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Sherlock Solves a 30 Year Transmitter Hunt

Created by Sherlock on 2023-01-10


Sherlock Solves a 30 Year Transmitter Hunt, (Rev.B)



This transmitter hunt began in 1987 on a VHF simplex frequency in the United States. The hidden transmitter was always mobile and always playing music.


Violation of   US FCC regulations 47 CFR Part 97.113 (d) and (e).


His transmissions were diligently recorded by several ‘Hunters’ over the years. The hunt seemed hopeless because even the direct surveillance techniques and “Transmitter Finger Printing” were unsuccessful. The first Finger Print of him was made in Sept. 1986 using the technique described in the May 2017, CQ Magazine Article, p. 32.


  • “There is nothing more stimulating than a case where everything goes against you”. Quotation from ‘Hound of the Baskervilles’.


He was known as the “Music Man” because he played unwelcomed music from his car FM radio onto the Ham Band. His operations began to be more frequent in 2015 and new hunters were added to the group.


Once he had an interruption in his travel and some expletive came from a man’s voice. We got his voice on tape.


     "Never trust to general impressions, my boy, but concentrate yourself upon details." Watson, “There are no insignificant details”. Quotation from ‘A Case of Identity’.


Facts: He transmitted from the northern part of the city but only in motion at high speeds (Fast flutter indicating speeds above 40 mph), that meant he was on the freeway. Direction finding bearings always showed his path to be from the north to the center of the city and frequently back again.


His daytime operating times were random so he did not have a rigid 8 to 5 job. His operating days and times were plotted on a calendar to develop a pattern.


He never transmitted from a stationary position, not even stop signs. Once his flutter was slow but constant and we saw (on the traffic cams) that the north bound freeway had heavy traffic. By that we knew he was north bound (going home). The traffic counter showed 2000 cars per hour.


His signals were heard by others 50 miles away so he had at least a 30 Watt radio with an outside antenna. Several secret observation sites were used to scan the traffic on the freeway during his past routine, His car was seen once even though he was not transmitting at that time! Since we knew his travel pattern we were transmitter hunting for him even when he was not transmitting. His transmissions times were about 10 to 20 minutes in length but sometimes occurring only once every 6 weeks.


Several suspect cars were identified because of external whips. These days only about 1% of the modern cars have any whip antenna at all so a VHF whip is easy to spot. Photos were also taken for later review. A list of other hams who were on the air at the same time as the music man was collected so we knew who he wasn’t. These hams were available as ‘approved’ “T Hunters”. A few times his signal went north and then just faded out, sometimes same to the west which indicated that he left the city.


The Final Day: His signals were tracked down south on the freeway, like many times before, but this time they kept going south for half an hour and got very weak. There are very few roads to the south - southwest from the city. Then the music stopped. (There only a few remote cabins in that canyon and this is where there is an access road to a locked secure private location begins). 1 hour later a ham started operating from that southern location on a different frequency.


(We were scanning all other frequencies for such transmissions because he apparently never used the frequency he was jamming). He gave his call sign during his operation and about 1 hour after that activity stopped, The Music Man started up again from the same very weak southern location. The music continued to get stronger and went through the center of the city and north on the freeway as it usually had on other days. Then it stopped.


The allowed us to have a call sign by address/ZIP code directory so we knew where all the hams lived. The QRZ locater for the call sign we heard (Extra Class) showed his home as being in the northeast part of the city. Googling ‘Street View’ brought up the picture of his house and his car was in the drive way. That Car was The One Spotted on one of the Freeway ‘Stakeouts’ with the VHF whip on the rear of the roof !


The Next Step: Sharing this information with the authorities in hopes that the Music Man will soon disappear from the band.


  • “I am not the law, but I represent justice so far as my feeble powers go”. Quotation from the Adventures of the Three Gables.


This article is from the notes of Sherlock but some of the direction finding details (AN/PRD-12) and physical interdiction methods of this investigation had to be censored to prevent future ‘music men’ from avoiding detection.


(I should prefer that you do not mention my name at all in connection with this case, as I choose to be only associated with those crimes which present some difficulty in their solution”, Quotation from the Adventure of The Cardboard Box).


The identity of the City and of Sherlock in this case must remain hidden. This is a real event and some music men are armed.



   Epilogue: Later investigation revealed that the Music Man was transmitting his location all the time on APRS. The APRS Track is stored in the APRS Data Base for 2 years.


Sherlock is monitoring, just waiting for another case.


The Game is Afoot.





Sherlock Solves a 30 Year Transmitter Hunt
That pesky "VOX"?
Re: Sherlock Solves a 30 Year Transmitter Hunt
I would speculate that this individual had no malicious intent but rather his APRS system was flawed and picked up audio from the microphone while underway. Perhaps it was configured only to report positions while in motion and not while stationary.
Interesting nonetheless.
Reply to a comment by : W3WN on 2023-01-11

May I use this in a future issue of my club newsletter?
Sherlock Solves a 30 Year Transmitter Hunt
Is it possible the music man was transmitting inadvertently due to some interplay of his car stereo, speed and his mic key?
For example, I could see an explanation such as his driving knee activating the mic in certain positions.
Regardless, a fun story here. Thanks for sharing.
Sherlock Solves a 30 Year Transmitter Hunt
May I use this in a future issue of my club newsletter?