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? Yoon,
Thank you for your reply. ?I had some time to waste yesterday (my XYL was driving) and I found the key on sale at eBay and Amazon, between $22 and $28 USD depending on the little accessories.?
?I went to the reviews and there was only one review from a very dissatisfied owner. I added another review more positive.?
?It’s a neat little key for backpacking or just learning, well built for the cost, only has two adjustments so it’s easy to set up. Magnetic base so it will stick to many rigs. I own many keys from a low cost White Rook MK-44 plastic thingy (that I love and grab for testing something new…. No adjustments at all) up to expensive Begali ones but this little key works and if lost or something breaks one is not out much. ?I would recommend one for anybody’s go bag.
Dave K8WPE
PS ?Now I understand…… He who dies with the most toys has probably forgotten much what he has and why……. So true!
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On Feb 22, 2025, at 12:15?PM, Yoon KM6KJI via groups.io <yoonh.choi@...> wrote:
? On Sat, Feb 22, 2025 at 03:26 AM, David Wilcox K8WPE wrote:
Where did you get that neat key in this photo?
You can search QU-7025 to find it. It's cheap and not any fancy, but works. I added the guardrail to prevent the levers from being derailed accidentally.
?
73,
Yoon KM6KJI
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Hi Yoon,
?
I really like your design!
It always makes me feel nervous to see a long antenna attached directly to the rig (imagining the stress on the circuit board).
The boot and hat arrangement could be made very strong and easy/cheap to repair/replace if it breaks.
?
73, Mike KK7ER
?
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On Fri, Feb 21, 2025 at 08:01 AM, Steve Sutterer AK0M wrote:
Has anyone considered or even actually built an integrated handheld QMX rig? I am thinking something like the KH1. I can envision a 3D printed case that includes the QMX, small battery pack, and a manual Z-match or even automatic tuner that could be used with a whip or random wire antenna. Could include integrated touch paddles or paddles jack…
Back to the original topic, I was also imagining something similar, docking like the attached sketch - though it is not a 3d printed case but an aluminum enclosure. It is still only imagination, as I can't find an enclosure that has the same width and depth as the QMX enclosure. Sadly I don't have a 3d printer nor any skill to create something out of it.
?
?
73,
Yoon KM6KJI
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This is the golden age of electronic experimentation.
I wholeheartedly agree.? I've designed three PCBs for antennas (two baluns and a T-match tuner) in kicad in the last few months.? Building and troubleshooting my QMX has brought me closer to buying my own oscilloscope, and I'm considering doing a run of kits using the affordable PCB assembly services now available to us all.? It is definitely a good time to be in the hobby :)
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This is the golden age of electronic experimentation.
I can design a PCB in Kicad and have 5 boards built and delivered in a week or two for $5.
Parts for a complete transceiver similar to the Micro-mountaineer can be found online?
for a grand total of maybe $10, along with all the needed datasheets.
A $15 RPi-Zero would run circles around a million dollar Cray 1 for DSP algorithms.
?
Communications is no longer problematic in an era of cell phones and email, radio isn't quite so magical.
Many of the experimenters have moved on to DIY audio, electric vehicles, robotics, off-grid power.?
?
The big thing in RF power amps these days is Current Mode Class D, or CMCD.
This is considered a further development beyond Class E or Class F, and the subject of numerous MS and PHd theses.
?
Curiously enough, it's the AM phone crowd doing much of the experimentation with DIY builds in ham radio.
A CMCD type RF amp with a Class D AM modulator could be easily adapted for use with Hans' Synthesized EER scheme.
The INN650D02's mentioned by KJ7AGO in that final web link above are $1 on Aliexpress, I've got 20 getting shipped this way.
?
Around 1970, an aging ham gifted me with his junk box.
Included some Ford coils with which to build a spark gap transmitter.
(Scary to think that he was younger than I am now.)
Also a 2kv 2kW plate transformer and a couple dozen 810 triodes.
Still have the 810's down in the basement, and occasionally consider building this push-pull amp:
?
Curiously, that 810 design from 1938 has the topology of a Current Mode Class D amplifier.
There are published examples of that design dating back to about 1930.
This 1934 guide for amateurs has many different CMCD style designs.
Those guys knew what worked, and I'm sure they fiddled with drive levels and? tank circuit C,L values
till they got maximum efficiency.? ?Which would put it in CMCD mode with ZVS.
?
Jerry, KE7ER
?
?
On Sat, Feb 22, 2025 at 07:38 AM, bill K7WXW wrote:
I don’t know, Jerry, maybe not the norm, but a significant proportion of hams built their own gear back then. “Solid state design for the radio amateur” sold more than 50,000 copies, the ARRL handbook was filled with practical projects and a reasonable amount of electronic and RF theory, and there were still lots of local places to buy parts. I was a digital design engineer in those days, and did RF stuff when I got tired of zeros and ones.
?
Or maybe my nostalgia for the golden years of DIY PCBs, ECL and 40763s, leaded components, and deadbugging continue to get the better of me. :)
?
bill K7WXW
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On Sat, Feb 22, 2025 at 03:26 AM, David Wilcox K8WPE wrote:
Where did you get that neat key in this photo?
You can search QU-7025 to find it. It's cheap and not any fancy, but works. I added the guardrail to prevent the levers from being derailed accidentally.
?
73,
Yoon KM6KJI
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And here I always thought those dual gate FETs were 40673’s. ?Ahh, the good old days when parts were visible and the part numbers could be read by the unaided eye.
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On Feb 22, 2025, at 10:38, bill K7WXW via groups.io <K7WXW@...> wrote:
? I don’t know, Jerry, maybe not the norm, but a significant proportion of hams built their own gear back then. “Solid state design for the radio amateur” sold more than 50,000 copies, the ARRL handbook was filled with practical projects and a reasonable amount of electronic and RF theory, and there were still lots of local places to buy parts. I was a digital design engineer in those days, and did RF stuff when I got tired of zeros and ones.
?
Or maybe my nostalgia for the golden years of DIY PCBs, ECL and 40763s, leaded components, and deadbugging continue to get the better of me. :)
?
bill K7WXW
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I don’t know, Jerry, maybe not the norm, but a significant proportion of hams built their own gear back then. “Solid state design for the radio amateur” sold more than 50,000 copies, the ARRL handbook was filled with practical projects and a reasonable amount of electronic and RF theory, and there were still lots of local places to buy parts. I was a digital design engineer in those days, and did RF stuff when I got tired of zeros and ones.
?
Or maybe my nostalgia for the golden years of DIY PCBs, ECL and 40763s, leaded components, and deadbugging continue to get the better of me. :)
?
bill K7WXW
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N6ARA is working on a tiny-tunable-antenna (based on the "" design antenna that seems popular in...Asia) that can go directly on small QRP rigs. https://www.instagram.com/p/DD5xJzuPVHj/?img_index=1
?
This may be a winner for super fast and light field use with the QMX - frankly, any QRP radio.
?
Also note tiny paddle at bottom plugged right into key port - he’s built a poor-man’s KH1.
?
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Yoon, I have had some RF feedback using my KH1 at times in certain circumstances. ?It was usually on my deck in a stucco sided 3rd floor condo here in Florida. ?I was using my SuperAntenna MP-1 fastened to the deck railing. ?I then put a CMC out 10’ in the feedline and that solved the problem.? Dave K8WPE
PS ?Now I understand…… He who dies with the most toys has probably forgotten much what he has and why……. So true!
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On Feb 21, 2025, at 4:08?PM, Yoon KM6KJI via groups.io <yoonh.choi@...> wrote:
? On Fri, Feb 21, 2025 at 11:49 AM, Wei AG6AQ wrote:
I was inspired by your post and tried myself with MFJ1720, the major problem is RFI. Have you seen RFI problem in your handheld setting?
Wei, what was the symptom of the RFI problem? Maybe some erratic behaviors of QMX like turning off itself or the keyer suddenly not working, etc.?
?
I do remember having that kind of problems when trying handheld operation with different whip antennas and certain lengths of counterpoise wire. I think the problem can be generally minimized with the lowest SWR you can achieve, although there are many other factors affecting the antenna match with HT operation - your hand, head, body and your posture, also the dry or wet ground where you stand on, etc.
?
Then I found it very handy to use the reel wire as the counterpoise, with which you can easily find the best match in any circumstances, which will surely minimize the RFI problem. I haven't had the problem with my whip antenna and the reel counterpoise wire.
?
73,
Yoon KM6KJI
?
?
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Yoon,
Where did you get that neat key in this photo?
A friend of mine gave me one just like it yesterday at breakfast. He thought it was a prototype as it was included as a freebie when he ordered a cap/resistance measuring device from Denmark. He uses big manly keys so had no use for it. Ha! ?I am finding that it has a nice feel and will no doubt use it with some of my QRP rigs.?
Dave (Djwilcox01 at gmail)
Dave K8WPE
PS ?Now I understand…… He who dies with the most toys has probably forgotten much what he has and why……. So true!
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On Feb 21, 2025, at 2:32?PM, Yoon KM6KJI via groups.io <yoonh.choi@...> wrote:
? It seems any photos attached to a thread are gone after a couple of weeks? So instead of posting my handheld QMX photos here again, I recommend you to visit my QRZ page to see how I'm operating QMX as HT -
?
I have integrated it with the battery (3s1p 14500 li-ion cells with BMS), the internal speaker (though not much useful for noisy outdoor), and the plugin single lever cw paddle. For the whip antenna and the reel counterpoise wire combined with the QMX's built-in SWR bridge, I don't need an ATU.
?
73,
Yoon KM6KJI
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Wes Hayward was not the norm (and still isn't).
Check the station photos toward the back of that 52 yr old QST, all appliance gear.
Lots of Heathkits, though that's hardly building your own.?
You pretty much have to go back to before WWII to find a time when most hams built their own gear.
?
I'll look out for issues with the touch paddle.
Seems a common mode choke in the transmission line should cure issues with RF in the shack.
Especially at 5 Watts.
?
Jerry, KE7ER
?
On Fri, Feb 21, 2025 at 09:27 PM, Peter HB9EBE wrote:
Great stuff Jerry, and good to take a look back when building was the norm!
Just a word on the touch keyer. I built it, because touch is what I had in the old times. With the QCX I found it to be quite temperamental depending on the antenna (RF I guess), so moved on to the pressure paddle.
?
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Great stuff Jerry, and good to take a look back when building was the norm!
Just a word on the touch keyer. I built it, because touch is what I had in the old times. With the QCX I found it to be quite temperamental depending on the antenna (RF I guess), so moved on to the pressure paddle.
?
73, Peter
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Go down 7 photos here, Wes working his Micro-mountaineer is the small black and white photo to the right:
?
His QST article describing the Micro-mountaineer starts on page 11:
?
Built it shortly after that was published in 1973.
Laid out and etched my own board with ferric cloride.
A step up from them Pixie thingies on ebay today.
Lots of plans for it, but made perhaps 2 contacts.
Climbed Mt Hood, but didn't bother taking the Micro-mountaineer.
It's in a box somewhere down in the basement.
?
Also in that issue:? the WB4VVF Accu-Keyer.
Built that too, I think it's down there in the same box.
After 40 years as a digital design engineer I took another look
at the schematic, still can't figure out how all of it works.
A very elegant design, but uses some nasty tricks.
Set the standard for decades to come on how a keyer should behave.
?
Another article in that issue was the third installment of W2DU's
"Another Look at Reflections".? That I did figure out a few years ago
but it was some very tough sledding.? He had some nice insights?
into how transmission lines work, but no idea how to write.
?
?
I just bought some AT42QT1011's so I can add M0UKD's touch keyer to my QMX
?
Jerry, KE7ER
?
?
?
On Fri, Feb 21, 2025 at 07:04 PM, Curt wb8yyy wrote:
Many years ago W7ZOI is pictured with a handheld cw rig. Key is attached, maybe battery in his pocket and a wire antenna is deployed into a tree. Certainly qmx can do this with a suitable key. I may have seen something pictured here recently.?
?
Curt
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Many years ago W7ZOI is pictured with a handheld cw rig. Key is attached, maybe battery in his pocket and a wire antenna is deployed into a tree. Certainly qmx can do this with a suitable key. I may have seen something pictured here recently.?
?
Curt
?
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Hi Yoon,
?
Yes, besides erratic behaviors you described, the side tone also sounds funny.
Looks like to use reel wire to lower the SWR is the key. I could only get 1.8:1 from MFJ1720 as I remembered.?
?
I will try on 10/12m again. If it works, it will be a good supplement to KH1.
?
73
Wei AG6AQ
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On Fri, Feb 21, 2025 at 11:49 AM, Wei AG6AQ wrote:
I was inspired by your post and tried myself with MFJ1720, the major problem is RFI. Have you seen RFI problem in your handheld setting?
Wei, what was the symptom of the RFI problem? Maybe some erratic behaviors of QMX like turning off itself or the keyer suddenly not working, etc.?
?
I do remember having that kind of problems when trying handheld operation with different whip antennas and certain lengths of counterpoise wire. I think the problem can be generally minimized with the lowest SWR you can achieve, although there are many other factors affecting the antenna match with HT operation - your hand, head, body and your posture, also the dry or wet ground where you stand on, etc.
?
Then I found it very handy to use the reel wire as the counterpoise, with which you can easily find the best match in any circumstances, which will surely minimize the RFI problem. I haven't had the problem with my whip antenna and the reel counterpoise wire.
?
73,
Yoon KM6KJI
?
?
|
Hi Yoon,
?
I was inspired by your post and tried myself with MFJ1720, the major problem is RFI. Have you seen RFI problem in your handheld setting?
?
I can put battery in my pocket to reduce weight/volume and I agree ATU is not needed if you tune the antenna first.
?
73,
Wei AG6AQ
|
It seems any photos attached to a thread are gone after a couple of weeks? So instead of posting my handheld QMX photos here again, I recommend you to visit my QRZ page to see how I'm operating QMX as HT -
?
I have integrated it with the battery (3s1p 14500 li-ion cells with BMS), the internal speaker (though not much useful for noisy outdoor), and the plugin single lever cw paddle. For the whip antenna and the reel counterpoise wire combined with the QMX's built-in SWR bridge, I don't need an ATU.
?
73,
Yoon KM6KJI
|
On Fri, Feb 21, 2025 at 06:11 PM, Wei AG6AQ wrote:
Somehow, handheld HF is an under-served market segment.
?
?
Try putting a simple 50-150cm whip antenna on an HF TX and then
measure the performance / narrow bandwidths / low effiency / variable
impedance due to numerous external factors whilst actually operating.
?
Interesting and educational , but you'll soon move on ;-)
?
[Same practical issues for 27/28Mhz/50Mhz HT's, and why barely
anyone bothers with their EDC operations].
?
Just stick to throwing a wire up a tree / convenient sky hook with a
mini rig.
?
- Andy -
?
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David Wilcox K8WPE
bill K7WXW
Peter HB9EBE