"Ron Hardin" wrote in message
...
I run everything off a SS-18 (R8B and 30 ANC4's DA100E's and DSP's). I
tried
a RS-7A but didn't like the heat it throws off. The switching supply
avoids
that.

I fuse the output at the supply with an inline fuse (reflecting the wire
gauge), and fuse each device separately with like 1/4 or 1/2 or 1-2 amp
fuses
where I distribute 12v to them all. A properly working power supply can
easily
burn up the light wires running to these things if you don't fuse it,
where
the internal resistance of wall warts had prevented it before you went to
a central power supply.

There's some birdies from the SS-18 but they're not bad; and I put the
thing
in the basement and run the 12v to the first floor, so there's some
distance
intervening as well. It does run enormously cooler.

I was motivated to get the central 12v by the heat the R8B's supply throws
off, that is now eliminated, as well as the growing number of wall warts
I was accumulating as I added to my phased array.
--
Ron Hardin


On the internet, nobody knows you're a jerk.

Hi Ron

I heard switching supplies are not the best choice for radios. But I don't
know enough about them to really know. So you're putting fuses on the hot
wire {+}coming off the PSU to the radio??

Lucky

Lucky wrote:
I heard switching supplies are not the best choice for radios. But I don't
know enough about them to really know. So you're putting fuses on the hot
wire {+}coming off the PSU to the radio??

I put a fuse on the hot wire, with amps based on the carrying capacity of the wire
(not the capacity of the power supply!).

The wire goes upstairs from the basement, and at the upstairs end I run it into
many fuse blocks, each with tiny fuses (1/4 to 2a) for each of the devices I
power with it, depending on its needs. The wires that typically run into coaxial
power plugs have very little capacity before overheating, and you want its fuse
to blow before it (the particular wire) heats up.

So no short anywhere heats up any wire.

A normally functioning power supply is quite capable of burning down the house
if run into typical hookup wire without some fusing.

It's unintuitive because the same wire works fine at 120v, but it's amps that
causes heating, not power, and there's ten times more amps (=100 times more heating)
at 12v than 120v.

--
Ron Hardin


On the internet, nobody knows you're a jerk.

Ron, What gauge wire do you use to run the DC upstairs?
I have some heavy silicon jacketed welding cable that I have
considered using if I ever get around to building a real exteranal
battery "bank". The main killer with normal wire is the heavy IR
losses. 0.5 V at 12V is a killer.

I occasionaly, at rare moments mainly during T-storms, actually use
my ham gear to talk. 8A max for 2mtr, about 10A on voice peaks for
SSB. The rest of the time I draw less then 5 amp with every +12V
device in the shack on. Which isn't all that often.

I have an 15A magnetic breaker on each gell cell. And individual
breakers sized to meet the normal current demands per device.
I have a 6A meter, that only monitors the non ham gear. For most of
my devices I use 2A mag breakers. This allows me to rapidly power
down entire sections. The R2000s draw about 150mA each even when
off for the clock, by switching off the +12V I avoid sneak devices that

might use juice even when off. My 12Amp supply is slighlty overloaded
on voice peaks, but Lambda underates their supplies. It will deliver 16
Amps for 20 minutes before it goes into thermal fold over.

I have 2 clocks, on a 24Hr clock I built based on an early LSI (5314)
chip with a built in backup/keep alive 9V nicad. My other clock is from
my
1981 Subrau that we drove to death. The frame rusted through. Both
clocks dfrasw abut 50mA with the display on, and less then 1mA
displays blanked. A much better power load then the R2000s.

I have based my design on what I saw in a military comm center.
I have a 12A and a spare ready to turn on 12A, and my older 8A
supply in the bottom of the closet. I bought all the parts surplus for
less then pennies on the dollar. All told I have no more then $100
in my entire power system. And that inlcudes the PV arrays, gell cells,

everything.

As I mentioned before I have found the canon/amphenol 4 pin XLR
connectors to be great, safe for 12V DC. The broadcast industry
ony uses pins 1 and 4, I added 2 and 3 (1&2 and 3&4) this halves the IR
losses, doubles the current from ~10 to 20. Each of the power loads,
IC28A, HTX100 gettheir own XLR, the receive section has it's own 4 pin
XLR that feeds a set of individually protected 5.5/2.1 coaxial power
connectors. Presently I have 5 more scokets then devices. I mounted
them on a piece of angle alumium and run male to male coaxial power
cords. Makes changing things pretty simple. Each breaker is labeled
to help avoid confussion. Sounds a lot more complex then it realy is.
I try to only get gear that will work directly on +12V. But sometimes a

good deal on "odd" powered radios like the DX398 come along, so I
use LM117 to reduce the voltage. When ever I can I build the regulator
in the device.

I added several "cigerette lighter" sockets because it is handy to be
able to power up things like cell phone chargers froma clan DC source.

I also added a 20 Amp mag breaker, both + and - to switch to an
external power source like an automoble.

Again this all sounds much fancier then it really is. Back in 1974 I
learned
to not depend on the public power company. The tornados that came
through on April 3 that year knocked out power for several days. And
my all of my radio gear required 120V AC. I decided then and there,
sitting in the dark that the next time the lights went out I would
still be
able to listen.

31 years later I think I have suceeded fairly well.

Terry

wrote:

Ron, What gauge wire do you use to run the DC upstairs?

Just regular 16ga zipcord. I'm not running anything much on it.

--
Ron Hardin


On the internet, nobody knows you're a jerk.

"Ron Hardin" wrote in message
...
Lucky wrote:
I heard switching supplies are not the best choice for radios. But I
don't
know enough about them to really know. So you're putting fuses on the hot
wire {+}coming off the PSU to the radio??

I put a fuse on the hot wire, with amps based on the carrying capacity of
the wire
(not the capacity of the power supply!).

The wire goes upstairs from the basement, and at the upstairs end I run it
into
many fuse blocks, each with tiny fuses (1/4 to 2a) for each of the devices
I
power with it, depending on its needs. The wires that typically run into
coaxial
power plugs have very little capacity before overheating, and you want its
fuse
to blow before it (the particular wire) heats up.

So no short anywhere heats up any wire.

A normally functioning power supply is quite capable of burning down the
house
if run into typical hookup wire without some fusing.

It's unintuitive because the same wire works fine at 120v, but it's amps
that
causes heating, not power, and there's ten times more amps (=100 times
more heating)
at 12v than 120v.

--
Ron Hardin


On the internet, nobody knows you're a jerk.

Ron,

what capacity fuse should I buy for the usual wires that come with the power
adapter tips at Radio Shack if I want to "Hot Guard" the output wires to
power radios like you did? How can I find out it's carrying capacity? Is
1/4 A good?
I think they sell wires with fuse holdes on them right?

Thanks
Lucky

Lucky wrote:
Ron,

what capacity fuse should I buy for the usual wires that come with the power
adapter tips at Radio Shack if I want to "Hot Guard" the output wires to
power radios like you did? How can I find out it's carrying capacity? Is
1/4 A good?
I think they sell wires with fuse holdes on them right?

I fuse the individual device wires for the device's claimed needs, more or less
times two. If it says 500ma, use a 1a (quick blow) fuse.

I got a bunch of 6-fuse fuse blocks (automotive, I guess) and wire all of one
side to +12v, and attach the device + wires to the other side. Radio Shack has
4-fuse blocks. I'd really like 20-fuse blocks already wired together on one
side but haven't found any.

The 16ga zipcord is fused with an inline fuse (quick blow) at I think 7a.

Use quick-blow fuses because slow-blow fuses get very hot themselves without
blowing. If a device blows a fuse in normal use, just use the next size bigger
fuse.

Acc. to what I can find on the web, 16ga wire is good for 10a, or 13a, depending
on who you believe, and also that's an AC rating and who knows what that means
at DC. Anyway somebody believes that's acceptable heating. Every 3 wire gauges
thinner gives you 2x the heating.

--
Ron Hardin


On the internet, nobody knows you're a jerk.

Lucky wrote:
I heard switching supplies are not the best choice for radios. But I don't
know enough about them to really know.

They're usually not much good right next to the antenna (or the radio, if
the antenna is on the radio), but vary in how bad the birdies they generate
are. My MFJ puts out enormous birdies so I'd avoid their switching supplies.
My Astron SS-18 is tolerably low. The payoff is that the switching supplies
generate much, much less heat, and thus use less power if left on all the time,
in particular.
--
Ron Hardin


On the internet, nobody knows you're a jerk.

In article ,
Ron Hardin wrote:

Snip

The payoff is that the switching supplies generate much, much less
heat, and thus use less power if left on all the time, in particular.

Linear supplies are usually around 65% to 70% where switchers are often
80% to 90% range.

--
Telamon
Ventura, California

Lucky wrote:

Hi Ron

I heard switching supplies are not the best choice for radios. But I
don't
know enough about them to really know. So you're putting fuses on the
hot
wire {+}coming off the PSU to the radio??

Lucky
---------------------------------------------
They may have improved swith mode power supplies in the last
few years. But my experience has been that they produce a LOT
of RF noise. Sinc ethe local RF noise almost always set the limits
for reception, you can't receive singals lower then the locla noise
floor,
it is weel worth the erffort to keep my house as RF "clean" as I can.

And using a switch mode to power my radio gear is at odds with
receiving weak signals. I have friends who use switchnmode supplies,
and mounted them in faraday cages with extensive fitlering for the AC
mains and DC output. Even a well built linear/analog supply can need
some additional bypass caps to really quiten it down.

If I were going to use a switch mode, I would be sure to have an
arrangement to retrun it if it was too noisy.

Another point for me is linear supplies will last much longer due to
their passive nature. Switch mode supplies have electronic switches,
ether bipolar or FET transistors that fail with suprising regularitly.
At the
electronic facility where I work, we have linear supplies that are over

30 years old. None of the switchers last any where near that long. And
anyone can repair a linear supply if it fails, switchmode supplies are
much more complex and when they fail are very dificult to repair.

Terry

wrote in message
ups.com...
Lucky wrote:

Hi Ron

I heard switching supplies are not the best choice for radios. But I
don't
know enough about them to really know. So you're putting fuses on the
hot
wire {+}coming off the PSU to the radio??

Lucky
---------------------------------------------
They may have improved swith mode power supplies in the last
few years. But my experience has been that they produce a LOT
of RF noise. Sinc ethe local RF noise almost always set the limits
for reception, you can't receive singals lower then the locla noise
floor,
it is weel worth the erffort to keep my house as RF "clean" as I can.

And using a switch mode to power my radio gear is at odds with
receiving weak signals. I have friends who use switchnmode supplies,
and mounted them in faraday cages with extensive fitlering for the AC
mains and DC output. Even a well built linear/analog supply can need
some additional bypass caps to really quiten it down.

If I were going to use a switch mode, I would be sure to have an
arrangement to retrun it if it was too noisy.

Another point for me is linear supplies will last much longer due to
their passive nature. Switch mode supplies have electronic switches,
ether bipolar or FET transistors that fail with suprising regularitly.
At the
electronic facility where I work, we have linear supplies that are over

30 years old. None of the switchers last any where near that long. And
anyone can repair a linear supply if it fails, switchmode supplies are
much more complex and when they fail are very dificult to repair.

Terry


Good morning Terry.

Based your real world experiences, it sounds better to stick with linear
PSUs for now at least for me. I don't have the know how Ron has to make sure
it all works right with a switching PSU if there is any added problems. I
like to eliminate any potential problems that might occur if I have a
choice. I just want to listen to the radio, not build faraday cages

Lucky