Ultra Portable Radios.

Started by gil, July 16, 2015, 03:07:29 am

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gil

Hello,

I have been thinking that what I am most interested in isn't truly QRP, but ultra-portable radios (UPRs?). The definition of QRP is a power limited to five Watts in CW or ten in SSB. You can reduce power on a rig the size of a washing machine connected to a five-element Yagi and still be QRP. My favorite radios have all been QRP, but only because of their size. What I really want is something I can carry in a backpack, or even better, in a coat pocket. I'd be happy to have a twenty-Watt CW radio that fits on the palm of my hand. The only problem would be the transmit current draw. Ultra-portable means that the battery has to qualify as well.

A UPR would need to be very small; no bigger than an Elecraft KX1, which would only qualify because the case has space for batteries. I can think of the Weber MTR as the best example, or a Rock-Mite. Any mode can qualify as long as the radio is small enough. I would not include radios that can't work without a computer. The typical power source would be eight AA cells or a small 3S lipo pack.

Surface-mount components have made the impossible possible, and we haven't seen the last of it. Designs will only appear however if there is a demand or at least some interest. Hence my reason for writing this.

Looking at Youtube videos of emergency communications setups, I mostly see "go-boxes" the size of a small fridge powered by a big battery or a generator. That is great for community support with some kind of an infrastructure in place or for a short duration, such as we've seen with Katrina or Sandy. However, when it comes to individual communications, we only find VHF/UHF handhelds. I believe that there is a place for long-range radios that fit in a bug-out bag without being felt. There is no need in our case for a power limit other than dictated by portability and air time.

Let's make a list of available UPRs, just for kicks!

I nominate the KX1 and the MTR. What else?

Greywolf69

If you want real URP you need to build your own, there are plenty of matchbox QRP rig designs on the net. Small enough to fit in an altoids tin (inc. battery) the antenna is then the bulkiest part of the setup.

Your thread reminded me of an article in a radio com magazine back in the 80's, wish I could remember which one because the article had circuit designs and )to me) it looked like a clean and uncluttered build.

Oh, I did a diploma in Rad-comms back in the 80's and still find circuits "pretty" when they are right ;)

gil

Indeed, most come as kits.. The Weber MTR though is now sold by LNR Precision, but I can't think of any other that come as a pre-built radio.. One doesn't need to be an electronics guru to build one however, and you can learn soldering in ten minutes. Being very meticulous should produce a working radio the first time power is applied. If there is smoke though, that's when the "fun" starts. I would suggest anyone to start with an easy kit, like a Rock-Mite. In any case, the quality of the manual will in great part determine chances of success. The best manuals and kits are from Elecraft, hands down. Having to build a radio shouldn't be seen as an obstacle, and learning some electronics goes a long way towards self-sufficiency.

Gil.

Greywolf69

Don't release the magic smoke!
I used to spend hours soldering  for someone else. Now it's time to do it for me :)

Wayne

Hi Gil,

I took your post of a year ago as a challenge to be met :)  The result is pocket-sized: the Elecraft KX2. It's the size of the KX1, but covers 80-10 m, with SSB/CW/data modes, and has 10 watts output. Most of the same features as the KX3 at a much lower price. Current drain is about as low as physically possible with 32-bit DSP -- 135 mA minimum with the preamp and backlight off.

You can use it table-stop or hand-held, like an HT, with a whip. Has an internal wide-range ATU, internal 2.6 Ah Li-ion battery, built-in mic and speaker. Weighs 13 oz. less battery. 1.5 x 2.8 x 5.8".

Be happy to have you try one.

Wayne
N6KR


Quote from: gil on July 16, 2015, 03:07:29 am
I have been thinking that what I am most interested in isn't truly QRP, but ultra-portable radios (UPRs?). The definition of QRP is a power limited to five Watts in CW or ten in SSB. You can reduce power on a rig the size of a washing machine connected to a five-element Yagi and still be QRP. My favorite radios have all been QRP, but only because of their size. What I really want is something I can carry in a backpack, or even better, in a coat pocket. I'd be happy to have a twenty-Watt CW radio that fits on the palm of my hand. The only problem would be the transmit current draw. Ultra-portable means that the battery has to qualify as well.

Sparks

May 18, 2016, 06:52:22 pm #5 Last Edit: May 18, 2016, 06:57:37 pm by Sparks
I was composing posts on the Elecraft KX2 while Wayne posted the foregoing:

http://radiopreppers.com/index.php/topic,1098.0.html
The Elecraft KX2 will be announced this week (May, 2016

RadioRay

UPR is the next iteration of the Trail Friendly Radio revolution. 

Wayne, good to see you here. Looking at the KX2, I think you really are filling the void for a high performance, yet field friendly HF rig.  When they become generally available, I'll likely put it right next to my well worn Wilderness Sierra - still going strong after all these years.

- Top mounted controls. ( In thousands of trail miles, I've usually operated from the ground, so a 'shelf friendly' design is no friend to wilderness ops.

- Small enough to take with you. (A watertight hardcase would still be something I'd find and buy.)

- =<10 Watts with built-in ATU.  (Few cables and connectors to go wrong.)

- General coverage receiver!

- 60 and 80 meters for NVIS duing solar minima.

I found this link: dream fuel for go-anywhere radio nuts like us.


https://drive.google.com/file/d/0B4hTm2wk0Fk8aUNqaUtrWmM3bHZlQVBIZFZmMXMzY3UxM21j/view?pref=2&pli=1


73 de RadioRay  /..._  ._

Ps. What's a "microphone" ?  I've heard of them, but can't seem to remember what they're for.   ::)
"When we cannot do the good we would, we must be ready to do the good we can."  ~ Matthew Henry

cockpitbob

Wayne, welcome aboard.  Check back in from time to time  ;D

Only a lack of spare time has stopped me from buying an FT-817 so I can do digital as well as all modes and bands.  I'm glad I waited.  The KX2 just bumped the 817 off the "soon as things slow down" list.  I think my MTR-3B and a KX2 will fill all my QRP needs and I can dump my other 3 QRP rigs.  ;D

gil

May 19, 2016, 03:44:16 am #8 Last Edit: May 19, 2016, 03:55:48 am by gil
Wow! Thank you Wayne! You probably just sold one.. When can we know more and see photos? Hell, I'd love to beta test one, but don't expect to get it back ;-) just a check, LOL. I built a K2 and K1, even bought a KX3, so, pretty please, being the inspiration and all..

Gil

gil

There it is, Steve WG0AT got one...

https://youtu.be/2CyCoqBhlCQ

I'd say the KX2 qualifies as a UPR, barely, because of size. It certainly exceeds my hopes as far as features. If it is as good as the KX3 then Elecraft has another winner. While not ultra small, the size difference with the KX3 seems significant. Glad it retained the same excellent display.

I sold my KX3 because I needed money but also because I was only using a fraction of its capabilities. The same would probably be true of the KX2 but in time I would get nearer its full potential. The K1 to me was a near-perfect radio with the four band module. A K1 with SSB and 80m would have been ideal. Technology advances rapidly though and the KX2 is the result.

QuoteBe happy to have you try one.


Wayne, I just emailed you my address! I'd do a review in French too, and what a great excuse to take the train to the Alps and try SOTA...

Gil

RadioRay

May 21, 2016, 11:24:17 am #10 Last Edit: May 22, 2016, 10:30:44 am by RadioRay
! QRP Comrades !
Join The UPR
Revolution !




From each according to their power budget
, TO each according to their gain/noise figure.


Radio for the proletarriat.... pro-li-tariyat.... uh. ..... for the little guy!

"When we cannot do the good we would, we must be ready to do the good we can."  ~ Matthew Henry

gil

Ray, the photo isn't showing...

Gil

RadioRay

May 22, 2016, 10:33:50 am #12 Last Edit: May 22, 2016, 10:42:19 am by RadioRay
I've inserted a few QRP REVOLUTION! attachments.  Click to enlarge.  Evidently, qrz.com blocked linking to my pictures there. I can understand that - it's their site.

>Ray
"When we cannot do the good we would, we must be ready to do the good we can."  ~ Matthew Henry

gil

May 22, 2016, 02:40:20 pm #13 Last Edit: May 22, 2016, 02:41:55 pm by gil
Excellent Ray, albeit slightly scary ;-)
Mind if I share those images?

Gil

gil

Beyond QRP, where size only matters, Ultra Portable Radios!