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Dear all,
I’ve got this through whatsapp from a ham colleague and I think it might be of interest for the SOTA community.

QRP CW 3 bands: 20, 30, 40m



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Our friend Alain F8FEO has ordered one two weeks ago…
wait and see his next activity!

I have one.

Have you tried it out yet?
At the shack, in the field, on SOTA?
How do you like it?


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It works fine. All these simple radios are pretty similar.

The bottons, swiches, pots and display remember my old youkits.


Smallest World qrp tx for Sota in CW : 179 grammes ! 3 bands and 5 w

I will try more results in Sota (lightest )


5 bands, 5 watts, 160 grams


F8FEO any try yet with new rig…


I have posted a short review of this little radio on my YouTube Channel



143 grams

As I understand it, the mountain topper rigs don’t have volume or RF gain control. For those hams that have one, how much of an operating issue is that to you?

For small 3-band rigs, it’s down to the MTR3b and the SW-3B radios for me. Just need to pick one. . .

Hi Jim,

concerning volume control for MTR-3b, I have an inline volume control:

Anyway I rearely use that. The volume is just fine with my earphones.
An important point with MTR is to use proper earphones with low impedance.
On the first activation wiht the MTR I grabbed some cheap earphones and the volume was way too low, making it very difficult to hear lower stations. Since them I use good ones and the volume is pleasant.

Some people use external little speakers (built-in batt powered) with success, but I prefer using little earphones.

73 de Ignacio


I have few times operated my MTR and felt my eardrums almost breaking each time a chaser with a really strong signal called me and yes, that was quite of an issue for me and had to continue the activation with my earbuds partly off in order to protect my eardrums.


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The SW-3B looks like a great rig and yes I know you can never have enough radios but I have 4 other possible options already. 2 X HB-1B, KX3 and FT 817.
Ian vk5cz …

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I shopped around for earbuds with a volume control in the lead. Not many do, but when I found one, I bought two of them. I think they are essential to avoid the ear splitting effect of a strong signal. I may look into a small audio agc system to put in line with the earphones.
73 Andrew VK1DA/VK2UH

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I have the older MTR3B without the LCD display. Love it - it’s a great little rig. The lack of volume control hasn’t been an issue for me, but it can get rather loud when a really strong station is on freq.

I considered the SW-3B to replace my old MTR but there were a few deal-breakers for me: the 8 second delay after changing the keying speed, and lack of a keyer memory (other than a standard CQ message that you can’t change). If the 8 second delay were fixed, I’d probably get one (keyer memory not that important to me).

I really like the wider range of voltage the SW-3B can take!

Let us know what you end up with! Now I have to watch Richard’s review video =)


I have 2 MTR-2Bs, an LNR MTR-3B (non LCD) and an MTR-5B.

Some have said that the sidetone is too loud, I’ve never had an issue with the side tone on any of my MTRs. The newer LNR MTRs have a little PCB mounted pot to adjust the side tone, so I guess that little issue is solved.

Regarding audio levels, it’s extremely rarely that I find a signal too loud, I’m usually scratching around in the dirt! I did find that my LNR MTR had not been aligned properly so wasn’t as sensitive as it could be, it was also slightly off frequency. I couldn’t live with the issues do I stripped the rig and gave it a full re-alignment and calibration - wow- what a big difference!

I do find audio is rather low, if it’s windy, sometimes I have trouble hearing the RX. Koss ‘The Plug’ ear buds were suggested on a forum and I ordered some in. The Koss ear buds live with my MTRs, they improved matters no end for me. Not only are the ear buds very sensitive but they also have expanding foam which seals out external (wind) noise.

An inline volume control won’t hurt at all, but sure, from my experience, lack of volume control is no detriment whatsoever. The audio level is limited in the MTR, so in theory all stations from a certain strength upwards should sound the same.

73, Colin

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A quick follow-up video answering a few technical questions.


Excellent video Richard! Thanks for addressing the keyer speed change delay. That was based on AE5X’s review of the rig as I’ve never laid hands on one of these.

The wide input voltage range is great, as is the price! :+1::+1:

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