Re: [Elecraft_K3] Output problem on 80 and 160 meters

Rick NK7I

The answer there is to take the USB-Serial device and plug it into EACH USB port on your computer and (via Device Manager) TELL the OS what port you want it to be in each case (the same).  Do this with each of your USB-Serial cables (because they often have a unique ID code) before you actually intend to use them.  In the long run, it's simpler (I got tired of that and went a different route and now use real serial ports).

The utility program can also rescan the available ports to see what shows up, so you can try each one in turn to see if one works for you.  Or scan it with the cable unplugged, plug it in, wait for the OS noise, then scan again and choose the one that was added.

This of course presumes that the serial port on the radio has not been compromised.  A (power off) reboot of the computer (and radio) often clears some issues as well (drivers hang, the OS belches...).

Merry CHRISTmas,
Rick wa6nhc

On 12/23/2015 3:14 PM, Mike Flowers [Elecraft_K3] wrote:
Hi Peter,

Depending what your COM Port 3 is, Windows will sometimes change com port assignments.   

This is often the case if USB/COM port converters are used.  Unplugging and replugging these can lead to this. 

Use Device Manager to determine what COM ports are defined and try them all. 

-- Mike Flowers, K6MKF, NCDXC - "It's about DX!"

On Dec 23, 2015, at 12:42 AM, 'Peter Ravn' fasan5@... [Elecraft_K3] <Elecraft_K3@...> wrote:


I’m stuck in the troubleshooting process, as I can’t connect my PC with the latest K3 utility to the K3. I keep getting the message “Attempting to contact K3 on port COM3”. I’m using Windows and have tried various serial cables, including the original one.

Peter OZ8CTH 


Fra: Elecraft_K3@... [mailto:Elecraft_K3@...]
Sendt: 21. december 2015 11:29
Til: Elecraft_K3@...
Emne: Re: SV: [Elecraft_K3] Output problem on 80 and 160 meters



In 2008 I posted the following which I don't recall ever being clarified and which *may* have a bearing on this thread....


"Been wondering just how the TX Gain calibration works. To quote from the manual - 

"The gain constant is updated whenever the TUNE function is activated on a given 
band at one of three specific power levels: 5.0W, 50W, and 1.00 milliwatt." 

So if I'm adjusting my external ATU by TUNE(ing) at say 5watts, will the (LP)Tx gain constant be updated while feeding into an unspecified load. The described procedure requires the use of a dummy load to set the gain constant; if the load isn't 50 ohm resistive will the constant be set to some anomalous figure which may not be updated when the atu eventually presents (hopefully) 50R to the K3?? "


It certainly appeared to be an issue for me until I ensured I stayed away from exactly 5w when adjusting external ATUs, amps etc as it seemed this would update the low power TxGn settings when the load was far away from 50 ohms resistive and so screw up the gain settings. The same would apply for tuning at exactly 50w for the high power setting - 4.9w, 51w etc should be good.....



Stew, GW0ETF


---In Elecraft_K3@..., <everettsharp@...> wrote :

Recently I was checking the power output on my K3, after changing to the new synthesizer board.  Having completed the transmit power calibration using the Utility program I found that on some bands I had low power output. After spending a half hour, or more, I discovered that I had the ATU engaged. Once I bypassed it everything was normal on all bands. 


So the long and short of this is make sure you have you ATU bypassed when checking your power output when using a dummy load. 


Everett N4CY


On Dec 20, 2015, at 5:59 PM, mikerodgerske5gbc@... [Elecraft_K3] <Elecraft_K3@...> wrote:


Peter, as Bill said, might be the latest firmware glitch. Hope so.

Mike R

Find me on "Zello", a walkie talkie or handi talkie type app. I'm listed as KE5GBC. I'm mostly on late at night.


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