Hans,

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Thanks for the update!? Hope you had a Merry Christmas.??

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Brien - KE7WB

What are y'alls recommendations for on how to increase output to 10W on 80 -10m using outboard amplifier using existing kits?? QRP SSB is generally considered 10W so I want to get there with the QMX+.

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Dale Hardin
KS4NS
Elberta, AL

Hi Group,

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Here is a thread with info on the Smart Power Attenuator (SPA). ?They are in stock and available for immediate shipment.

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Now that I have finished and released firmware version 2.0, I will turn my attention to creating and publishing online info on the SPA.

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?

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Robert, WA2T

I'll commit to one (possibly two) if there's another group buy.

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Mike, W9LG

With the latest version of the firmware it is no problem.

Cal,

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Now that you have ordered the PCBs, can you please point us to the correct BOMs LINK to use for Digikey and Amazon.??I purchased my Digikey and Amazon parts from a previous BOM listing 3-4 weeks ago and need to cross-check what parts changed or I am missing.? Also please point me to the current Build Instructions LINK, too.

I mailed my check on Dec 23.

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Happy New Year.

Glen, WB4KTF, Austin, TX

Regarding the QMX get the build instructions out, look through, understand and follow the schematic / circuit from 5351 to the PA transistors in 'transmit' to see if DC Voltage is getting to the PA transistors (Centre, top and bottom? Taps T501 primary)? and use a multimeter to see what is coming out of the driver IC' (IC502 and IC503) on transmit.? Will be an AC/RF signal but should read as a few volts of DC on transmit with a multimeter

Merry Christmas everyone!

Reheat T501. ?I had same problem. ?I don’t think that the QRP Labs scrapes any of the toroids wires and depends on the solder to dissolve the varnish. ?It took quite a while and higher soldering iron temperature until I was satisfied that the solder was adhering to the transformer wires. ?Everything is working fine now. ?It’s quite a fine rf tool at a reasonable price, even after paying them to build it.

We had thirteen folks at the 19 December Michigan QRP Club weekly Zoom chat. Please join us Thursday 26 December (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. New hams are encouraged to participate and ask questions. 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:

Thursdays topic will be a review of ham radio gifts received over the holidays and the Michigan Mighty Mite transmitter.

Pete WK8S

Dave N8SBE

Ed AB8DF

Ernie W3ETE

Stan WB8QJZ

Stuart M0SGV

Steve KE8KF

Mike K7FZD

Jacob N3JU

John M7FZC

Casey KC9IH

Neil N9NL

Yvon AE7YD

That big radio space dish in Puerto Rico collapsed. Pete talked about his K1EL transceiver kit the Open QRP 40. He has just finished it and made one contact. Needs to tweak the sidetone level. Latest QRP Quarterly has a 30 meter DC receiver project. Ed will be continue his CW practice now that he is back from Egypt.

John is using his balcony with a new ATU URT1 tuner.

Santa came early to Erie’s house with a KXH-1 . He is thinking about different antennas to use with it. Including a 22 ft zip cord antenna using speaker wire.

Both Pete and Ernie got new paddles.

Casey is waiting on a new High Gain Vertical. It has been bouncing around the country.

The topic for December 26 will be an open forum for any questions, a quick review on holiday gifts and the Michigan Mighty Mite. Anyone can take the floor and ask questions. We will go one by one until all have had a chance to have the floor. Files, pictures and presentations can be shared if you have any. There will be time for comments and questions. Please try to stay muted when someone has the floor.

Thanks

Ed

AB8DF

Depending on the quality and brand of power supply and what happens when it sees a load of RF coming back down its cable that's definitely a potential issue . .? ?

(50 years experience has taught me that good branded RF proof power supplies are a good use of money.? ?e.g. Pull the top of? a MeanWell professional market 'Mobile radio /base station power 13.6V supply and count the components not in the Chinese look-alike that's a quarter the size and 1/10th the cost)??

I'd fix the QMX, put the BUC supply on the naughty-shelf and see what happens with a decent supply and a well fitting plug . .?

Just an idea: Maybe there are power-supplies that don't like HF and change (increase) their output-voltage.

What type of BUC did you use? imho you are not the first, who's QMX died using a converter.

73, Wolfgang

Using the same power supply (11.8v via BUC converter) and same antenna (Resonant 40m) that had been working for an hour, suddenly the unit quit putting out RF and when I put my hand on it it was very hot.
Disconnected power of course, and verified the SWR was still 1.3 on the 40m antenna.

This is an assembled unit from QRP-Labs.

I've done a reset via the menus, and let it cool overnight, no overheating now, but it's drawing slightly more current (0.12 increase to 0.24) at idle, and doesn't draw anything more at transmit.

I don't know where to start.

You are obviously free to go and build what you want, but there is no practical difference on air between 3-4W and 10W. I would get on air and make a few dozen contacts in the time needed to get a 10W amp shipped and delivered.

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My2Cents

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72/73? de Enzo M0KTZ

Just a hunch...? The BS170s seem to? be the most sensitive, at least to power levels ... maybe heat too. Nothing like FT8 to generate heat.

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72 de N4REE, Bob Easton - QRP CW forever

?I run wsjtx and a raspi to my QDX and it started having similar problems. I found wspr would tx ok using my laptop but no longer on the raspi, just a brief transmission. Anyway, I found out that must have been after an update on the raspi, the sound card level was running at 153%. As Hans usually says set tx audio to max, I did not discover for a long while that reducing the tx audio level from the raspi back down to 100% cured the problem.

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73 Ken g4apb?