Knock knock sound while listening to transmissions

[Tidycat]

Greetings all. I'm new to GMRS and just got my FCC license a few days ago so this may be a dumb question... when I'm listening to other folks on any of the channels there's a repeating knock-knock sound during transmissions. Is this normal, and is there a setting that turns it off or is it a standard part of GMRS? Radio is a Tidradio GM-5R.

Thank you.

[SteveShannon]

10 minutes ago, Tidycat said:

There's a cell tower about 450 yards from the property here. I get the knock-knock/tick-tock/heartbeat sound on both radios no matter where I go on the property so that seems like a likely source of the interference.

It's really difficult to know what it is.  It could be something on the power lines, or part of the cell site.  It could also be a motor controller somewhere, such as on a pump, or a power supply for some equipment you have.  A lot of times hams will turn off the power to their homes to see if such interference continues.  Then they turn on each breaker until the noise begins again in an effort to determine which circuit it's on.

Also, go somewhere else, distant from the cell tower, and see if the sound persists.

[SteveShannon]

2 hours ago, Tidycat said:

Greetings all. I'm new to GMRS and just got my FCC license a few days ago so this may be a dumb question... when I'm listening to other folks on any of the channels there's a repeating knock-knock sound during transmissions. Is this normal, and is there a setting that turns it off or is it a standard part of GMRS? Radio is a Tidradio GM-5R.

Thank you.

It’s not part of GMRS. It sounds like it is probably just some kind of interference. Since it’s rhythmic I would guess it’s some piece of electrical equipment somewhere. 

[Tidycat]

55 minutes ago, Sshannon said:

It’s not part of GMRS. It sounds like it is probably just some kind of interference. Since it’s rhythmic I would guess it’s some piece of electrical equipment somewhere. 

There's a cell tower about 450 yards from the property here. I get the knock-knock/tick-tock/heartbeat sound on both radios no matter where I go on the property so that seems like a likely source of the interference.

[Tidycat]

2 minutes ago, Sshannon said:

It's really difficult to know what it is.  It could be something on the power lines, or part of the cell site.  It could also be a motor controller somewhere, such as on a pump, or a power supply for some equipment you have.  A lot of times hams will turn off the power to their homes to see if such interference continues.  Then they turn on each breaker until the noise begins again in an effort to determine which circuit it's on.

Also, go somewhere else, distant from the cell tower, and see if the sound persists.

Thank you sir for the helpful advice. I'll try turning the pump off which is the main power consumer here.

[SteveShannon]

3 minutes ago, Tidycat said:

Thank you sir for the helpful advice. I'll try turning the pump off which is the main power consumer here.

please let us know what you find.

[Tidycat]

1 hour ago, Sshannon said:

please let us know what you find.

Haven't had a chance to venture away from the property yet but my Nagoya 771G whip antennas just came in and the interference is gone now.

[SteveShannon]

25 minutes ago, Tidycat said:

Haven't had a chance to venture away from the property yet but my Nagoya 771G whip antennas just came in and the interference is gone now.

That’s interesting. I can’t think of why that would be. 

[Tidycat]

4 minutes ago, Sshannon said:

That’s interesting. I can’t think of why that would be. 

Seems odd to me too. At least the issue is resolved now. Thank you for your responses.

[WRXB215]

@Sshannon, @Tidycat, is it possible that the other antenna wasn't screwed down tight and was moving slightly?

[SteveShannon]

1 hour ago, WRXB215 said:

@Sshannon, @Tidycat, is it possible that the other antenna wasn't screwed down tight and was moving slightly?

On two different radios?  Yes it’s possible. 

[Tidycat]

The standard rubber duckies on these Tidradio GM-5R's have a hex set screw mashed into the threads on the radio. They were very tight and I was actually afraid I might strip out the hole getting them loose to mount the Nagoyas, so I don't think that was the problem. And both antennas were screwed down tight.

[Tidycat]

I'm listening to a nice GMRS presentation on the 462.700 100.0 repeater here in Vegas and one participant's transmissions have the tick-tocks while all the others are free and clear. Not sure what's causing it but before every transmission with the rubber duckies had the tick-tocks.

[SteveShannon]

It might be interesting to see if putting the rubber ducks back on results in the issue returning.  If so, maybe it’s just a design flaw with the antenna.