MMRA logo View of Boston from Quincy Site
© 2006 Minuteman Repeater Association 


The 146.61 MMRA repeater has been plagued with interference since approximately March of 2005. The signal is a wideband (500kHZ+) buzzing sound, on for 1 second, off for 1 second. On a spectrum analyzer, it looks like spread spectrum data. More information about the signal in PDF format.

You can hear the signal for approximately 1/4 mile around the '61 site. It emanates from a residential neighborhood near the repeater.

IMPORTANT NOTE: We DO NOT need any help in direction-finding this signal. We have isolated the source on three occasions to within twenty feet. What we need help with is identifying the type of device that is generating it, and determining just how widespread a problem it is. We believe it to be utility related, but work by both the cable operator and telephone company has not eliminated it. (The power company is next).

We have found similar signals in other parts of Marlborough and Northborough on slightly different frequencies. Off of Farm Road in Marlborough, there is another source at 143Mhz, and two sources at the east end of Northborough on 143 MHz and 152 MHz.

We have audio/video captures of the signal from the club's service monitor here:
Time Domain Scope - 900 Kb
Frequency Domain Scope -- 3.8 Mb

Can you identify this signal?

Can you find places in your town with the same type of signal?
For best results, set your receiver to AM mode and tune through 140 - 155 MHz. If you don't have AM mode, use Wide-FM, or open the squelch on your standard narrow FM receiver.

Be a hero! Help the club determine what this is so we can put an end to it!

If you have any comments or would like to report another source, send email to