On Sep 20, 2020, at 12:10 PM, Kimo Chun <kimochun@gmail.com> wrote:
All good advice. It is safe to assume that virtually all inverter
generators generate rfi noise. It is safe to assume that the bulk of their
market/customer doesn't care about or need clean outputs so they don't
care
either. I used to have one of the last generation of completely shrouded
conventional Honda generators EX3300. It was stolen. I wish I had it now.
Honda doesn't make them anymore. Too bad.
Though I have not tested newer delivered models, the original EU1000 and
larger models all generate RFI. It was more prevalent/noticeable on lower
frequency bands, say 20m and lower. I have one EU1000 that was modified by
a top notch engineer/ham friend to minimize this. I don't have the details
nor have I taken it apart to learn what was done. I just bought it off him
as he was moving. We've successfully used homebrew inline common mode
chokes using Type 31 cores on AC extensions leaving the generators that
have worked OK. No, I didn't do measurement tests (I could) but it was
fine
for our Field Day operations. For a fixed, longer term situation more
testing would be in order. A friend bought a Honda 7kw model that had the
same problem. I don't know if he was similarly successful. I didn't follow
up.
If you want to circumvent this issue purchase a conventional generator and
stay away from inverter types. Otherwise, be prepared to clean it up
yourself.
The other issue people don't pay attention to is generator design and
application. None of the typical home power backup generators (Generac,
etc.) offered are for continuous - off grid use. You can use them for some
hours per day or perhaps for a few days (see their instructions) at a
time. If you are looking for near continuous power after a hurricane for
possibly a few weeks (your fuel problem notwithstanding) you need a much
better, different generator designed for that. It will often run at lower
RPM and have other heavy duty design features which require significant
monitoring and maintenance.
Or use their commonly sold one and pray and accept their failure. Say,
purchase a new one after each major use, assuming it did last through that
event. Perhaps a viable risk.
73, Aloha
Kimo Chun KH7U
Date: Sun, 20 Sep 2020 06:46:45 -0700
From: Dave Cole <dave@nk7z.net>
To: rfi@contesting.com
Subject: Re: [RFI] Inverters?
Message-ID: <58123b6c-8262-97ab-1929-dfb0c78f0b51@nk7z.net>
Content-Type: text/plain; charset=utf-8; format=flowed
The best test is to bring a portable shortwave radio, and listen before
you buy... Most places, have a demo generator set up.Make it clear to
the vendor that if the unit is generating RFI you will be returning it,
with the expectation of a full refund.
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources
On 9/19/20 9:23 PM, Warren Wolff via RFI wrote:
? I am considering the purchase of an emergency back-upgenerator.? For
the first time, I have encountered unitstagged as ?inverters?.? Does this
mean that some systemsare AC generators while the ?Inverter-types?
generateDC and then convert it to AC?? ? ?Inverter?
immediatelyprecipitates
the worry of RFI.? Comments, please.
WarrenW7WY
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