radiating as a long wire antenna. If the RF is
>getting onto the line itself (that is, between hot and neutral), you
>would also need a good line filter. AND -- it must be the right kind of
>line filter, it must be right next to the noise source, and it must be
>bonded (NOT earthed) to the frame of the noise source. By "the right
>kind of filter," I mean that it needs to be configured to block noise
>from the generator to the load, rather than the other way around, and it
>must be designed to be effective over the frequency range that is
>bothering you. In other words, there are line filters, and there are
>line filters.
--
73 de Fred Stevens K2FRD, VO2FS
http://homepage.mac.com/k2frd/K2FRD.html
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