Power supply question

[arajca]

I'm looking at power supplies and I've found a nice, compact 30A power supply for CCTV systems. Would these generally by usable with radio communications?

Also, anyone have experience using a computer power supply to power a radio? I've seen many have 10+A 12 V outputs.

[Airrace]

They will work fine as long as the voltage is what you need for the device.

[tinker]

a nice, compact 30A power supply

Thirty amps is a lot.  That will be one heavy power supply and capable of much more than a typical VHF comm radio needs.

using a computer power supply to power a radio?

Something like that will probably work.  Be sure to pay attention to ventilation if you decide to package it up somehow.

After you verify the PS voltage, I'd measure the current the radio uses while transmitting (that's the biggest draw), then shoot for a supply that is rated at maybe 150% of that current.  My choice would be to hunt for a suitable laptop brick power supply since they are already nicely packaged and portable.

If you don't have an ammeter and you intend to fool with this stuff, I'd suggest something like http://www.mcmelectronics.com/product/72-7765  Good meters are ridiculously cheap these days and MCM always seems to have something on sale besides.

[arajca]

Thanks for the info. I have nice Fluke at work.

Currently, I have an Astron SS-30 the I'm using for my radio box (see other thread - update later tonight...). It will power three radios - I'm using the 10A fuse for each to total my needs.

I'm looking at options for another box with an airband and uhf liaison radio or two.

[SarDragon]

I would recommend not using a computer PS for a radio, unless you change the parallel small gage wires for single larger gage wires. This will prevent possible ground loops, and other potential interference.

Most laptop bricks I've encountered have higher voltage and lower current capacity than you would need on a mobile radio.

[tinker]

I would recommend not using a computer PS for a radio, unless you change the parallel small gage wires for single larger gage wires. This will prevent possible ground loops, and other potential interference.

With all due respect, I think you have been seriously overexposed to Monster Cable advertising.  This is nonsense.  Ohm's law is the only thing that applies.

[SarDragon]

Monster Cable? Don't think so. In fact, IIRC, they preach many little wires instead of one fat one, contrary to my proposition.

There's more than Ohm's Law at work here, which, BTW, I learned when I was about 10 or so. Parallel power paths increase the possibility for interference from stray currents, which is not a desirable thing in radios.

I didn't say it wouldn't work, I just provided an idea to make it work better.

And again, YMMV.

[tinker]

Parallel power paths increase the possibility for interference from stray currents

Wow.

I have no desire to pick a personal fight with you, but I also think that nonsense needs to be identified as such so that the unwary, arriving via Google, are not taken in.

Maybe I'll go at it this way, and make it my last post:  I held a General class amateur license when I was in junior high, earned a commercial First Class Radiotelephone license when I was in high school, and eventually received a master's degree in electrical engineering.  During high school, college, and graduate school I worked as an electronic technician, primarily with HF, VHF, and broadcast radio equipment.  I installed and commissioned a 5KW AM transmitter and a 100KW (ERP) FM transmitter.  I worked and wired broadcast and recording studio control rooms.  I hold three or four patents and have been principal or sole author on several papers published in refereed electronics journals.  Based on my training and experience, it is my opinion that your statements are total nonsense.

BTW "parallel small gage wires" are generally referred to as "stranded" and "single larger gage wires" are generally referred to as "solid."  And the correct spelling is "gauge."  Ref http://en.wikipedia.org/wiki/American_wire_gauge

[SarDragon]

Taken to PM.

Let us now get back to providing assistance.

[billford1]

I have worked in electronics engineering for most of the last 20 years.  Please let me suggest that you do the easy thing and buy a power supply that is designed for the load, continuous power output specifications and noise immunity requirements that CAP VHF Radios have.   It takes a lot of time and money to reverse engineer use of an electrical design that was developed for a different application.  If you take a computer power supply and  kluge together a power supply box to drive your CAP radio it may work. There may however be an unseen outcome that could result in electric shock or at the least your power supply might just quit.  If it were me, I would consult the Wing DC and the folks at NTC.  Hope this helps.

[wuzafuzz]

Parallel power paths increase the possibility for interference from stray currents

Wow.

I have no desire to pick a personal fight with you, but I also think that nonsense needs to be identified as such so that the unwary, arriving via Google, are not taken in.

... Based on my training and experience, it is my opinion that your statements are total nonsense.

Wow is right.  Interesting way NOT to pick a fight.  I'm reminded of Ricky Bobby prefacing insults by saying "with all due respect."   

[SarDragon]

Thanks for the support, but I've taken it to PM. Let's not derail this any farther.