[time-nuts] Can a Trimble Thunderbolt cause QRM? Noise can be seen remotely via my SDR.

[Chris Wilson]

Hello to those that replied off group.

 Tuesday, January 12, 2021

  Many thanks for the replies, Time Nuts always confuses my mail app and I have to check if replies are from an individual or via the reflector.

I eventually tracked the culprit down today. Getting on site and turning off all the power, and using a battery powered receiver saw no change. I was mortified. Nonetheless the stability and strength of the interference still had me believing it was very localized. It was then I started thinking of any battery powered source with a 10 or 20MHz reference in it. My race truck has a GPS tracker in it. It's internally battery powered when the ignition is off... I turned it on at the end of the season when the truck went into hibernation. I opened the truck and was reminded the tracker had a USB cable pig tail for connection to a PC for setting up attached and strung behind its hiding place. I removed the USB cable from the GPS unit (a quality make, not some Chinese clone)  and went back to the receiver in the house. The noise was gone!!! For kicks I reconnected the USB data cable and the noise was back again. So thanks for the suggestions, all these modern gizmos we surround ourselves with, it's no surprise many suffer huge noise levels! All the best and thanks again!



Best regards,
 Chris        mailto:chris at chriswilson.tv




CW>   12/01/2021 23:21

CW> I have had a sudden occurrence of interference on all my HF
CW> receivers / transceivers recently.  I cannot gain access to the
CW> remote location where they are and am operating them remotely at
CW> the moment. At the site is my Trimble Thunderbolt and it's been on
CW> permanently for several years with no apparent issues. It feeds a
CW> divider by David Partridge. I am wondering if the TB could be the
CW> source of the QRM in some way as it's bang on 10MHz. I no longer
CW> see WWV but a very loud noise on all receivers on 10MHz, 20MHz and
CW> 30MHZ. If I zoom right in I see what looks like FSK on the signal.
CW> The spurs are all over the place and particularly bad, if they are
CW> indeed spurs of the 10MHz noise, around 21 MHz.

CW> Would some Sherlock Holmes who is familiar with remote operating
CW> a Kiwi SDR receiver have a look around and tell me if they think
CW> the TB could have gone berserk in some way please? I can't think
CW> of any other 10Mhz source at the location. Thanks and a belated
CW> happy and healthy New Year to all.

CW> The Kiwi can be accessed at:

CW> http://82.70.254.222:8073/