Thursday 12 November 2020



Being a newly licensed amateur radio enthusiast with transceivers and long wire antennas, it soon becomes evident that ATUs are not only great for transmitting, but also for receiving. Getting the right match between antenna and receiver greatly boosts those weaker stations to the point where it makes the difference between hearing them clearly or struggling to make any sense of the signal.

When I installed an SDRPLAY RSPdx in the corner of my lounge or when I use my AR3000A, I found myself wanting to tune the G5RV to get a better match and a stronger signal, so I decided to buy a tuner. Sadly, the vast majority of manual tuners on the market are made for transceivers and are very expensive.

I posted on some SWL forums/groups for some recommendations and I got quite a few links sent to me which pointed to Auto ATUs. Obviously, Auto ATUs need to transmit in order to get a match, so they were no good. When I pointed this out to people, they got quite snotty and defensive, so I just moved on. 😕

Finally, I found a cheap solution in the GLOBAL COUPLER AT-1000 which is an older piece of equipment which can be found on eBay for around £60. The one I bought was actually from my local Radio Club - it was surplus to requirements.

The unit looks a little old fashioned, but it's perfectly functional and in great condition - the front panel in particular, is in fantastic shape. All the screws are original and apart from some of the usual marks to the case's paintwork, it's like new. 

Inside is the same - probably better, in fact, than some newer-built stuff!

Unfortunately, I couldn't find a manual for it online, so I had to refer to one for the AT-2000 which is very similar. It's pretty obvious what you've got to do anyway! You connect your antenna to the "ANT" SO-239 on the back and then connect a patch-lead from the Coupler to your radio's antenna input.

Once you're ready to listen to a frequency, tune your radio to it, then on the Coupler, you choose your band with the BAND SELECTOR, adjust the TUNING-1 dial until you get the best signal, then adjust the TUNING-2 dial to improve it further. Once you've got a better, clearer signal, you can again make a final tweak by repeating the operation for finer-tuning.

Is it as good as just pressing a button on an AUTO ATU?? No, of course not, but it does the job and gets you a better antenna match and therefore a better (usually) signal. Without it, you're simply stuck with whatever you can hear.

Is it worth it? Yes, they're a really handy tool to have in the SWL toolkit and the good thing about stuff like this is they never really lose their value.

Thanks for popping by.

73, Tom, M7MCQ.


PE4BAS, Bas said...

Very good article Tom. Most SWL listeners never heard about boosting their signal with a antennatuner. But it definitely helps and it does have a filtering effect as well. This one is nice looking but you can easily build one yourself with some parts from an old defective transistorradio. 73, Bas

Unknown said...

Hi Tom,
Hope you got the email I sent about these Mizuho Tuner/Couplers.
The "Global" brand was used by Waters and Stanton (UK) who imported them into European market. I think the AT-1000 is Mizuho KX-2 or KX-3. Mike

MadDogMcQ said...

Yes I got your email (just now sorry). Very much appreciated (including your kind comments regarding my blog). Best regards, Tom, M7MCQ