Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Paint can dummy load?

Cheech

Cheech

Active Member
Apr 6, 2005
716
6
28
35
Medina county Ohio
Ok I was looking through my friend "Now your talking" book today and noticed it showed a dummy load constructed of a paint can containing resistors. They showed it taken apart but it had no oil in it. The lid of the can had the SO239 conector and the board with the resitors. I am interested in building one of theese and wondered if anyone has done so? Also any other info would be great. Thanks! ;)
 

I have one I made in the eraly 90's. Uses a quart sized can, high wattage resistor array, filled with mineral oil. SO-239 needs to be sealed with caulk to eliminate oil from seeping out. Lid is soldered shut to the can as well. Conservatively rated for 100w.
 
Look around for a real "Cantenna" by Heathkit, you can find them cheap and they hold 2000 watts (if you need that much)

BTW: DO NOT FILL IT WITH MOTOR OIL, :LOL: , I know somebody who did. Did you know that motor oil vapors are flammable?

.
 
Motor oil hehe not good! I was thinking it would lead to a fire :shock: Ill take look around and see if I can find one of those cantennas. They sound good, and as for the 2000 watts thats a big nada! I can hardly run 350 hehe. :shock: :LOL:
 
Motor oil-- I don't know but I fill mine with mineral oil-- unless you can find transformer oil around and want to deal with PCB's--- But anyhow they are real easy to make-- a connector, resistors and mineal oil and some sort of paint can
You can actually use it without any mineral oil but at lower wattages
But thats all you need is a bunch of resistor to turn the RF into heat (@50 ohm impediance total) and a way to connect them to your coax-- thats it instant dummy load-- there is a local int he area that has a dummy load with just resistors mounted on perf board-- he uses low power so its good for him
Its a cool project and they work pretty good too-- definatly worth the time to build one up if you don't have a dummy load that can take any real power
Definatly worth building or buying an old Heath
 
Worth looking into for 20 bucks-- they sure do last
Not sure how much power your into running but its worth getting and for 20 bucks you can't even buy the parts to build one for 20 bucks
Anyhow-- buy it if you can-- but personaaly homebrewing is my thing and you might enjoy making one
If you build one, I've heard one person say you CANNOT use wire wound resistors and other say that they do work OK-- I would'nt use them unless you have a bunch of wirewound laying around then its worth a try
 
Yeah I may build one but if I can come acrost one for cheap then thats the way Ill go. I personally like buiding things my self. Right now Im working on a power supply should be cool geting the parts slowly but there is no rush and no rush for a dummy load either just want to get one in the future or build one. 73s
 
What size power supply are you building? I assume you are building the transformer/rectifier/regulartor type and not some switching power supply?
Post a few details i would'nt mind hearing about it-- I have this thing thats been sitting in my radio room for years-- its an old battery charger off a big "tanker" ship-- it charges up multiple banks of batteries and has an equizer and float switch-- made for charging up big banks of batteries for -- its got a huge ttransformer in it I been eyeing up-- i blew otu a rectifier in it and at least one transformer and they are all burried in this heat sink that you have to take apart in 4 pieces to get at-- anyways it did put out 0 to 20 volts and 30 amps constant-- all adjustable-- it was nice but I'm thinking of taking the transformer out
Let me know what your planning on building yours?
 
Nothing to fancy here realy. I am using a 6 amp battery charger for the supply. I know its sound crazy about now. lol Anyway Its kinda an experiment for me. I am going to make it unregulated and conect it to a solar panel charge controller which will be conected to a battery. The transformer itself is center taped so I need constant DC to the controller. I figure in order to do this I will need two bridge rectifiers. They will both share the center tap as one of the ac inputs I am also going to put a couple of capacitors acrost the output to help stable the DC if the bridges dont give complete DC. The tranformer was wired with two diodes to start and the center tap was the negative. This will only offer pulse DC and would probly mess the controller up. tHe controller will regulate the voltage to charge the battery so regulating will not be an isue. Dont know how well it will work but its something I am willing to try and mess with. I got to say that battery charger you have sound like it would make a good power supply! The transformer would be great for a power supply if its not shot and the variable voltage is alway a plus.
 
Thats a REALLY cool project you have there-- keep me post how its coming along
The transformer in my supply is still good-- I was actually using this thing attached to a battery as a power supply until i fried a rectifier and possibly a transistor or 2-- its a monster wall mount unit
It has a real nice transformer and nice big filter caps
let me know how things work out with your project-- keep the thread updated
Take care and good luck
 
Well so far I got one bridge rectifier. Radio shack only had one so I have to wait till they get another. :roll: Also mounted a couple of caps in the back wired in paralell.
 

dxChat
Help Users
  • No one is chatting at the moment.


      Top Bottom
      Back