40 m dead carrier curiosity

[radiozed]

This past weekend I took the family out to the country where I had rented a quaint turn of the century (19th century) farmhouse out in the middle of nowhere.  Nearest neighbor a mile away, no Internet or television, no cell phone coverage...it was a great few days of unplugging from everything and forcing the kids to tune in to, you know, reality.     One of the few tech things I brought along was my Grundig radio so I could do something I haven't in a very long time...some SWL. 

While scanning the bands one night, I came across something odd in the 40 meter band.  It was a dead carrier that pegged the Grundig at S9 and it ranged from around 7200 khz up to 7300 khz (I didn't make a note of the exact start/stop).  It was there the entire 3 days we were at the farmhouse.  That makes me think it was coming from somewhere in the house (or out in one of the barns that were on the property) as opposed to some area Ham who had inadvertently left something keyed on their rig.  It was an absolutely silent carrier, no hint of background noise, no static, no tones...nada. 

Anyway, I was curious what would cause something like that.  I've never experienced a signal like that before when SWL.  Maybe it's a phenomenon some here are more familiar with. 

[redhat]

Could be a birdie in the receiver itself.  Sometimes funny things happen to rigs when they get transported.  Unless you heard it on another radio, that would be my guess.

+-RH

[Pigmeat]

The early Sangean 909's had a birdie at 17885. They were nice enough to to notify you about if in the manual, a lot of companies don't.

[radiozed]

Interesting.  I certainly hadn't thought of that.  When I turn it on now, however, I don't have it.  Maybe the birdie got knocked out of it on the long drive home.   

[BoomboxDX]

Anytime I see dead carriers or other such anomalous signals I think of RFI. Maybe the house, or nearby houses had a computer running? Maybe a switching power supply to run their cordless telephone? Some of the power supplies put out RFI.