Thanks for the info Richard. It's as I thought, but wasn't exactly sure. I'm waiting on delivery of a NOS HWA-2036-3 supply for my HW-9 & picked-up this "wall-wart" @ our remaining Radio Shack for temporary use. BTW: Nice BIO/photos on your QRZ page. 73 de Steve / W5BIB
Changing the AC "polarity" has no effect on the DC output polarity. Wall-warts usually are fine for QRP rigs. Just get one that has about twice the current rating that what your 5-watter draws key down. 1-amp will work but 2-amps is safer. The 12-volt wall-warts all seem to have the correct DC plug and polarity these days but it can't hurt to check that the center pin is positive.
I cut off the "plug" that it came with. Then checked (with VTVM) & found the "positive" side. I was worried about the "AC" polarity". BTW: I spent a very enjoyable 18 month tour (1965-67) off & on Okinawa @ Torii Station (Hanza) with the ASA 51st SOC & JSPC. I guess that's all changed now....
Not changed very much. The active duty folks and their families love their tours on Okinawa - a tropical vacation courtesy of Uncle Sugar. And the contractors are doing just fine thank you.
Wall Wart + GelCell I have a few gelcells , mostly around 6AH rated and not very big or heavy. I power them at a maintaining current rate from a mid size 12V wallwart that just has a simple halfwave diode rectifier and a filtrer capacitor. (I tore a few failed ones apart to find out) Those wallwarts are rated 12V 800-1000 mA. They have up t0 16 V open load so I use the GelCell to give me a more regulated solid 13V power. I use an automotive tail lamp between the wall wart and the battery, as a current regulator. This makes a fine field supply for QRP radio or auto radio bench supply.
Beware of wall-wart ratings, most unregulated DC output wall warts are rated under load such as 12V/1Amp. At 0 amps, the voltage may raise to 18V or more and can fry your gear. Inexpensive switching power supplies can make a good QRP supply and can often be adjusted to an exact voltage such as the standard 13.8V. I've had good luck with MeanWell switching supplies. Switchers may produce a lot of RF noise, but the modern types are not too bad. Here is an analog power supply that I home-brewed, it's perfect for most 12V QRP rigs: http://www.solorb.com/elect/hamcirc/12V4Asupply/
Ditto on the MeanWell supplies. You can score a 5-amp unit for pretty cheap on FleaBay. Just make sure you have a fuse on the power cable going from the power supply to the radio, just in case...
I was inflating my lawn tractor with my "Tire Slime" portable air compressor and realized it has a 12v output. Soldered the correct power plug and was in business. May be carrying a little extra weight but saved buying a battery and it has a nice handle and charger. Might also come in handy if I have a flat.
This is Exactly why you need a current Regulator that actually limits the voltage into a storage battery. The battery sets a hard voltage limit as it is charging while you u use it to power your QRP rig. The discarded but working wall wart supply, light bulb siries regulator, and 6AH storage battery is a fairly inexpensive and lightweight setup to take into the campground or wilderness.
