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MTR-5B ufb rig

Dear SOTA-Activators
Today I was using the MTR-5B for the first time. It is a five bands Mountain topper (40/30/20/17/15 meter, cw only. The kit was made by Steve, KD1JV. The rig has a LCD display and 4w output. The small size fits into a 4” x 3” x ¾” box. Soon it will also be available at LNR Precision Inc. The KX3 is my best QRP-Rig! But the MTR-5B is much lighter and cheaper. I recommend this QRP-Kit to every CW-Freak for long trips! Thank you to Steve, KD1JV for this excellent QRP-Rig! We will more speak abt this rig at the Ham Radio 2016 in FH.
73 de HB9BIN, Jürg


Fantastic Jurg - I know that Colin M1BUU has just built this radio and I think is about to take it on to the hill. I worked you today and you were a very respectable 579 on 40m.

I’ll be at Ham Radio in 2016 and hope we can meet again and I will find out more about the MTR-5B.

73 de Phil

Thanks Jürg for the feedback.
I knew Colin had one because he recently posted a picture of it here, but I didn’t know he put it together himself.

I wonder how difficult assemblying this kit is.
Colin, should you read this post, would you, please, explain how difficult you found putting this kit together?
Are there any SMD components?
Are any adjustments necessary as to need lab equipment such as oscilloscope, signal generators or something like that?
I feel like including it in my letter to Santa and I’d love to be able to buid on my own if that’s possible.
Thanks in advance and best 73 de Guru.

KD1JV’s radios are good units for the lightweight SOTA enthusiast. I built the Tri bander which I use for my overnight full pack treks where weight is a important consideration.

The radios are very economical on batteries.

A set of rechargeable 2600mA AA’s comfortably will do three activations.

73’s, Nick

Hi Guru; SMD? Plenty of them!!

You can see Colin building it:

By the way a wonderful SOTA rig! I love mine. But I’d like a rotary knob on it…
73 de Ignacio

I’m getting old, Ignacio.
I had seen this video some time ago but I had completely forgotten.
I don’t think I’d dare soldering all those tiny SMDs…
Thank you for reminding me.
73 de Guru

Do you know if it is the same design as the original MTR except 5 band and LCD display or is it a complete re-design?

73 Andrew G4AFI


I’ve built two of these kits, but so far I haven’t had much operating experience with them. The build process was much like previous versions of MTR rigs although there were more SMD components this time around.

There were a few serious firmware issues to sort out and also the original reference oscillator was misbehaving.

The build instructions can be read here - note that no case was provided with the kit but LNR Precision are now offering one, and presumably it will be used for the commercial fully built unit that they’ll offer in the future.


73, Colin M1BUU

Very similar to previous versions. RX current is now down to around 25mA due to a switch mode regulator.

An optional rotary encoder can be added if desired for ease of frequency adjustment.

73, Colin M1BUU

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sigh if only i could use CW that setup looks so much lighter to carry than my TS-480.

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lighter than my ts-480 is around 4 kg. Trying to justify the purchase of a ft817 just to save me carrying more weight.

That’s an impressive weight Colin.
My ATS4, which is really the predecessor to the 5B is 180g, so this baby would save me 20g in my pack :slight_smile:

Nice rig, but I couldn’t justify buying one and stopping someone, without a KD1JV rig, the opportunity of joining the exclusive club!
I’d still love one for my collection so if anyone has a spare kit for the 5b or the triband MTR I’m all ears :blush:

I still reckon, that if you can manage with with only 2 bands, then the original MTR at 75g is unbeatable.

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Of course I was just being silly, you can’t run the rig without it’s ancillaries, so I reckon you’ve got to add at least another 500g to rig weight to cover earphones, key, antenna, antenna support.

So you’re still looking at 1kg or just under for the whole setup.

73, Colin M1BUU

That’s very good!

My KX-1 weighs 270 g, ie, almost 50% more…
And sometimes a gr in excess is tooooo much!

Also, it will be nice to have 5 bands!

73 de Pedro, CT1DBS

160g - hmm, that’s impressive. A full 13g less than the FT-817 microphone!
That’s the price of having SSB capability. :wink:

You will probably make up the difference in weight quite quickly as “things” start to creep into your backpack. The only way to prevent this is not to carry out any activations. :wink:

The entire ATS/MTR series are just variations on a theme.
They’re pretty much the same Tx/Rx architecture throughout, differing mainly in processor, DDS, display and band switching/plugin options. Obviously, as they evolve, components change to replace obsolete parts and make use of newer devices.
The ATS4 was the first step away from the Altoids tin format to allow space for the display and pentaband switching, but Steve went back to the Altoids format in the original MTR.
Later the tribander and pentaband MTR again necessitated the slightly larger footprint which could not be accommodated in the Altoids tin.
Sounds like Steve is going to go back to basics with maybe some single banders. Perhaps these will be in an even smaller case :smiley:

All the ATS schematics are available on the AT Sprint group pages.

Great post Pete!

I really don’t need any more radios (as someone pointed out on Twitter yesterday!), but I’d love an Altoids sized self contained single band rig, complete with internal battery, that would be cool!

BTW, for a lighter MTR-5B, the PCB would fit in a Tobacco tin. I bought a suitable tobacco tin whilst in Colchester from the 99p store, but I decided to make my own case from a piece of 1.2mm aluminium sourced from EBay. Picture shows Tobacco tin that would fit and previous MTRs for size comparison. Altoids MTR weighs 80g, whilst blue 2nd run MTR weighs 170g due to part steel case. I believe that Jürg’s rig is in a plastic case, I wonder if Jürg might enlighten us with the weight?

I’m missing a Tri Band MTR :cry: LOL

73, Colin M1BUU


Bring one out with a mike and I would be interested! :grinning:

Hi Colin
Yes, I have a plastic case! You won. You have beaten me by three gr (hi hi hi). The weight of my kit is 163 gr. (see the picture).

In this topic, we only discuss the weight of the MTR-5B. We must point out the huge progress Steve made between the Mountain Topper offered by LNR Precision Inc. and the MTR-5B Kit with its new display (see the picture)!
73 de HB9BIN, Jürg