[Elecraft] KX3 + SignaLink USB noise problems

Tue Jun 23 21:58:53 EDT 2015

Amy, 
I just noticed your signature block. Congratulations!! 

Let me describe what I have done in one iteration of my station configuration. I had used the free version of HRD to control my radio and do logging. I used DM780 which is built into HRD for everything. But, to be honest I just didn't like the feel of DM780 so I switched to FLDIGI and kept HRD. I didn't have, or really noticed, digital interference. I was really careful about the cables I used. 

Later on, and a number of iterations, I switched to Win4K3 for control and spectrum display, but I kept HRD and FLDIGI. All my connections are with a cable to ACC1 for rig control and read out, a USB connection for the SignaLink, a cable for the mic of the KX3. Everything else is done with virtual com ports created by com0com where no real cable connection is needed. 

As I can now see the spectrum, I can see all manner of things. I have a house full wall worts, or equal, so I see a number of these. There is some noise created by my laptop which I can hear when my hard drive spins up; that tells me my grounding is not as good as it should be. But, I don't seem to be having a USB created interference problem. I believe I have two things going for me, luck and a set of good cables. 

Lastly, radio control of the KX3 by FLDIGI is necessary or it wouldn't have been included in the application. You can do as I do or as you are trying. So, let me suggest that you pull one cable at a time and try and determine which cable it really is, like trying another USB cable to the SignaLink or using ferrite. I know how frustrating these things can be, but in the majority of cases, the problem can be knocked down to the point of being liveable. Good luck. 

73, 
Barry 
K3NDM 

----- Original Message -----

From: "Amy Wilhelm" <netcrusher88 at gmail.com> 
To: k3ndm at comcast.net 
Cc: "bs usb" <bsusb at k5dkz.com>, "elecraft" <elecraft at mailman.qth.net> 
Sent: Tuesday, June 23, 2015 8:45:01 PM 
Subject: Re: [Elecraft] KX3 + SignaLink USB noise problems 

Yeah, fldigi doesn't seem to know what to do with I/Q. Yet. 

CAT control isn't strictly necessary. But it's nice to have with fldigi, WSJT, and various logging software. 

73 
Amy 
K3ISI (granted today) 

Sent from infinite squirrels at infinite keyboards 

> On Jun 23, 2015, at 5:18 PM, k3ndm at comcast.net wrote: 
> 
> Guys, 
> Two things. First, you can't use the I&Q data on the KX3 to transmit and I'm not really sure you can use it with FLDIGI; I believe FLDIGI only expects audio. And second, I'm not sure why you need to use ACC1. The only connections you should need to use is to the KX3 mic and the USB connector for the SignaLink. The SignaLink will key the radio with out needing other connections. This may help some of the noise problem. 
> 
> 73, 
> Barry 
> K3NDM 
> 
> ----- Original Message ----- 
> 
> From: "bs usb" <bsusb at k5dkz.com> 
> To: "elecraft" <elecraft at mailman.qth.net> 
> Sent: Tuesday, June 23, 2015 5:01:45 PM 
> Subject: Re: [Elecraft] KX3 + SignaLink USB noise problems 
> 
> With the I/Q output from the KX3 and fldigi software on the Mac why do 
> you even fool with signal-link? 
> 
> Amy Wilhelm wrote: 
>> Yes, it's another post about that little interface we all love to hate... 
>> 
>> I went through archives and didn't find anything that *quite* matched 
>> this, so I wanted to know if anyone's experienced it or has tips. 
>> 
>> Aside from the widely reported high noise floor (it *seems* to be 
>> possible to just crank the RX volume to get past that a little) I have 
>> a couple of symptoms that are...strange at best: 
>> 
>> 1. If I have the KX3 connected to my laptop via the KX3USB cable to 
>> ACC1, and then attach the Signalink to a different USB port, I 
>> immediately experience broadband noise. Changing the IF doesn't seem 
>> to help this, and I seem to be tuning past peaks of noise all across 
>> the band. If I detach the Signalink, most of these symptoms go away (I 
>> think some of the peaks are just out there). 
>> 
>> 2. The Signalink seems to be radiating a significant amount of QRM - 
>> or the cables connected to it (but not necessarily to the KX3) are. 
>> Because I use an Alexloop, my antenna is always right next to my 
>> laptop, interface, radio, all that fun noisy stuff. Conveniently 
>> magloops have this great null directly perpendicular, so I've worked 
>> out that turning my antenna perpendicular to the Signalink - not 
>> necessarily my laptop or radio - reduces the noise floor significantly 
>> (both wideband noise and weird little blips every 150 Hz or so). I'm 
>> not actually sure at the moment whether I've checked if unplugging my 
>> Signalink makes a big difference, but evidence would suggest I should 
>> try that. 
>> 
>> This is all with the KX3 operating off of a gel cell (so no QRM 
>> there), the Signalink with the official KX3 snap-in jumper board and 
>> cables, a Macbook Air running from its internal battery, an Alexloop, 
>> and the included KX3USB cable. 
>> 
>> Any help would be much appreciated - I've seen the page suggesting 
>> some mods to the Signalink and I'm more than willing to do those if 
>> those would help with the symptoms I've been seeing here, but wanted 
>> to check if anyone thought that was reasonable (and that my diagnosis 
>> is) first. 
>> 
>> 73 
>> Amy Wilhelm 
>> WN5FIZ 
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