The ‘sticky needle’ phenomena is one that’s haunted some ham and citizens band radio users for decades and continues to do so.
“What’s a ‘sticky needle?” you might ask.
Well normally the needle in a CB or ham radio’s analogue signal meter wave ups and down to indicate the strength of a station’s incoming audio.
With a sticky needle, however, the needle either behaves in a lazy way by not getting as high as it should or, in a worst case scenario, doesn’t move at all (i.e. it’s stuck to the floor of the meter).
Whilst sticky needle syndrome doesn’t negatively impact the TX or RX performance of the rig, it does complicate operations in a number of different ways…
Firstly, the operator who’s rig suffers a stubborn moving needle is unable to return an accurate signal report.
Instead, he must provide a guesstimate of the signal strength and take the risk of being out by 1 or 2 ‘S’ points.
This might not seem like a big deal, but to those ops who rely on a RX precise report on how well their station is working, it’s like receiving counterfeit money for Christmas — i.e. it makes you feel good if you don’t know it’s counterfeit — but try and spend it and you’ll find out it’s worthless.
A second negative of having a sticky needle is that you don’t have a true gauge on the strength of propagation in general.
You can’t compare it against previous band conditions; you can’t make formal judgements about which region is coming in better; and you can’t evaluate 2 rival stations if requested to do so — other than giving an opinion on who ‘sounds louder’ than who.
As we know, though, a station who sounds ‘loud’ might not necessarily have a great signal.
Causes of a Sticky Needle
A number of different reasons are put forward by hobbyists as to what might make a signal needle inoperative.
The first is high humidity in the shack and how it interacts with the signal box — an issue particularly relevant in tropical environments such as on small Pacific islands.
As you’re probably aware, humid WX makes the air thicker than usual.
One suggestion is that air with high moisture content can penetrate the meter and make it sticky inside, thus preventing the needle from moving freely.
Even when dry, the moisture has mixed with tiny particles of dust and chemicals inside the box to create an inhibiting glue-like effect on the movement of the needle, thus giving the impression of being lazy or sticky.
Apart from muggy shack conditions, another possible reason for a malfunctioning signal needle is that the fulcrum at the base of the needle is worn or dirty.
An effective strategy used by watch makers if a watch hand is dirty, and provided you can open the meter, is to suspend it over a container filled with white mineral spirits for a few days.
Apparently, the vapors of the spirits act as a lubricant, releasing the build-up of grime and enabling the defective needle to move freely again.
A third possibility of a faulty needle is that the screw securing the fulcrum is either too tight or too loose.
With the radio off, just gently move it until the needle drops back to zero and it should be right.
Make sure you don’t loosen the screw too much though or the needle will fall off its axis and you’ll need a really steady hand and good set of eyes to put it back on.
Hopefully, this article has provided some insight into the mysterious ‘sticky needle’ phenomena.
Like a nasty hemorrhoid, you can put up with one for a while; but eventually it becomes uncomfortable and you start thinking about a finding a solution.
My advice is to try one of the strategies above and hopefully then your sticky needle will find a new burst of life!
73 de Darren, 43DA001
Leave a Reply