Wellbrook Mag Loop antenna at Mark Fahey’s QTH near Sydney, Australia.
Many thanks to SWLing Post contributor, David Goren, who writes:
I need a new power supply for one of my Wellbrook loop antennas.
Do you know of good source for reliable ones? I forgot where I obtained the last replacement which worked fine until the wire attaching to the plug worked loose.
Here are the specs:
Plug in Class 2 Transformer
Model: DC1200300R
Input: 120VAC 60 Hz 9W
Output: 12V DC 300mA
manufacturer: Sandin Ltd.Searching online delivers a mixed bag of somebody’s old power supply.
Post Readers: Any suggestions for David? I’m sure he’s particularly interested in a good quality power supply–one that’s quiet and would last a few years. Please comment and include links when possible!
Try the folks over at Bioenno Power They are very radio enthusiast friendly
https://www.bioennopower.com
I use a used Astron RS-4A, which is overkill but the only thing i could find that was not noisy. If you can find a genuine Sangean AC adapter used for the HDR-18 model, that would be cheaper and almost as good.
Condor makes excellent linear power supplies. I have a 12v 3.4 A Condor PS that feeds a Wellbrook ALA100M antenna interface, a MFJ 1026 noise canceller and a Winradio G33DDC.
Why do not you build one yourself? Quite easy, some diodes a couple of capacitors and if you want a cheap LM7812 voltaje regulator. There are plenty of schemes on the web.
Here is a website that sells interesting linear adapters:
https://www.poweradapter.co/adapters-linear-ac-adapters-c-78_101.html?zenid=uegocq95euecc0ti8pav7hdr81
Andrew (from Wellbrook) recommends a specific Jameco power supply (I’ll try to find the link). He stated that certain import/export regulations (in Europe and the States) require him to use the power supply included with all orders. He would like to use a better power supply but is only following regulations. I use a Talentcell 8300mAh lithium ion power pack (~$30.00) to supply my Wellbrook LNP and Eton E1XM. At a modest volume, I can generally get 14-15 hours on a charge. Removing all AC power has reduced noise immensely. Plus, I can go mobile in a few minutes for a dxpedition.
My Wellbrook supplied adapter failed miserably after a year. It would actually transmit the interference through the antenna broadcasting it for a block in all directions. I replaced It with a JAMECO RELIAPRO AC to DC Power Supply Wall Adapter Transformer Single Output 12 Volt 1 Amp 12 Watt. I’ve never had problem since.
Perhaps it won’t help much if you’re in the US, but here in Oz there’s a 12V 300mA Linear power supply (ie not switch mode) available from a local supplier:
https://www.minikits.com.au/DCA300-12PM
Jameco in California is where i got mine from.
Consider a bench supply like a Pyramid PS8KX. $35 bucks at Walmart plus shipping. I run my Wellbrook, a DX Engineering Amplified Vertical, and an Elad ASA042 from a smaller Pyramid supply (PS4KX) and there are amps to spare. Flip one switch and everything lights up.
https://www.walmart.com/ip/Pyramid-Bench-Power-Supply-AC-to-DC-Power-Converter-6-0-Amp-Power-Supply-PS8KX/28501893?wmlspartner=wlpa&selectedSellerId=0
Ron Hunsicker
^This, even if a Pyramid or similar affordable brand. Unless going off-grid with batteries, a linear and regulated power supply is the way to go for preamps IMO.
A dedicated linear regulated power supply is a good investment when factored against its likely many years of viable service.
I have an older Pyramid version similar to Ron’s Wally World link. Other than once blowing a regulator, which was a quick fix, it has provided like 20+ years of good service so far.
Just cut the wire where it feels like it broke (flex backwards and forwards to feel where it is – it probably failed right up against the strain relief). Check the polarity on the PSU label (normally +ve to center). Strip back and fit a new coaxial ‘barrel’ DC connector. If it must be waterproof, fill the gaps between the wires and the screw-on barrel after soldering. You can use Ace Hardware part number 12589 (https://www.acehardware.com/departments/paint-and-supplies/caulk-and-sealants/caulk/12589) if in the USA – this goes on white and dries clear so that you can see where it went.
How about a small sealed gellcell battery used in security systems in homes?
They are 12v and can easily be recharged.
Lowes’ sells them.