Anything need to be considered about regulated power supply for xmtr?

If your new supply meets the minimum voltage and current requirements it should work.

Having said that, I have encountered devices and warts where the voltage was a nominal rating rather than a minimum. One I recall used an internal 12 V regulator (7812 IC) and a "12 V" wall wart. The 7812 type regulators require at least 14VDC to operate and the measured DC from the wart was 15 VDC which is typical no load voltage for a wart. Despite the labeling it provided enough DC voltage for proper operation.

If in doubt, contact Keith at Rangemaster and run it by him.

Neil

This is the perfect place to ask if there are some power supplies that will burn up if they are turned on without a load attached?

Having this notion in mind might relate in the distant past to reports that some audio amplifiers could be harmed by running them without a proper speaker load.

I look very much forward to this discussion.

Carl raises a good point. While anything is possible, the switchers I have encountered either will operate with no load or require a load to operate but I have never seen any which were damaged by no load conditions. Typically PC power supplies need to be run/tested under a minimum load as do some OEM types but if the minimum load is not met they just shut down with no damage. It is a good idea to ask the seller about this regarding a particular supply.

OTOH I have a 12V 36A switcher and a 12V 7A switcher which run all day long with no load without problems. They include over voltage, over current, and over temperature protection and are very reliable.

Neil

"Having this notion in mind might relate in the distant past to reports that some audio amplifiers could be harmed by running them without a proper speaker load."

I haven't run across the problem, but with audio power amps it might make sense because they always operate at power, it's input gain that is controlled.

Also, many TX' require a load, or they could fry.

At one point I thought I'd be "smart" and replace the AC wall wart with a DC unit for my AMT3000 to reduce some minor 60Hz noise. I found it was causing way more 60Hz noise which I could not understand. Eventually I think I found the DC supply was creating a DC offset with the input audio line. I switched back to the AC wall wart and things went back to normal.

I'm not sure I get what your saying..
An AC wallwart outputs a DC current right? I mean, that's what it does, converts the AC to DC.
So the way I see it, the supply would be DC regardless of which of the two sources you mention.
And as for the DC supply, I assume you mean a battery power source?
(I'm really not clear what you're saying)

many TX' require a load, or they could fry.

Ken, it just hit me what you said.
Do you mean if the transmitter is left on, and the audio source is turned off, it could damage the transmitter?

There are regulated power supplies, and then there are regulated power supplies.

The cheaper wall warts tend to generate hum, unless there is decent filtering in the transmitter. Although you can wrap the DC cord around them to reduce the hum somewhat.

When I was experimenting with the Rangemaster, I used a 12 volt brick from a deceased computer.

And even if a power supply says that it's regulated, you need to check it out, by experimentation if necessary. I have several Radio Shack wall warts that claim to be regulated, and they are somewhat, but they still generated some hum (as compared with a true regulated DC power supply that I use for amateur radio).

If the transmitter is on and the antenna load is suddenly disconnected, the frying could occur. Not as much of a problem with the low power stuff that works under part 15, but I've killed two older CB transmitters by keying when the antenna was not connected.

That might be one more reason they call the resistor we connect to the antenna jack for testing and tuning a 'dummy' load 🙂

Oh, I just read SCWIS wrote. That's right. Actually, you don't want have an audio signal when you tune the antenna.

When I was a kid, I also blew a CB transmitter when I tried to talk with a broken antenna connection. Oof!

But that was 5 watts, not .1 watt 😉

Reference was made to power supplies like wall-warts which have some hum. Would it not be possible to add an extra black box along the DC power line to further treat and improve the power quality?

Because we're usually pushing juice into a transmitter, I like to make the black box the transmitter power in point - an extra opportunity to filter out anything that might get picked up by the DC line.

On my Scosche FMT-4 junk-box battery eliminator I used an old cell phone charger because it tested pretty quiet to start with then at the transmitter I added a resistor to drop the voltage to the proper 3 volts (eliminating the two AAA batteries), a small capacitor to filter any remaining line noise and a iron powder toroid of the mix appropriate for 100 MHz+ with several turns of the DC line just before the power connector to keep out any nasties that the DC line might catch between the outlet and the XMTR.