Channels that buzz

[WRVG593]

So I have a couple of radios and was wondering why all of them seem to have the same issue. Amongst all of these radios, the same frequencies in my area decide to 'buzz'. I will list the frequencies now.

FRS/GMRS Channel 1- 462.562

FRS/GMRS Channel 13- 467.687

FRS/GMRS Channel 18- 426.625

Yellow Dot - 464.550

Does anyone understand what this could be?

[SteveShannon]

The last two of the frequencies you listed are not GMRS frequencies, but the first two are only 500 Hertz away from the interstitial center frequencies - it may be that your display just doesn’t show the fourth place.  You might be picking up either interference or digital transmissions on those frequencies.  Unfortunately I have heard that there are some low powered devices that have been imported, such as baby monitors, which use those FRS frequencies.

From the regulations:

The GMRS is allotted 30 channels - 16 main channels and 14 interstitial channels. GMRS stations may transmit on any of the channels as indicated below. 

(a)462 MHz main channels.Only mobile, hand-held portable, repeater, base and fixed stations may transmit on these 8 channels. The channel center frequencies are: 462.5500, 462.5750, 462.6000, 462.6250, 462.6500, 462.6750, 462.7000, and 462.7250 MHz. 

(b)462 MHz interstitial channels.Only mobile, hand-held portable and base stations may transmit on these 7 channels. The channel center frequencies are: 462.5625, 462.5875, 462.6125, 462.6375, 462.6625, 462.6875, and 462.7125 MHz. 

(c)467 MHz main channels.Only mobile, hand-held portable, control and fixed stations may transmit on these 8 channels. Mobile, hand-held portable and control stations may transmit on these channels only when communicating through a repeater station or making brief test transmissions in accordance with § 95.319(c). The channel center frequencies are: 467.5500, 467.5750, 467.6000, 467.6250, 467.6500, 467.6750, 467.7000, and 467.7250 MHz. 

(d)467 MHz interstitial channels.Only hand-held portable units may transmit on these 7 channels. The channel center frequencies are: 467.5625, 467.5875, 467.6125, 467.6375, 467.6625, 467.6875, and 467.7125 MHz. 

[WRVG593]

14 minutes ago, Sshannon said:

The last two of the frequencies you listed are not GMRS frequencies, but the first two are only 500 Hertz away from the interstitial center frequencies - it may be that your display just doesn’t show the fourth place.  You might be picking up either interference or digital transmissions on those frequencies.  Unfortunately I have heard that there are some low powered devices that have been imported, such as baby monitors, which use those FRS frequencies.

From the regulations:

The GMRS is allotted 30 channels - 16 main channels and 14 interstitial channels. GMRS stations may transmit on any of the channels as indicated below. 

(a)462 MHz main channels.Only mobile, hand-held portable, repeater, base and fixed stations may transmit on these 8 channels. The channel center frequencies are: 462.5500, 462.5750, 462.6000, 462.6250, 462.6500, 462.6750, 462.7000, and 462.7250 MHz. 

(b)462 MHz interstitial channels.Only mobile, hand-held portable and base stations may transmit on these 7 channels. The channel center frequencies are: 462.5625, 462.5875, 462.6125, 462.6375, 462.6625, 462.6875, and 462.7125 MHz. 

(c)467 MHz main channels.Only mobile, hand-held portable, control and fixed stations may transmit on these 8 channels. Mobile, hand-held portable and control stations may transmit on these channels only when communicating through a repeater station or making brief test transmissions in accordance with § 95.319(c). The channel center frequencies are: 467.5500, 467.5750, 467.6000, 467.6250, 467.6500, 467.6750, 467.7000, and 467.7250 MHz. 

(d)467 MHz interstitial channels.Only hand-held portable units may transmit on these 7 channels. The channel center frequencies are: 467.5625, 467.5875, 467.6125, 467.6375, 467.6625, 467.6875, and 467.7125 MHz. 

I understand that yellow dot is not a gmrs frequency. Only asking for recieving purposes, as my radio receives FRS/GMRS 1-22, all stars and dots, MURS, and extra things such as local police and fire 

[wrci350]

6 hours ago, WRVG593 said:

I understand that yellow dot is not a gmrs frequency. Only asking for recieving purposes, as my radio receives FRS/GMRS 1-22, all stars and dots, MURS, and extra things such as local police and fire 

What you are hearing is a digital transmission, probably DMR.  DMR is not permitted on GMRS, but that doesn't mean someone isn't using it.

[WRVG593]

12 hours ago, wrci350 said:

What you are hearing is a digital transmission, probably DMR.  DMR is not permitted on GMRS, but that doesn't mean someone isn't using it.

It's just weird because it is the same spots at all times, and it's a constant buzz. Not randomly. Like at the end of my street, yellow dot will buzz 24 7.

[wrci350]

Just now, WRVG593 said:

It's just weird because it is the same spots at all times, and it's a constant buzz. Not randomly. Like at the end of my street, yellow dot will buzz 24 7.

Hmmm.  That sounds more like interference.  Are there street lights at the end of your street?  Traffic signals?  Transformers?

[SteveShannon]

If you’re using a receiver that doesn’t filter out “privacy tones” they would sound like buzzing. Does the buzzing sound like it’s at or below 260 Hz?

This thread is why I suggested it could be a monitor device:

https://forums.mygmrs.com/topic/1969-new-interfering-ix-signals-baby-monitors-using-gmrsfrs/?_rid=6309

[WRVG593]

2 hours ago, wrci350 said:

Hmmm.  That sounds more like interference.  Are there street lights at the end of your street?  Traffic signals?  Transformers?

It's possible. The reason I say this is because it happens at the end if the street with a stop light, and right next to a warehouse after I get on the highway

[Sab02r]

Interference near a warehouse is not surprising as there are a myriad of commercial and industrial devices that can produce RFI, particularly in aging buildings.  Variable frequency drives used to run HVAC equipment are a common sources of electrical noise.

http://www.vfds.org/vfd-and-rfi-708163.html

"The conclusion, later confirmed by the VFD manufacturer, was that the building, without a solid earth ground, was acting as an antenna."

[AdmiralCochrane]

On 2/1/2023 at 2:45 PM, Sab02r said:

Interference near a warehouse is not surprising as there are a myriad of commercial and industrial devices that can produce RFI, particularly in aging buildings.  Variable frequency drives used to run HVAC equipment are a common sources of electrical noise.

http://www.vfds.org/vfd-and-rfi-708163.html

"The conclusion, later confirmed by the VFD manufacturer, was that the building, without a solid earth ground, was acting as an antenna."

Since I use my HT's (GMRS and dual band ham) on commercial roofs while I am on break from work and I work on a LOT of equipment with VFD's, I read the article.  I have NEVER heard a VFD making noise on VHF or UHF.  If I read the article correctly the VFD in question was Chinese JUNK AND incorrectly installed. All of the ones I see at work are Korean, Japanese or European.  I have never come across any equipment using the Chinese JUNK in question. 

Despite this solid example, I think you are much more likely to find solar panel controllers making spurious RF than a VFD.  There are numerous examples of solar panel controller manufacturers getting caught distributing crap. 

[WRUU653]

On 2/1/2023 at 11:45 AM, Sab02r said:

The conclusion, later confirmed by the VFD manufacturer, was that the building, without a solid earth ground, was acting as an antenna."

I have to say when I first saw this I thought maybe VFD’s effected UHF and VHF differently and I just wasn’t aware but I have to agree with @AdmiralCochrane on this because I used radio’s around extremely large VFD’s (water treatment, waste water treatment plants) extensively and it was never an issue.  I had forgotten until just this moment there were times we used both UHF and VHF. 

[wrci350]

OK so are you hearing something like this?  Or just static?

 

 

 

[SteveShannon]

Or like this? This is the sound of DMR on analog:

[WRVG593]

14 hours ago, wrci350 said:

OK so are you hearing something like this?  Or just static?

 

 

 

 

13 hours ago, Sshannon said:

Or like this? This is the sound of DMR on analog:

 

69713266866__0F6DB109-652A-4953-9EF0-588F7C4C79E5.MOV 794.05 kB · 0 downloads

That's what happens generally when I'm scanning though VHF and UHF freq, but never on Yellow dot, or FRS Channel 1, 3, and 18. 

[SteveShannon]

3 hours ago, WRVG593 said:

 

That's what happens generally when I'm scanning though VHF and UHF freq, but never on Yellow dot, or FRS Channel 1, 3, and 18. 

Can you record what you’re hearing so we can hear?

[WRVG593]

On 2/4/2023 at 3:43 AM, Sshannon said:

Can you record what you’re hearing so we can hear?

Sure will. Give me probably till tommorrow. Will post soon!

[WRVG593]

On 2/4/2023 at 3:43 AM, Sshannon said:

Can you record what you’re hearing so we can hear?

 

On 2/3/2023 at 9:49 AM, wrci350 said:

OK so are you hearing something like this?  Or just static?

 

 

 

Yellow dot is the only "dot" frequency that does this. Channels 1, 13, and 18 buzz around me

(462.562)(467.700)(462.625)

[KAF6045]

19 minutes ago, WRVG593 said:

 

Yellow dot is the only "dot" frequency that does this. Channels 1, 13, and 18 buzz around me

(462.562)(467.700)(462.625)

Interstitial #1 is 462.5625MHz, Interstitial #13 is 467.6875. Main #18 /is/ 462.6250.

467.7000 is the input frequency for Repeater channel #rp21 (aka #29)

[SteveShannon]

On 2/6/2023 at 1:49 PM, WRVG593 said:

Sure will. Give me probably till tommorrow. Will post soon!

So, those loud buzzing sounds are not CTCSS.  They're way too loud for that.  I don't know what they are.  Does it happen only when you're in your car?  Does it happen when you're in you house?  If you go to the other side of town do you still hear it?  You might have to put a directional antenna on the UV5R to triangulate the source.

[WRVG593]

21 minutes ago, Sshannon said:

So, those loud buzzing sounds are not CTCSS.  They're way too loud for that.  I don't know what they are.  Does it happen only when you're in your car?  Does it happen when you're in you house?  If you go to the other side of town do you still hear it?  You might have to put a directional antenna on the UV5R to triangulate the source.

So it happens outside ny neighborhood, all the way 30 minutes to work on 275 (I live in ohio)

[Sab02r]

On 2/2/2023 at 7:14 PM, AdmiralCochrane said:

Since I use my HT's (GMRS and dual band ham) on commercial roofs while I am on break from work and I work on a LOT of equipment with VFD's, I read the article.  I have NEVER heard a VFD making noise on VHF or UHF.  If I read the article correctly the VFD in question was Chinese JUNK AND incorrectly installed. All of the ones I see at work are Korean, Japanese or European.  I have never come across any equipment using the Chinese JUNK in question. 

Despite this solid example, I think you are much more likely to find solar panel controllers making spurious RF than a VFD.  There are numerous examples of solar panel controller manufacturers getting caught distributing crap. 

No dispute from me.  Solar installations are absolutely a possible source of RFI, and more and more common across the nation.

With regard to VFDs, all VFDs produce some RFI no matter their country of origin.  It is the installation (grounding and shielding) that mitigates emissions.  Electrical contactors and cross-line motor starters with failing components can also produce RFI with no VFD present.

For the OP, since it seems like a fairly widespread area of interference (assuming it happens absent the presense of your vehicle as Sshannon mentioned) it might be worthwhile to take note of any particularly large power transmission lines along your route.  When time allows, follow them as far as they parallel your normal travel pattern on public thoroughfares, and investigate the locations of any large electrical substations where 14400 volts steps down to 4160 (or similar) to feed natural gas compressor stations, mining or foundry operations, or similarly large electrical customers.  

[SteveShannon]

It is classic RFI and if it exists everywhere in the area when you are outside the vehicle and the vehicle is completely turned off (no fancy LED lights - they’re a common source) then it’s probably more than we can diagnose.  That leaves two obvious choices:

Contact a local ham club and ask for help tracking it down, or avoid those frequencies. Personally, I would simply avoid the frequencies.

[AdmiralCochrane]

I just had a thought about the VFD's I see at work ... they are always completely shielded, they are not standing alone on rooftop equipment the way they are in mechanical rooms. In fact, some Carrier brand equipment has some of the electricals inside 3 layers of RF shielding.  Really annoying to take the panels off for testing.  Either something inside is very noisey or very prone to receiving noise.  Manufactures don't put in an extra screw, much less an additional stamped panel if they don't have to. 

Now you guys have me wanting to take an SDR receiver into a mechanical room with stand alone VFD's

[Sab02r]

I suspect you still won't see huge amounts of RFI even on IP20 drives that are modern and sized and installed properly.

Its usually when you see questionable installations, repurposed drives and enclosures, long runs of unshielded cabling without drains, poorly-sized drives, aging motor starters, dirty corrosive environments, or poorly maintained systems that things get fuzzy...but there is no shortage of those places.

I have a customer that runs two 600hp and two 800hp electrically driven compressors built in the '60s (which are soon to be replaced by turbines).  They produce some serious electrical noise.  Fortunately for them, they have very, very few neighbors to complain.

[SteveShannon]

On 2/7/2023 at 4:56 PM, WRVG593 said:

So it happens outside ny neighborhood, all the way 30 minutes to work on 275 (I live in ohio)

Have you found anyplace(s) where it doesn't happen?