[aprssig] Quieting Honda Generator (was) Portable Ops from 12vvia 115 VAC

[Ray McKnight]

I've been doing a lot of generator research myself.
Something interesting you might not be aware of, is
That almost all of these smaller generators do not
Operate in the traditional manner, producing 120vAC
Directly by turning a generating coil.  The generators
You are talking about actually produce 12vDC, then feed
This to a DC-AC inverter to get 120vAC.  So the noise
You are experiencing on the AC output is most likely due
To the inverter, and I would suspect most of these inverters
Are not true sine-wave inverters (the Honda 2000-watt seems
To be though because it is marketed for use with "sensitive
Electronic equipment").  I would suspect that many produce
A modified square wave, and are therefore very likely to
Cause problems with some types of equipment (especially
Things requiring a good sine wave for timing purposes, and
Some laptop power supplies don't seem to like it much either).
If your generator has a 12vDC outlet (and isn't electric start!)
It probably falls into this category.

For my money, I never operate any electronics directly off
Generator power, I always have a UPS to protect it.  One way
You might eliminate your "noise" is by trying a good UPS with
Isolation or preferably even an "inline" UPS like used on 
Computer servers which always supply AC from the UPS's inverter
(which is a high-quality sine wave output).  But be aware that
most small, consumer-grade UPS's offer no line isolation or filtering.

If you've got a scope, take a look at the power produced by the generator
and you'll probably be surprised.  If you actually need or can easily use
12vDC, maybe you can just pull that off your Honda and eliminate its
inverter problems altogether.  Just a thought.

-----Original Message-----
From: aprssig-bounces at lists.tapr.org [mailto:aprssig-bounces at lists.tapr.org]
On Behalf Of J. Gary Bender, WS5N
Sent: Friday, December 31, 2004 17:06
To: TAPR APRS Mailing List
Subject: Re: [aprssig] Quieting Honda Generator (was) Portable Ops from
12vvia 115 VAC

For those following this sub-thread, I got a direct reply from Jim, W6RMK, 
pointing me to:
http://www.dellroy.com/W4EF's-Ham-Radio-Page/Portable_Operation/EU2000i_
Filter.htm

The article describes a common mode filter for the AC output that did 
the trick with the 2 KW Honda generator.  Looks like the same problem I 
am having with the EU1000.  The noise seems to be on the AC line but not 
radiating from the generator.  I.e., unplug the AC cord and the noise 
goes away.

I will also try using the generator's 12 VDC output directly to the 
battery when I am hamming rather than plugging the camper into the 120 
VAC output.
--
Gary, WS5N


On Fri, 31 Dec 2004 09:37:17 -0700, J. Gary Bender, WS5N wrote:
> I have the 1KW Honda generator in use on my camper.  I love it in that
> it starts easily, has a handy 12 VDC charging output, and runs all night
> on the load of the furnace even on very cold nights.  However, it also
> wipes out reception on my 3-22 MHz SW receiver, and does a number on AM
> broadcast as well.  It covers the bands with birdies.  FM seems to be ok.
> 
> I have not tried it yet with an HF rig, but my guess is that the
> generator will only be useful for recharging batteries between operating
> periods.  Has anyone had any experience using these generators with HF
> gear?  Have you found ways to suppress RFI?  Are you limited to VHF and
> above while it is running?  I guess something easy to try would be a
> 100' extension cord and seeing how it behaves with physical separation
> from the radios. -- J. Gary Bender, WS5N Tijeras, New Mexico USA
> 




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