Next message: Philip J. Rosch: "lv-ab: FW: Katama Anchorage Restrictions"
As more people begin to use e.mail over SSB, they will find out what I have.
Almost everything electric or electronic interferes with the SSB reception.
To compound that, SSB transmission disables my autopilot and messes with the
laptop touch pad. Items that interfere: Autopilot (general hash AND morse
code like signal on 12.359 (herb)), GPS, laptop 12V power cord, depth
sounder, cheapie inverter, fans, wiper motors, small amount from engine
alternator.
The only clean items are the Standard VHF & older Furuno radar. I basically
need to heave to and shut down to send e.mail. Listening to Herb's weather
transmissions, being in the middle of the cruising day and lasting hours, is
not practical for me, as I cannot navigate at the same time.
Lee Haefele
Subject: RE: lv-ab: Inverters... pure sine or modified?
> Brian Stewart wrote:
>
> James
> Interesting comments. I have a number of modified and one pure sine wave
> inverter aboard. I'll run a number RF noise tests this weekend when we
> get back aboard. May be the reason I still get a bit of noise at 14 MHz.
> By the way the pure sine wave unit is the only way to power a computer
> and speaker system if you plan on attaching a separate sound system to
> it... It totally eliminates the hum that comes with using a modified
> inverter.
> --
> Brian Stewart
> Pilgrim
> Whitby 42 #304
> VB8320 VA3PIL
>
>
>
> REPLY
> While I was still employed at Xantrex, we ran some tests on 1000 watt
> inverters, one MSW Prowatt and one Prosine.
>
> The tests were conducted by some radio amateur operators with access to
lab
> quality spectrum analyzers and so one.
> The amount of noise and RFI radiated by the Prowatt was terible.
> It effectively cancelled low frequency communications on the marine SSB
> bands over any distance.
> Not to mention a lot of ham bands. Weak signals were simply drowened out.
>
> For those who do not use ham radio, remember that Differential GPS also
> relies on a low frequency broadcast channel.
> And if you still like ot use Loran, the 100Khz carrier really ges
clobbered.
>
> And then of course you have all those other electronic toys that are
> sensitive to harmonics generated by quasi sine wave inverters. The
amountof
> harmonics is proportional to how sharp the rise time is.
> Sharper ( faster ) rise time of the waveform means more harmonics.
>
> This is why MSW inverters cause induction motors to run hotter than
normal
> and thus shorten their service life.
> But if you change appliances every few yeas who cares!
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