While waiting patiently (!) for the QMX to arrive, I am trying to fit out a go box. I've found several tuners in kit form. While my arthritic fingers can still solder, they are not up to winding toroids.
Recommendations for ?tuners that are not blinding expensive will be appreciated!
Thanks.
Gene
AC4ZY?

Gene, I ordered an Emtech ZM2 kit yesterday. It's not terribly expensive, and can be ordered pre-assembled for about $33 more. You might want to look into what others think about this model, to see if it would be right for you. Lots of people like the compact Elecraft auto-tuner, but I believe it is about 4 times the cost.

On 23 Aug 2023 at 12:36, Rick NF6G wrote:

I ordered an Emtech ZM2 kit
yesterday. It's not terribly
expensive, and can be ordered
pre-assembled for about $33 more. You
might want to look into what others
think about this model,

I have one that I have in my in-car POTA
setup with a QDX ... did my first activation
on Tuesday and found the ZM-2 VERY easty
to tune up ... it has a TUNE position that will
protect the QDX with no more than 2:1 swr...

One ketch ... at first, I forgot to switch from
Tune to Operate !! but still made a few QSOs
(guess I was QRPp then!) ... so I HIGHLY
recommend the ZM-2 for QDX ...

w2jc

Be aware that those type of switched-element tuners subject the transmitter to massive mismatches during switching and finding a tuning solution.? I use one but I use a QRP-O-Meter absorptive bridge between my radio and tuner;? its loss protects the TX during tuning and is then switched out.? A 6dB pad would work, too.
73, Don N2VGU?

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?? These are good, I have one I built and you can have one built by Emtech

??

????????????????????????????????????????????????? Tom, W6TOM

With my QDX I always tune my transmatch with a NanoVNA before plugging in the QDX. Doing so I am sure the QDX will be plugged in a transmatch plus antenna with less than 1.5 SWR.?
73 - Pierre - FK8IH

Recommendation is not to switch inductors while transmitting. Really pretty easy to peak up noise or signal on Rx, then just use Cin & Cout to fine tune. Rarely do you need to change inductor, but if you do, turn off Tx during switching.?
--
73, Dan? NM3A

I cannot recommend the ATU-100 Chinese look alike after having built one. If left in the automatic mode, it goes through a re-tuning cycle EVERY time you go into transmit mode even if you do not change the transmit frequency. As has been mentioned, there is no restriction on how bad the SWR can get during the tuning or retuning cycle. In the manual mode, you can step through the inductance values or the capacitance values. BUT if you change from one to the other, the setting of what you changed from will reset to zero. This has been my experience, but your results may vary,
Stephen, KO4CVU

I bought one of the ATU10 tuners. I was a little underwhelmed at first, but later firmware releases made it an excellent portable tuner. Darn close to the Elecraft tuner, IMHO.

Picture of a 4sqrp tuner...
--
73
Karl
KI4ZUQ

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Looks good Karl, does it work good for you? ?I have one sitting in a box in Florida waiting for my return to assemble it.

Although in the UK, Kanga Products make the excellent pocket transmatch as a kit but also as a complete built and tested unit. Not sure if postage to the US is viable, but worth asking.......



And my review in the RSGB Radcom magazine:

The US equivalent to the Kanga pocket trans match is EMTECH's ZM-2. 4SQRP has a similar tuner to QRP Guys and Pacific Antenna has some too.?
--
73, Dan? NM3A

Anyone tried this 4sqrp tuner above 10w spec.

On Thu, Aug 24, 2023 at 02:39 AM, Daniel Walter wrote:

Recommendation is not to switch inductors while transmitting. Really pretty easy to peak up noise or signal on Rx, then just use Cin & Cout to fine tune. Rarely do you need to change inductor, but if you do, turn off Tx during switching.?

Good advice.

Unless you know how the switch works then this advice should precedence.

But just one small note, it can depend upon the switch type.

Switches can be break and then make (potentially leaving an open circuit before the switch has made)
or can be the opposite (make before break)

Break before make or make before break.

It can make a difference to expected operation and is often overlooked when purchasing
a simple switch in other circuits too.

Now then, don't get me started about variable caps.

Linear wavelength types and linear capacitance types, mostly forgotten knowledge these days ;-)

--
- 73 de Andy -

On Wed, Aug 30, 2023 at 10:35 PM, Da Amazin' man G0FTD wrote:

Now then, don't get me started about variable caps.

Linear wavelength types and linear capacitance types, mostly forgotten knowledge these days ;-)

1.33pf per meter of wavelength and then make the inductance to suit for optimum Q.
?
--
- 73 de Andy -

Gene,

I've built and used many QRP kit ATUs. The 4SQRP antenna kit is good but it involves winding a switched inductor in combination with a 12-position switch and a large toroid.? Another good one is the BLT-Plus z-match sold by Pacific Antenna. This one uses a small toroid for the tuning indicator and a larger one for the matching inductor. A bit of peripheral parts wiring also. The tuning indicator is useful in that it provides a load of less than 2:1 SWR while adjusting for a match.
A 4-port coupler could be used for the same purpose.? My first z-match was the ZM2 and I honestly didn't care for it much.

Note that you could build the LED tuning indicator as a switchable stand-alone to be used ahead of a tuner.? QRPGuys Have/Had a kit that would do the job.

I'm not fond of buying much of any device from eBay but there are some that will do a good job. Most seem to be a T configuration, two capacitors and a switched inductor. Finding which are the good ones might be the challenge.

I recently re-packaged one of my favorite Z-Match tuner designs to fit with rigs like the QMX. Inof is shareable...8^)
--

Chuck, W5USJ
EM22cv, Rains Co., Texas