Motorboating

[Algod]

So I got my SDS200 about 3 weeks ago, and find it to be a great scanner. The only issue that I seem to have is some motorboating on a few of my conventional channels that I don't get with my 436HP. I've tried to use IFX, but that doesn't seem to have any effect, nor does adjusting the squelch. Haven't ventured into filters yet. Can't find much info on what they may, or may not do. Does anyone have any thoughts to mitigate the motorboating.

 

[Whiskey3JMC]

What exactly do you mean by "motorboating"? Is this digital emissions on an analog channel?

 

[Algod]

Sounds like a machine gun, or jack hammer in the back ground.

 

[fxdscon]

Sounds like a machine gun, or jack hammer in the back ground.

What frequencies specifically?

.

 

[nd5y]

Sounds like a machine gun, or jack hammer in the back ground.

It might be intermod from a digital signal. If that's the case there is probably nothing you can do about it.

 

[Whiskey3JMC]

Is there analog traffic from the agency you intend on hearing? If not they could have switched modes or less likely using mixed modes. Another possibility is a different agency is transmitting on the same or an adjacent frequency (+ or - a few khz) using a digital mode (DMR, NXDN, P25, etc) causing intermod. Filters only apply to the digital modes but for an analog conventional channel that doesn't have tone squelch set (CTCSS, DCS) you could try setting the modulation to NFM. Hold on that channel, hit the "E" key, choose Edit Current Channel. Scroll to Set Modulation and choose NFM. You could also try setting the attenuator but this may degrade the station you intend on hearing. If these steps don't mitigate the issue and it doesn't go away after connecting a weaker antenna, there may not be a way to deal with it. It's all about experimentation

 

[Algod]

Somerville fire disp 483.3875 131.8
Wakefield PD 476.7875 131.8

 

[Whiskey3JMC]

Wakefield PD 476.7875 131.8

I see a Wakefield license showing P25 emissions here, it's 2 mhz below the frequency you gave though at 474.7875. Are you sure this isn't the correct frequency, I'm not seeing any results for 476.7875

 

[fxdscon]

Somerville fire disp 483.3875 131.8
Wakefield PD 476.7875 131.8

Wakefield PD is 471.7875

I'm currently local to those areas and recieve both analog with no motorboating background.

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[Algod]

Changed FM to NFM it didn't seem to help.

 

[a417]

I just looked at Wakefield PD's ULS listing, and they have 8K10F1E & 8K10F1D listed on 471.7875 (I don't see an 476.7875), so they are licensed for digital, they probably have the equipment to support it, and you're most likely hearing them in mixed mode. Some Analog voice, some digital.

 

[Whiskey3JMC]

Scratch that, you're probably tuned into an input channel. Try 471.7875 with and without the PL, see if you get analog & P25 transmissions. If you have it programmed in a favorites list you'll also want to make sure audio type is set to "All" so you can pick up analog & digital on that channel. If you do hear both, perhaps it may be best to program it twice, once with the analog tone and the second time with the P25 NAC

 

[a417]

Scratch that, you're probably tuned into an input channel.

Their input appears to be licensed @ +3 mhz , not the old standard +5 mhz.

 

[Algod]

I miss read my note Wakefield is 471.7875

 

[Algod]

Sentinel does not show it as P25

 

[KevinC]

Their input appears to be licensed @ +3 mhz , not the old standard +5 mhz.

T-band has always been 3 MHz.

 

[Whiskey3JMC]

I miss read my note Wakefield is 471.7875

Makes more sense now. Try my above on that channel, let us know if you hear analog & digital

 

[tvengr]

If it is indeed motorboating, that is normally caused by the scanner breaking into oscillation due to poor power supply voltage regulation. It should become worse as you turn up the volume. That is common with battery powered scanners. If the SDS200 problem increases with volume, I would substitute a different AC adapter. If volume makes no difference, you have a problem with the programming.

T-band has always been 3 MHz.

That is because TV channels are 6 MHz wide.

 

[Algod]

FSDXCON are you on an SDS200?

 

[fxdscon]

FSDXCON are you on an SDS200?

Yes.