Ground Loop Isolators

Has anyone tried these on their feeds before?

Ive been battling endless hours trying to eliminate the "white noise" on my feed without sacrificing volume but I am fighting a losing battle.

Can someone open up my feed, have a listen and tell me if adding ground loop isolators in the middle will do any good?

Thanks!

Pictou County Public Safety

They don’t work too well but what does work is having the usb connected to a computer that is not carrying your audio

Moved.

This has completely eliminated all white noise on my feed.
https://www.amazon.com/gp/product/B019393MV2/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

Res21cue said:

Has anyone tried these on their feeds before?

Ive been battling endless hours trying to eliminate the "white noise" on my feed without sacrificing volume but I am fighting a losing battle.

Can someone open up my feed, have a listen and tell me if adding ground loop isolators in the middle will do any good?

Thanks!

Click to expand...

I listened but it really sounded pretty good on the P25 side, apart from the occasional "wobbly" sounds one gets from a scanner on P25.

However, if you have a ground loop issue you can usually identify it by the noticeable hum. There are nice isolators on eBay for decent prices; I bought a three-pack of the ones in the link for $17 including shipping, cleared up all my ground loop issues.

REIIE Ground Loop Noise Isolator for Bluetooth Car Kit Audio System/Home 2Pack

Res21cue said:

Has anyone tried these on their feeds before?

Ive been battling endless hours trying to eliminate the "white noise" on my feed without sacrificing volume but I am fighting a losing battle.

Can someone open up my feed, have a listen and tell me if adding ground loop isolators in the middle will do any good?

Thanks!

Pictou County Public Safety

Click to expand...

I hear the hiss. Ground Loop Eliminators won't eliminate it. If using the Mic input, turn it down a bit and turn up the scanner volume a bit.

I know that it sounds a little crazy, but has anyone tried bluetooth for transmitting audio from the radio to the streaming device? With no direct connection, does the ground loop issue go away? BT transmitters with 3.5 mm plug are available for $10-15. The RPi3 and piZero W both have integrated BT. I set one up tonight and BT'd audio to it from my iPad with no problem. The piZero ($10) would make a very compact little streamer set up this way.

DC31 said:

I know that it sounds a little crazy, but has anyone tried bluetooth for transmitting audio from the radio to the streaming device? With no direct connection, does the ground loop issue go away? BT transmitters with 3.5 mm plug are available for $10-15. The RPi3 and piZero W both have integrated BT. I set one up tonight and BT'd audio to it from my iPad with no problem. The piZero ($10) would make a very compact little streamer set up this way.

Click to expand...

Excellent suggestion. BT is also a solution to avoid tickets with driving and cell phone in CA now.
One thing I'm curious about, does that include licensed ham operators? Are they subject to these new cell phone use laws in California and other states?
In California it is illegal to be holding or even touching a cell phone while driving. Bluetooth resolves those limitations to some level.
Does anyone know if this law also applies to ham radio operators with mobile or portable radios?

This new law in California to make it illegal to touch a cell phone while driving was a result of a new phenomena that started with streaming video and facebook's rise to fame with social media and distracting drivers resulting in tragic accidents mostly teens. It is a motivation to get a ham radio license as most likely the limitation is not extended to that group.

One follow up comment, Apparently Broadcastify feeders are required to transmit a continuous stream. In my case, rtl_fm does that by padding bytes that are not audible.

IMHO this is a major flaw and uses too much bandwidth. The Broadcastify server coders could fix this problem by changing the connect status timeout parameters.]
My suggestion is to kick the constant stream requirement to a 60 second strobe watchdog pulse.

BTW, these are my feeds again. Very good audio compared to most feeds and squelch works well.
No background humm needed to keep the feed alive which seems to be the case with other feeds.
https://www.broadcastify.com/listen/feed/23831
https://www.broadcastify.com/listen/feed/25781

The major cause of the hiss your hearing is that it is coming from the scanner. The audio is not being muted all the way in the scanner and the low level static or hiss is being let through the squelch system and out to the speaker or the audio accessory jack.

You could build a high pass filter to knock off the highs in the audio stream. This would help to lower the hiss your hearing.

A ground loop elimination device is not much more than a transformer coupling the audio in to the audio out. This breaks any hard ground connection in the audio path. This may work to reduce or eliminate a hum caused by the ground connection between two devices. Anything beyond that, the ground loop eliminator will do nothing for.

JACK26 said:

One follow up comment, Apparently Broadcastify feeders are required to transmit a continuous stream. In my case, rtl_fm does that by padding bytes that are not audible.

IMHO this is a major flaw and uses too much bandwidth. The Broadcastify server coders could fix this problem by changing the connect status timeout parameters.]

Click to expand...

I'm not sure what you are talking about. It doesn't make sense to me.

What I know is Broadcastify uses Icecast servers which are built on the Shoutcast protocol. I believe Lindsay said several years ago that they have a custom version. Media Players also needs to implements the Shoutcast protocol to work. A constant stream is required, that is the way the Shoutcast protocol works.

Are you sure rtl_fm is padding bytes when not audible. What is defined as "not audible"? A certain threshold level or -96db total quiet? I thought padding bytes was done at the mp3 encoding level to maintain a constant average bitrate.

My suggestion is to kick the constant stream requirement to a 60 second strobe watchdog pulse.

Click to expand...

What software has that option and what would that do?

No background humm needed to keep the feed alive which seems to be the case with other feeds.

Click to expand...

Any feed that has a background hum can be eliminated and the feed will keep on going.