"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:


It's Mark!

Hi there. Hope things are going well for you. Hey, I have a bad back too
unfortunately. Can't really do anything for many bad backs except meds.


I've been quite busy lately with various things including the new telescope, and
I've taken on another volunteer gig teaching astronomy to four classes of 8th
graders at an inner city school.

Most of the ones on Ebay are your RS or SL models. Mainly linear supplies.
Plus, I'm not looking to drop more then $50 on one really. So for me right
now I'll just go with any good deal. I saw a couple switchers last week
though.


I still like linear supplies - mostly because I can usually figure out how to
fix them if they break. A nice thing about ebay is odds are another one will
turn up in a week or two.

snip
Good to hear from you Mark. It's always a pleasure reading your comments.
Hope our backs feel better.


Actually, I've got my back pretty well under control, but it took some lifestyle
changes, replacing my mattresses and just about every chair I normally sit on.

If you contact me direct I may be able to give you some pointers on your back.

Regards,

Mark



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.

wrote in message
oups.com...
"Lucky" Wrote (in part):
Does anyone know if Motorola makes a couple models for Astron? I see
two or so Astrons on Ebay that are also refered to as "This Astron
model is also
Motorola part #1394A" and other part numbers. I saw one vendor who
sold all Motorola equipment but he had 2 of the Astron's that were
mentioned with
Motorola in some Ebay ads.

They had Astron's name on them but funny a Motorola dealer has them as
part of his inventory. Anyone know anything? {about the PSU's :) :)

snip

Thanks
Lucky
------------------------------
You have it backwards, Astron makes(?made?) them for Motorola.
They are just as good as normal Astrons.

Terry


Yes Terry

that Motorola dealer wrote me and told me that also. BTW, I finally bought a
"new in Box" Astron SL-11a for $45 off Ebay. Looks good and I think 7 Amps
Cont. is enough for me right now. What do you guys think of it?

Lucky

Lucky wrote:

wrote in message
oups.com...
"Lucky" Wrote (in part):
Does anyone know if Motorola makes a couple models for Astron? I see
two or so Astrons on Ebay that are also refered to as "This Astron
model is also
Motorola part #1394A" and other part numbers. I saw one vendor who
sold all Motorola equipment but he had 2 of the Astron's that were
mentioned with
Motorola in some Ebay ads.

They had Astron's name on them but funny a Motorola dealer has them as
part of his inventory. Anyone know anything? {about the PSU's :) :)

snip

Thanks
Lucky
------------------------------
You have it backwards, Astron makes(?made?) them for Motorola.
They are just as good as normal Astrons.

Terry


Yes Terry

that Motorola dealer wrote me and told me that also. BTW, I finally bought a
"new in Box" Astron SL-11a for $45 off Ebay. Looks good and I think 7 Amps
Cont. is enough for me right now. What do you guys think of it?

Lucky

Personally, I'd rather have one with meters, but 7 amps is probably more than
enough unless you're looking to run several receivers at once or take up arc
welding as a hobby.

Otherwise, as far as I know, Astron has a reputation for making good quality
power supplies.

Lucky wrote:

Yes Terry

that Motorola dealer wrote me and told me that also. BTW, I finally bought a
"new in Box" Astron SL-11a for $45 off Ebay. Looks good and I think 7 Amps
Cont. is enough for me right now. What do you guys think of it?

Lucky

It will serve you well for decades.

I am not a big fan of MOV over voltage protectors,
but it might be well worth the few dollars it will
take to add on between the Astron and the wall outlet.

Terry

All of the Astron supplies that Ihave sen have the power switch in the
primary,so when it it turned off there is no current being drawn.

In my situation I have radios that stay on all f the time, so my
power supply is almost never switched off. Lambda supplies
don't have a pwoer switch so I have to unplug them to turn them off.

Thenice thing about a MOV or other over voltage protector, is it
will help tostop any line spikes from getting tot he power supply.
I use a non MOV style,a Zero Surge, but MOV based units are
much more common and can realy save you supply.

I have my "radio desk", a PC "L" desk in fact, wired with a
DPDT magnetic breaker so I can flip one "switch" and remove
connection with both sides of the AC mains. I have another
breaker for the standby gell cells so so with one hand I can
knock my entire system down. Likely over kill, but I wanted
something that was easy and fast to kill all power in case
something goes wrong.

Terry

First appreciate what the MOVs do. A transient coming down
black wire is shunted by MOV to all other wires. Now a
transient, seeking earth ground, has more paths to find earth,
destructively, via the adjacent appliance. Protection is
located in earthing; not inside a plug-in protector. An MOV
is effective if connected short from each utility wire to
earth ground. This is why 'whole house' protectors are so
effective and why plug-in protectors can even contribute to
damage of the adjacent appliance.

These concepts are often discussed in the newsgroup
rec.radio.amateur.antenna. Some protection systems use
MOVs. Some require no MOVs. But in every protection
'system', only one component that is always required. Earth
ground. Plug-in protector have no such earthing connection -
so they avoid the entire topic. Plug-in protector provide no
effective protection, so are even undersized - too few joules
sold overpriced.

MOVs are shunt mode protectors. Another type is series
mode. Series mode protectors will supplement a protection
'system'. A series mode protector alone must stop, block, or
absorb what three miles of sky could not. Will not happen.
Series mode protectors alone must act like a dam.
Insufficient. Series mode protectors used in conjunction with
a 'whole house' protector will act like a dike. Now we are
talking effective protection. Series mode protectors are
sold by Zerosurge, Surgex, and Brickwall. They can supplement
the primary and secondary protection 'systems'.

Notice that safety ground wire that bypasses a series mode
protector. So the Zerosurge, et al block a black (hot) or
white (neutral) wire transient that simply enters electronics
via the direct green (safety ground) wire. Where is the
protection? Just another reason why series mode protectors
can only be part of a protection 'system'.

'Whole house' protectors being so inexpensive and so
effective that the telco even installs one on your incoming
telephone line - for free. Notice what that telco protector
connects to? Earth ground. A protector is only as effective
as its earth ground.

Lucky wrote:
wrote in message
oups.com...
I am not a big fan of MOV over voltage protectors,
but it might be well worth the few dollars it will
take to add on between the Astron and the wall outlet.
Terry

Hi Terry
I was wondering about that. I've been using a surge protector all this time.
Can't hurt to plug the Astron into it right? With wall worts and other radio
PSU's, they tell you to unplug them so they last longer. I mean they still
are warm even if the radio is turned off.

Does it work that way with the Astrons? Even if you turn it off it's still
drawing some current and stays warm to some degree? Should I turn off the
surge protector or unplug it when not in use?

Lucky