LPF Do I understand it correctly that on 3.5 Mhz I am 20 db down ?

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SWR Sweep with dummy load. That looks ok to me.

image Sweep

RF Filter Sweep

I managed to get that PuTTY to start.

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Audio

We had 10 folks attend the Michigan QRP Club Zoom meeting last week where the topic was keys.

Pete WK8S

Ed AB8DF

Ernie W3ETE

Stuart M0SGV

Dave N8SBE

Muhsin TA1MHS

Rick K8MBA

Jeremy KD8ZZJ

TBD TA1HMG

Casey KC9IH

Keys

Pete showed pictures of his keys. Not good with straight keys any more. Muhsin showed his first key and the history behind it. Dave’s first QRP was a bulldog built with paper clips. He also has Bencher paddles, Kent paddles, and Bengalis. Ed showed his straight keys and paddles which included J38, Bencher straight key, NORCAL paddle kit and Kent paddles. He uses a Bengali Simplex as his daily paddle. Stuart showed a bunch of keys. He has way too many. Rick is a single lever guy. He talked about his single lever paddles. There sure are many different kinds of keys and keying style. Lots of interesting stories. Favorite QRP rig will be the topic for next week 25 July. Stuart sent in a poem about Morse code:

If you can keep your head when all the buntings
Are losing theirs and blaming it on you;
If you can read through abnospheric crashes .
With signals fading down to near "R-2";?

If you can send and not get tired sending
And when you stumble, make a neat erase;
If you can read without the old complaining:
"His bloody Morse is just a damn disgrace";?

If you don't fill the unforgiving minute
With sixty seconds worth of IMI's
And if you always use correct procedure,
But still don't talk too much, nor look too wise;?

If you can live with buntings, jeeps and stokers
And tolerate both Pusser's rum and stew;
And copy when reliefs are in their hammocks
And never miss a group with every spew;?

If officers and Chiefs and drunken Yeomen
Can heckle you and still your nerves won't fray;
Then you're a damn good sparker, son - you've made it!
You're earning every penny of your pay. . . .?

At the end of the meeting we did a quick survey with those in attendance.

Who uses what kind? Survey below:

Straight -?

Paddles Iambic - 4

Paddles single lever - 1

Side Swiper -?

Cootie -?

Single lever -?

Other - 1

Please join us Thursday (and every Thursday) at 4PM Eastern for the Michigan QRP Club weekly QRP Chat where the main topics will be QRP and other ham interests. It's fun, it's easy, and it's free. You only need a computer, a smart phone, or a tablet that can connect to the Internet. OR if you can't be close to any of those you can join by audio with any standard phone. Just follow the directions below. No software needs be loaded or installed. Anyone can join and non members are welcome. Details are here:

Ed

AB8DF

Thanks Zhenxing.

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I did the installation exactly as you described, but unfortunately no activity was seen on the screen. I can try again by changing the cable and adapter, but I need to be sure of this; when I open vox, the phone's microphone will be used, right? If so, shouldn't it be a quiet environment?

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From what you described, working with mono band and sound would not be something I would prefer.

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I have a Qmx, I haven't soldered it yet. If I'm going to use my Qmx, will it be enough to make a cable between the OTG cable and the Qmx?

Thank you Gary.?
I used it at home for a long time with a pi 3 and then a pi 4, as you described. I wanted to try my luck because it was portable and I didn't have to deal with too many devices.

I'd be more worried about my food and water supply than

playing Radio Rambo.

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EMP precautions ended up being simplified in the end to

simply disconnecting the antenna that gathers and feeds

the pulse to the equipment.

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And anyway, ham radio would probably be shut down for

some years until it's over just like WW2.

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Invest in some packets of seeds instead ;-)

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--

- 73 de Andy -

I second that!?

I think that you hugely underestimate how many tubes and crystals it would take to replicate the QMX's basic radio functions, even neglecting any of the computer-control interfaces, IQ outputs, etc..

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If you are concerned about EMP events knocking you off the air buy yourself an old Collins S-line or an FT-101 and have at it;? they have a great user interface, too.? Add a model 19 mechanical teleprinter to include RTTY capability.?

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73, Don N2VGU

On Tue, Jul 23, 2024 at 12:27 PM, ajparent1/kb1gmx wrote:

I've also

measured what the SWR looks like when tuning.? You get the

bad states of High SWR as well as switching transient while

relays are doing their thing (moving contacts).

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Likely the worst transient is when the relays switch over between high-Z and low-Z configuration; when this happens it is a dead open, limited only by the loss from the input connector to the changeover relay, which is only a small fraction of a dB.?

As mentioned, a pad or resistive bridge will protect the radio during tuning but then tuning must be avoided/inhibited when they are removed

Oh, and the QMX protection is purely to cut off transmission if SWR is high, it doesn't just 'reduce' power out. It may be too late by then. Lots of other radios scale back power proportionately iin these scenarios, but many QRP radios do not.?

--

73, Dan? NM3A

On Tue, Jul 23, 2024 at 09:20 AM, Zhenxing Han N6HAN wrote:

On Tue, Jul 23, 2024 at 09:07 AM, Glenn W2BX wrote:

On Tue, Jul 23, 2024 at 11:12 AM, Chris KB1NLW wrote:

..."use no more?
than half its rated power during antenna matching. This reduces stress on the final stage".

Correct me if I'm wrong but I don't believe there is any way to adjust power output on the QMX+

?

There is an SWR tune function in the menu. When tuning from there, by default the output power is reduced to 25% (50% of the output voltage). The percentage is also configurable in the protection submenu.

As Zhenzing said, if you ALWAYS use the SWR Tune function when you use the auto tuner, then it's probably okay. However, make sure that the tuner won't retune randomly (the T1 won't). Also, make sure you tune the correct band - the SWR Tune function defaults to the lowest band and NOT necessarily the band you are planning on using.?

And Allison does have a good point!

--

73, Dan? NM3A

Yes the jumper is there

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Martin

DK3UW

Hi Everyone.? Having just successfully built a QDX, with a QMX "on the way", I have a question for Hans and the Group.? The QRP-Labs radios are all fantastic, and Hans is a certified genius.? However, we all live in a very tumultuous world, and the very real possibility exists of our radios becoming useless from an EMP blast (whether man made or cosmic).

?

I would love to build a transceiver, similar to the QMX, but instead of EMP susceptible integrated circuits, step back in time a bit and use vacuum tubes (valves).? A modern radio design utilizing low power tubes instead of ICs.? It would certainly be larger than what we have now, but I'll trade size for heavy duty reliability any day.?

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What do you think?

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73,

Roger K1VB

? ?

On Tue, Jul 23, 2024 at 09:14 AM, VA3CJO - Chris "CJ" wrote:

didn't matter if the chokes were on the radio or antenna end, it worked both ways, though SWR changed slightly)

?

?

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More likely, the SWR?reading changed when you choked off the common-mode currents.

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73, Don N2VGU

I lost count of how many times its been said...

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QCX, QDX, QMX are incompatible with auto tuners.

ALL of the auto tuners go through states of really bad match

while seeking an acceptable one.? Bad being well over 3:1

and as high as 10:1.

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IF you insist, insert a 3DB pad between the radio and tuner

to protect the radio while tuning. once set it can be removed.

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So happens I have a T1 and I think its a great tuner.? I've also

measured what the SWR looks like when tuning.? You get the

bad states of High SWR as well as switching transient while

relays are doing their thing (moving contacts).? ?I ahve more

than a few radios it would be unsafe to use and for those?

a Z-match does the work with the tayloe bridge indicator.

?

--

Allison
------------------
Post online only,?
direct email will go to a bit bucket.

Ah! ?That would explain it. ?I definitely ordered the QLG3 option. I figured I might as well have the option just in case. :)

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Thank you for the response! ?I’m very excited to get started on this one. My last QMX (rev3) build was a pleasure to build and works fantastically.?

Thanks again,

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David Hoskins

WB5GNR