We are all aware that everyday household equipment causes interference with our scanning hobby and try to eliminate most of it, but if you have a signal you just cant fix maybe this is a case of radio scanner birdies.
Birdies is the name given to unavoidable signals generated from within the radio itself that will always be there as these are required to make your shiny scanner work.
Identifying a Birdie
My first step in trying to identify an annoying birdie is to do a quick internet search along the lines of “make+model birdie frequencies”, this could really save you a lot of time as scanner makers often include the frequencies in documentation or someone else has already marked this signal as a problem.
If nothing is found in the internet search about the unwanted signal then its time to start eliminating other possible sources of this interference by taking some quick and easy steps.
Unplug the Scanner Antenna
Taking the antenna out will wipe away a huge amount of interfering signals and will give you a great idea if it is your set or something close by causing a problem.
Power Down all Other Equipment
If pulling out the antenna didn’t fix it then leave your scanner on the frequency so you can still listen to the offending signal and start to switch off every other electrical item you have where you are using your scanner, we like to do this one piece at a time and leaving a few seconds between each to let them completely drain of power and shut down properly.
For a good idea of what equipment could be causing the problem please read the list below.
Worst Offenders for Generating RF Interference
Computers and Computer Screens
For many having a computer in the shack is essential either for decoding radio data modes or logging frequencies but these are the number one causes of unwanted signals, due to the very nature of their design they emit so much interference over a wideband and this is always the first thing we power down.
If you are using a computer for decoding of signals there is plenty of free downloadable software that will run on older computers which will cause less interference and can be bought very cheaply these days. As an example we use a 200mhz PC with free software that will happily decode RTTY and other data modes while giving us very few stray signals.
Televisions and Plasma Screens
Another nightmarish source of radio signals are televisions and your radios don’t even have to be that close to experience a problem and sometimes even a TV churning away in another room can cause interference.
Other Radios and Scanners
Mounting radio equipment directly on top or next to each other will cause problems as the birdies from one radio can be easily picked up by the other.
Even with a good degree of spacing between sets you will still have a small degree of problems so a little thought on how your stack of radios is placed can reduce these to an acceptable level.
Cant do without them but they do put out more than a few strong RF signals so always try to place them as far away from your radios as possible.
Badly Designed or Poorly Modified Radios
When a radio is produced new every effort is made to reduce the amount of interference it will cause to itself and these birdies are almost always known but problems can occur when radios are “tinkered” with.
With the amount of information available to tweak or add new functions to almost every radio ever made some secondhand sets have been modified by people with the technical skill of a 4 year old (apologies to any 4 year old prodigies reading this).
Even something as simple as not grounding an oscillator circuit will turn it into a transmitter powerful enough to screw with every other radio in your shack.
If you think you may have a radio that has been messed with then try and find someone who knows what they are doing and ask them to take a look at it for you. The same goes with badly designed radios as sometimes there may be a few simple fixes that will cure any design flaws for good.
Signal Still There?
If you have followed the steps above and the signal is still there then you may have a birdie, if you have another scanner that can pick up the same frequency use this to check for the signal as well. If there is no signal heard on the second set with an antenna plugged in then the problem is almost certainly with your original scanner.
If your second scanner is also picking up the rouge signal then its time to look at you local environment again and possible causes of interference.
Please don’t drive yourself crazy in tracing these signals as it could be a faulty power supply two houses away, do your best with local equipment and if the problem is still there try to live with it.
By following these steps you should quickly get to the root of the problem, thankfully properly designed equipment will generate very few birdies and once you know where they are its easy to work around them.
Bananaquits photo courtesy Wikipedia