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Hey Dummy; that's a Load . . .

Robb

Honorary Member Silent Key
Dec 18, 2008
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Silicon Valley CA, Storm Lake IA
Since I got an amp that is capable of legal limit power and was told that to use it correctly, I should get and use a dummy load.

I am in the shopping phase for one.
Need a bunch of input to either build one or to buy one.

The MFJ-264 is a dry dummy load that can handle 1500w for 10 seconds. But is this really enough? Can one buy this dummy and mount it in a gallon can filled with mineral oil and expect it to increase the loading time by another 10 seconds? Are there better dummy loads out there?

What do you use?

MFJ-264_ml.jpg
 
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Is 10 seconds enough? Not unless you have a -lot- of patience. Can you mount it in a can of oil and make it work longer? I have no idea but tend to doubt it. Find a 'cantenna' and fill it with mineral oil, that's about as cheap as you can get, at least for a 'legal limit' dummy load. Bigger dummy loads are just not cheap.
- 'Doc

Or make one of those salt-water dummy loads.
 
Hi robb i use a salt water dummy load works good about 5 bucks and a littel time and you are good to go. Check utube and you will find it.
 
While that is an interesting and intriguing idea; however it is a bit fragile. Not sure that it would be consistent or safe at that power level.

Thought it would stand to reason that if you take a dummy load/resistor - already rated @1.5kw - and put it in oil to dissipate the heat, that it would extend its capacity to a longer duty cycle.

If a MFJ-264 is not practical to use for 1.5kw; then what is?
 
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The hammy that told you to tune up with dummy load just didn't want to hear your tune-ups over the air. Everyone else does. You should have a legal limit antenna tuner.
 
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I have been using the same "Cantenna" style legal limit dummy load for 25 years. Just fill it with mineral oil from Walmart and your good to go. Or you can buy the oil from MFJ. I have the old Heathkit Cantenna which of course are no longer made.

MFJ Enterprises Inc.
 
Robb, if you are going to order from MFJ why get the MFJ-264 for $75 when you can get the MFJ-250 for $70. Pick up some mineral oil and away you go.

MFJ Enterprises Inc.

I have the MFJ-264 and there is NO WAY I would run a kilowatt into it for more than a second or three. When those resistors overheat they change value. Go with something at least like what I have linked too above for legal limit.

:oops: I see Ratsow8 already referenced that load above.
 
For the same price of the MFJ-264, the Ameritron ADL-1500 will take 1.5 KW for 5 minutes. It's the equivalent of the old Cantenna.

Mike
 
They are the same load Robb. Some people would rather buy it with the Ameritron name on it than MFJ I guess. Everyone knows MFJ makes junk while Ameritron makes good quality amps etc. :whistle:
 
Even if I get the Ameritron, I will still open it up and inspect the innards.

So, HRO should have one in stock. Which is 4 miles from my QTH. Prolly do that Monday or this week. Thanks, all y'all . . .
 
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I second the Palstar DL2k or DL5k. The meter reads dead on with my lp100a and I have yet to get this sucker warm. Even with 3300 watts being fed into it!!
 

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