MFJ Enterprises Original MFJ-260C Dummy Load, 300 Watt, 0-650 MHz, Dry

What can I say, its a big resistor in a box! You would think that they could have the greenest newbs assembling these but maybe I give newbs too much credit. I opened the box and found one of the case screws started at about 30 degrees from straight on and only screwed about half way so the screw was sticking out a good 1/4. I removed the screw and installed it straight and fully without any issues but it seems ridiculous that something this simple was brushed over at the factory.

This is supposed to be a 50 ohm dummy load. It is an open circuit, very bad for the finals on a transmitter. The design uses the aluminum case as the ground connection for one end of the resistor. The case must be oxidized of coated. Do not buy this product. You can get the same functionality by not attaching anything to the output of your transmitter.

This dummy load performs well and I use it whenever I am on the air with a Collins 32S-3 running 150 watts CW or a Yaesu FT-101B. I switch it in with an MFJ-1700B multi-port transmitter/antenna switch and its been functioning perfectly for almost a year. I installed it, put it under the operating desk and never had to look at it again - and thats the way it should be. NOTE: This dummy load is labeled as 300 watts and the derating curve gives it 60 seconds at 300 watts on a continuous duty cycle. When I use it for tuning it heats pretty well in under a minute with only a few continuous seconds at any time (I would estimate a 30% duty cycle). Sometimes this is a short time to tune-up old technology tube equipment like the Collins. This dummy load can do a max of three minutes at 25 watts continuous so the rating probably should be closer to 100 watts where the derating curve shows about 90 seconds of a continuous duty cycle. Whatever. Its a great accessory and I wish more people would use it to tune up before going on the air.

it works okay.

Super

This came as a gift to my husband. He really likes it.

works great

Easy to use right out of the box. Used it along with my antenna analyzer to verify that my coax was working.

This dummy load was DOA (dead on arrival). I tested with an ohmmeter and then with a Nano VNA, it was open circuit. I took the case off and inspected it, and did some probing with the ohm meter, the actual big fat resistor was 51.5 ohms, which was within the specification, that was not the issue. The problem is that one end of the resistor clamp relies on a push fit contact with the aluminum case for the return earth path. Aluminum oxidizes to produce aluminum oxide (AL2 O3) with is an isolator, so there is an insulator between the 50 resistor and the case. Ive read other reviews where people have fixed it, well aluminum can oxidize in as little as 1 month so I would not trust that fix. Im not going to risk my $1000 transceiver on this piece of junk. This is a very poor design, has a fatal error and can only be fixed by installing a dedicated copper earth return wire back to the connector. So I guess its true what I read online MFJ = Mighty Fine Junk

Item as described and worked well dissipating 100 watts up to the ten meter band. Measured the resistance 49.0 ohms (corrected for lead resistance).