开云体育

ctrl + shift + ? for shortcuts
© 2025 开云体育
  1. QRPLabs
  2. Topics

No Transmit

 

开云体育

Received a new factory assembled QMX+. Testing with a 9 volt battery.? This is a 12 volt QMX+. The receive is excellent. However, there is no transmit on any band.? Tested into a dummy load with a scope attached.? when operating the key there is nothing.? The factory Doc indicates all bands transmitted well.? Any thoughts on where to start?

Tnx,

Tom KT4XN
 

First checks:
1) do you have the QMX+ in CW mode?? It will not react to the key in Digi mode
2) does a 'P' or an 'S' appear on the display after the frequency?? If so, you are in Practice mode or the SWR protect has triggered, and in either of those cases transmit is disabled.? Practice mode can be disabled via the menus, and if SWR protect is triggering, you have a connection problem with your dummy load.
3) what kind of a 9V battery are you using?? The QMX+ will draw about 1A on transmit, and if you are using a standard 9V alkaline battery, it may be dropping the input voltage very low while trying to transmit, giving a very low output power.? You can see what voltage the QMX+ sees if you set the display option to show the battery voltage.? Then monitor it during TX to see what is happening.
?
If none of these quick-checks is the problem, we have to dig deeper.
?
Stan KC7XE
 

开云体育

Stan, Guess I won the dummy award of the year on the 1st?day.? The QMX+ was in Digital mode.? Set it to CW and all is well!

Tnx,

Tom KT4XN


From: [email protected] <[email protected]> on behalf of Stan Dye via groups.io <standye@...>
Sent: Wednesday, January 1, 2025 3:21 PM
To: [email protected] <[email protected]>
Subject: Re: [QRPLabs] No Transmit
?
First checks:
1) do you have the QMX+ in CW mode?? It will not react to the key in Digi mode
2) does a 'P' or an 'S' appear on the display after the frequency?? If so, you are in Practice mode or the SWR protect has triggered, and in either of those cases transmit is disabled.? Practice mode can be disabled via the menus, and if SWR protect is triggering, you have a connection problem with your dummy load.
3) what kind of a 9V battery are you using?? The QMX+ will draw about 1A on transmit, and if you are using a standard 9V alkaline battery, it may be dropping the input voltage very low while trying to transmit, giving a very low output power.? You can see what voltage the QMX+ sees if you set the display option to show the battery voltage.? Then monitor it during TX to see what is happening.
?
If none of these quick-checks is the problem, we have to dig deeper.
?
Stan KC7XE
 

Tom,
?
You're in very good company. I just did exactly the same myself with my new QMX+ that Santa brought me! Just finished the construction this afternoon and I was gutted that there was no response from the key at all.?
?
I'm glad that I saw this post before rolling up my sleeves and getting the test equipment out! Thanks!
?
73 and Happy New Year to all.
?
Ellis
GM4GZW

1 - 4 of 4