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Hmm, apparently it can be made to work, but what’s it good for?

I'm with Hans with this.

In order to build a valid simulation you have to know what you are doing?
if only to know if the sim tool fed you trash.? ?So you need to know what you
want and what is a valid result.

Typically you model, build and test to see if the model is valid for each
functional block.? Eventually you have enough block to make something go.

I do better than 90% of design using calculator (or slide rule) and my knowledge.
The exception is antennas as tools like EZNEC or my favorite 4NEC2 (also free!)
As it now only does the same evalutation as EZNEC but it has an optimizer
that once learned can do some slick tricks.

LTSpice is a very good tool but for RF you have to have all the parameters
and vaild models.? Also there is the free, student, and professional models
of the program. The student is not outrageously expensive and the professional
version can make your eyes bleed.? There is also Genesys, I think the company
was paying 6K$/year for that.

There are no software sims that can do " I wanna build a radio" and spits
out a design.

--
Allison
------------------
Post online only, please no email.

Some of the older Touch-Tone? keypads? (mid-'70s) would somehow generate the two tones simultaneously using only a single transistor.? And the Bell System frequency and amplitude matching requirements were pretty tight.? I never figured out how it was done....
73, Don N2VGU

With a red face I have to pass this along.?

I have built countless transceiver kits from both QRP Labs and Elecraft (K1&K2’s). I have never had a “problem” before the QMX I am building now.?

I had very low power output. After days of playing with the LPF I was ready to put it on the shelf for awhile.?

One last idea I reheated all the toroids. That did the trick I now have 4.7. - 5.1Ws on all band with the 9volt build.?

I had check all the connections with a meter but must have missed something.?

Now I’m patiently waiting for Hans to work his magic on the firmware updates.?

Larry NA0F

Hi,

I would first try to search for a "QMX" topics in a Search square of this group.
However, the FW is still in Alpha phase so the info is far from complete yet.

73 Bojan S53DZ

Hi Kees,

There are some interesting documents out-there but dont know if they are for QCX mini.
I suppose you should contact Martin DK3UW directly:
/g/QRPLabs/topic/multiband_qcx/86392526?p=

73 Bojan S53DZ

--Has anyone built or used one of these yet?
I'd like to know about it's performance before moving forward.
Wayne S.
KF7RCM

I just can't stop myself!
--
72,
Bill, N4QA

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I have the QDX and QMX Transceivers (still under development) with the much higher functions but also a small "pile" of single band QCX Mini's which I would like to "multiband".

73 Kees K5BCQ?

Does someone have a link to the above design ? Maybe it was just for the "standard" QCX+ ? Are there any other QCX-Mini Multiband designs out there ?

73 Kees K5BCQ

Hans I much prefer your more detailed March 3, 2022 explanation: --
73, Rick
VE7TK

Website:

On Tue, Jul 18, 2023 at 03:09 PM, Hans Summers wrote of G3RJV:

George once explained “why QRP”, he said: “Because it is a hobby we don’t have to do it - or mean anything - or fit into the world plan. As long as you can do one useless thing a day - life still has some meaning and that is the essence and the joy of life”.

Spot on!

It all gets absorbed and then one day , maybe a week or 30 years it suddenly provides
an answer to a problem, or a building brick.

That's why I'm forever reading decades old radio or electronics mags.
?
--
- 73 de Andy -

Yes, patience is required indeed!? My latest (small) order was actioned by Hans in a day or so.? TNT then sent me an email saying "Collecting" on 10th July. It remained at the same status for precisely a week.? On 17th July the status changed to "In transit" and today (18th) it has reached Istanbul.? From past experience, once it gets on a plane to the UK, things happen pretty fast!? Here's hoping!
--
Peter Lee
G3SPL

RR,
?I vote for a 40-15 version as well. But I would take a high band one, too. Right now I'll be very happy to see the next firmware version!
--
73, Dan? NM3A

I'm just finishing up my build on a QCX+ 20m.
On page 52 of the assembly manual it mentions R50, the 270 ohm resistor being "larger than the other resistors" obviously a higher wattage rating.
... but the one provided in the kit looks exactly like all the others, (1/4w?).. same with the 270ohm R48 on the front panel..

Maybe this is a leftover comment from a previous rev of the manual?

??

Seems to be a complex subject. Anyway I could fix and replace the damaged parts. Burning one BS170 always needs to replace all. And testing the output of the 74act gate also made clear that it was destroyed too. I could substitude it and the tx works again. Anyway I will install zwo zener diodes as soon as possible. I'll let you know about my experience. You can Only test the burning point of a BS170 one time ?. So the best way to decide if a protection works is the experience of other Hams. A? trx with permanent tx for 12s or even longer (wspr) normally should not transmit in full power, when it is designed for CW or Ssb. In this case I'm with you.
Diving a car you can prevent injuries by driving slowly (low power) and a seat belt (protection of the p. A) . But even if you are a safe driver, a part could fault.. ?.
72 de Natt
DL1SER

Thanks everyone for all of your replies.? This is some good information to mull over.? I'm curious if anyone has built a 40/20/10 variant.

Thanks all,
73,
Jon
KJ4CRW