Dummy Loads for RF

[@russellsurrey2465]

Excellent explanation…compact, clear and concise.

[@VilleWitt]

Excellent indeed. Your comment though, isn't concise as it contains pleonasm; compact & concise. Sorry, but I couldn't help myself, I'll find the exit! 😉

[@rowdyron4111]

Terrific presentation. Dummy loads don't get enough love. Please explain baluns/ununs : )

[@jamess1787]

Unun uses coax (or pretty much any unbalanced feed line) to an unbalanced (not 50ohm) antenna. ❤️

[@jamess1787]

Now, if you had a balanced line, and balanced antenna: you wouldn't need any type of signal transformer (or matching unit). Your BalBal wouldn't be needed (that's why it doesn't exist!)

[@j.p.thearmoredchef]

Happy Easter Lord Callum!

[@DXCommanderHQ]

Happy Easter!

[@DominicMazoch]

Some manual impedance matchers, like the MFJ 969, have not just a Dummy Load on them, but an antenna switch, plus ladder and long wire ports. Those things are worth the price of admission!

[@ve3pcp]

Back in the 70s, you could get a small dummy load for CB radios. It was a PL259 connector with a 47 ohm, 2.4 watt carbon resistor in it. I worked at a Radio Shack store at the time and they were very inexpensive as I recall. I still have one.

[@g0fvt]

Very useful things to have, available down to sub 1w continuous power handling. When buying them it is worth considering what frequencies you intend to use as well as the power levels. Good quality loads can maintain low SWR into the GHz region but most of us don't need that.

[@DXCommanderHQ]

Great tip!

[@DK5ONV]

Happy Easter, Lord Callum 💯🤘🙋‍♂

[@DXCommanderHQ]

Happy Easter!

[@johnratcliffe6438]

Nice video Cal.

[@DXCommanderHQ]

Thanks!

[@Apollo.308]

I regret not grabbing a used dummy load at my local hamfest cause they seem to be expensive for what they are. I couldn’t think of many scenarios where I would use one more than once a year or so for testing cables

[@piquat1]

Yes, they will emit some signal, also will RX a bit. Such that if you're doing a fox hunt (or looking for an agitator, lol) and you're really close so your RXr is pinned, pop a dummy load on there. Instant attenuation.

[@southyorkshireghosthunters]

I use a dummyload as a antenna for my gateway which just transmits around my property

[@CanispaterChristmas]

BRILLIANT!!! 👍💥

[@SeamasterSig]

Those Diamond dummy loads definitely leak. The (tr)uSDX has a menu setting for calibrating the transmitter to bring it in line with the displayed frequency if necessary. The recommended method is to attach a dummy load directly to the radio and press PTT in CW mode while observing the spectrum on a second radio tuned to the same frequency. I did this using a little Diamond DL 30A dummy load shown in the video and sure enough, the beam outside the barn I was set up in picked up the signal transmitted at 5 watts on 40 meters and the spectrum on the receiving radio showed that the little QRP rig was quite a bit off the target frequency. It didn't take long to dial it in thanks to a leaky Diamond!

[@billybiker1383]

Awesome Lord Callum

[@andy2E0JIU]

Hey cal,I wish you'd go through the intermediate book after as it's so easy to take it in the way you explain it all

[@DXCommanderHQ]

I will go through the book after Foundation.. I am quite enjoying this series.

[@andy2E0JIU]

@DXCommanderHQ ah brilliant!!!!! Look forward to it cal but nice to be refreshing your current info :) you get things across so blooming well

[@patrickbuick5459]

You talk about power supply, but also battery testing. Check out the West Mountain Radio CBA (computerized battery analyzer) tool. I use one for battery and power supply testing, but needone or more amplifiers now to test bigger ones. The audio ones are likely to do the same - act as a perfect load while testing cables, loss, matching, and output purity at certain power outputs. (You know, THD, the same as measured in RF transmitters.)

[@peterking299]

The old Tungsten filament light bulb worked fine when I used to test the TX that had valves in the O/P. But you can not buy them anymore,

[@DXCommanderHQ]

How cool!

[@keithlockstone6721]

Another way to use it is with a RF power meter. If you want to check cable loss - do 2 measurements, one with the meter next to the radio, the other with the meter next to the load. Compare the 2 measurements to see how many watts are lost in the cable. Very useful for checking cables at VHF/UHF - but you may need a meter and a load with N-type connectors though! Keith M0KIL.

[@keithlockstone6721]

Also, if you're working by yourself and the far end of the coax is far off, put your mobile phone on video record and monitor the remote end. Thus when you key the rig, you've got a record of the power meter's response.

[@OPEvers]

Are you going to move on to the intermediate book after the foundation course.. M6OPE

[@DXCommanderHQ]

Actually.. I was thinking of, yes!

[@ve3pcp]

I also have a Heathkit dummy load with a built in wattmeter that my late father built. It's a big carbon resistor inside a well ventilated metal case. Rated at 1000 watts CW.

[@DXCommanderHQ]

Lovely!

[@ZeroHarry]

A common use case for a dummy load is when testing and aligning the transmitter section of your radio.

[@DXCommanderHQ]

Good point!

[@77appyi]

you can get a dummy load for a MIG welder

[@stevencoleman7477]

what do you call a contest group " A Load of Dummys " 😂

[@DXCommanderHQ]

OK

[@vicmiller7191]

well presented Calum. Thanks ... Vic de KE8JWE

[@DXCommanderHQ]

Thanks!

[@ItsEverythingElse]

Sure you can get smaller ones.

[@paulsharp5473]

To buy one now for 1kW you need to re-mortgage.

[@DominicMazoch]

Dummy load: 1. A MP in the UK, House or Senate member in USA. 2. An antenna Willie E Coyote buys from the Acme Corporation.

[@DXCommanderHQ]

HAHA

[@James_Bowie]

Höcherl "her-sherl"

[@Rubedo777]

Hi there Antenna Alchemist… 🔮 ⚗️ Sometime whenever, would you consider doing a demo / explanation of the use of an antenna analyser… the one you have, the pro expert and the one Mike uses the MFJ. NOT how they work, the techno science, but the applications, are they good to have for someone who plays antennas rather than the folks who like aspects of radio builds / setups I mean. I’m very much of the opinion of Roly… ‘put it up see if it works…’ my problem is, my little brain keeps asking, why does it work, ok, well how does it work 🤔 Inquiring inquisitive mind… but not clever, at all 😵‍💫 This is not of your foundation license explanations which are excellent BTW… but something off piste, something to consider sometime… so for those who are clever…don’t take the piste out of us 5w brain guys and girls 😂 or me being a dummy load. 😳 🤪 Best wishes to everyone.73. 💙

[@DXCommanderHQ]

Hmmm. Good topic. I like. Noted.