Noisy Guest

[Vito]

Hey y'all, Happy New Year!!

I recently bought a $135 Guest brand 10A (2x5) battery charger. The
raterfratzer generates so much RF that it blanks my child bride's Icom 706
Mk2G on all bands even tho it's on a different power supply! It even
garbages up my 448.475 repeater that has it's own internal supply! Arggggg!

Got any ideas on how to quiet it down? I tried ferrite beads t no avail.

Know of any quite, affordable automatic chargers in the 10A range?

TIA, K3DWW

 

[Shortwave Sportfishing]

I have to turn off the Guest on Lionheart to use HF. It radiates 20
over S9 noise into the Icom M802's insulated backstay. I tried to
make a Faraday shield for it out of tin foil, but it radiates into the
AC line cord so bad it was useless. I can't shield it all the way up
the dock.

You should hear what an Adler-Barbour 12V electronic-controlled fridge
does to Channel 16, the only channel it eats.....with a throbbing,
bzzt-----bzzt------bzzt bzzt bzzt that will drive you NUTS!

73 DE W4CSC
CHARLESTON

I think it's gotta be the switching power supplies - I have the same
problem on my Contender - it is annoying.

I've wondered if building something solid state and cascade the
voltage if that would help the situation any?

Later,

Tom
S. Woodstock, CT

 

[Shortwave Sportfishing]

Any electronics that "switches" is a big transmitter. It generates
harmonic-rich square waves and pulses.

No, actually the solution is quite simple. Go back to the old,
reliable analog chargers that simply put out pulsating DC voltages to
the battery and when you noticed the current dropping off, you turned
the charger off manually or had a saturable reactor that would taper
the charge. The old chargers without the switching electronics we're
in love with, made no radio noise at all......

That's a good point.

Until the transformers go soft. ;>)

Later,

Tom
S. Woodstock, CT

 

[Shortwave Sportfishing]

S'plane to me how transformers "go soft"??

You've been around as long as I have, don't tell me you've never had a
transformer loosen it's windings, or the varnish disintegrate on the
wire causing transformer noise - both RF and mechanical.

Heck, I've got a Astron RS-30a under my desk that is noiser than hell
and has been since I bought it WAY back when. :>)

Later,

Tom
S. Woodstock, CT

 

[Michael Ohlhorst]

Heck, I've got a Astron RS-30a under my desk that is noiser than hell

and has been since I bought it WAY back when. :>)

The noise of an offline switcher could be as loud as these. But this will be
at 10-20 Kilo Herz. The possibilty to vacuum
inject epoxy is the same with standard transformers as with high frequency
switch mode transformers.

michael

 

[Larry]

You've been around as long as I have, don't tell me you've never had a
transformer loosen it's windings, or the varnish disintegrate on the
wire causing transformer noise - both RF and mechanical.

Heck, I've got a Astron RS-30a under my desk that is noiser than hell
and has been since I bought it WAY back when. :>)

No flame intended, but I've been involved with electronics since I was
first licensed in 1954 and can count the number of transformers which have
loosened up on the fingers of one hand! Really, Larry's right - the old
analogue chargers were and are far less noisy.

 

[Shortwave Sportfishing]

~~ snippity doo-da ~~

Junk it. I did mine. If that damned series pass transistor ever
shorts, you can kiss all your equipment hooked to it good bye when the
20-some volts hits them. I don't use analog, series pass regulated
power supplies, here. The ham shack 12V equipment all runs off a bank
of 90-year-old Nickel-Iron cells I got from a demolished Holiday Inn.
They provide about 800AH at 14VDC and are charged by a WalMart
automatic shutoff 10A charger all mounted under the house. This power
supply provides the 120A 14VDC to power my highly-modified TenTec
Hercules II solid state HF linear amp, about 650W OUTPUT. It also
powers all the VHF, scanners, and other 12V toys cluttering up the
desk. It's hooked to a 1KW Tripplite UPS that powers the desk light
and computers/monitors/modems/routers and other network toys in power
outage. The lights in here don't ever blink...(c;

I did something similar when I was really active on the CW bands,
although it is called a Kubota 10 Kw three cylinder diesel generator.
:>)

I live out in the woods (so to speak), last house on the power line
and lose power all the time for a long time, sometimes for days.
Heck, it sneezes outside in the winter and the power will blink.

I will admit it hasn't been bad recently, but I'm not giving up my hot
shower and water when the power goes down. :>)

Later,

Tom
S. Woodstock, CT

 

[Larry]

On Sun, 04 Jan 2004 03:18:07 GMT, Larry W4CSC wrote:

....snip

Junk it. I did mine. If that damned series pass transistor ever
shorts, you can kiss all your equipment hooked to it good bye when the
20-some volts hits them.

You probably know this, but you can (actually, must) prevent that happening
by putting a "crowbar" circuit across the output, after the fuse. This is
just a large scr with a resistor from the bus to the gate with a 14 or 15
volt zener to ground. It doesn't conduct until the voltage exceeds the
zener limit and then the scr shorts to ground, blowing the fuse and
protecting the equipment.

 

[Shortwave Sportfishing]

On Sun, 04 Jan 2004 03:18:07 GMT, Larry W4CSC wrote:

...snip


You probably know this, but you can (actually, must) prevent that happening
by putting a "crowbar" circuit across the output, after the fuse. This is
just a large scr with a resistor from the bus to the gate with a 14 or 15
volt zener to ground. It doesn't conduct until the voltage exceeds the
zener limit and then the scr shorts to ground, blowing the fuse and
protecting the equipment.

Nifty - I think I'll do that. Thanks.

Later,

Tom
S. Woodstock, CT
----------
"We may say of angling as Dr. Boteler said of strawberries:
Doubtless God could have made a better berry, but doubtless
God never did and so, if I might be judge, God never did make
a more calm, quiet, innocent recreation than angling."

Izaak Walton "The Compleat Angler"(1653)

 

[Larry]

Oh, I know. Does it have an output fuse? Mine didn't, just the AC
line.

The Astron 40 I just checked didn't. I added one in series and stuck the
crowbar after it. It does have foldback current limiting, but that won't
necessarily protect equipment connected to it.

 

[WaIIy]

and my previous 12 Honda motorcycles, including the 305 Dream I've
regretted selling since the 60's!

Boy, those Honda Dreams were the envy of every guy in the neighborhood.
Heck, I was happy with my Whizzer, though.

 

[Larry]

Foldback current limiting assumes the pass transistor doing the
folding back is a functional device, not welded from E to C....(c;

Good point!