Compander set to off by default.

[8nannyfoe]

From what I can gather the compander is for reducing noise.   The manual states its useful for long distance communications.   What is the benefit of having it off?   Don't we always want less noise short or long range?   Its almost like that should be an automatic built in feature but yet it gives us the option to turn in on in the Wouxon kg1000.

[Woodsman]

I'm assuming the compander is another name for the NB/ANL (noise blanker/automatic noise limiter)? I think the reason is if you have a station that has very little to no noise (not sure if that's even possible) you can attempt to hear further stations with it off. Think of it like squelch.

 

On my CB I always have my ANL on when I am driving or the engine is on. If I have it off, I can hear interference from the alternator. When the engine is off, I turn the switch off because I have less interference (unless power cords are near).

 

Play around with it, see what works and what doesn't work.

[Radioguy7268]

Compander = Compression & Expander. The idea of a Noise Blanker - at  least as I understand how it was implemented in Low Band radios by Motorola - was a secondary receive circuit slightly off-set in frequency, and that would be used to compare desired signal vs. undesired noise (Figuring that most lower frequency "noise" would be wideband in nature, while the desired signal would be on-frequency).

 

In Compandering, Audio is compressed upon transmit, and expanded upon receive. This allows for a potentially better "envelope" of audio response to be compressed into a given amount of bandwidth. However, it requires more manipulation of the audio components of human voice. You give up a bit of audio purity when using Compandering. Better or worse is often up to the ears of the people using the system (and in my experience, how often the people using the system are pressing the outer edges of coverage/range).

 

There's already a ton written about this type of stuff out there on the internet, so the best way I could describe it is to say that if you're only concerned about quality of audio within your own fleet - give it a try & see how it works on your radios and in your system. If you like it, certainly use it for your system.

 

However, most GMRS radio systems and user groups aren't running Compandering, so your radios would sound "odd" sending out compressed audio to another radio that wasn't set to receive (and expand) the compressed audio. 

[mbrun]

If all radios involved in communication used complementary companding circuits it can have the effect of improving the signal to noise ratio of your audio. However, if both sides of the communication chain not using it communications may not sound as good to you or to others.

 

If you have every heard the term ‘Dolby’ or ‘DBX’ with regards to audio recording noise reduction, both of these were variants of ‘companding’ circuitry/algorithms. Both squashed the dynamic range on the input side and expanded it to normal dynamic range on the output side in an attempt to decrease the effect the noise native in the audio recording medium.

 

I would advise not to use it unless the only people you are communicating are equipped with compatible companders and you have little or no need to talk with anyone else.

[8nannyfoe]

Compander = Compression & Expander. The idea of a Noise Blanker - at  least as I understand how it was implemented in Low Band radios by Motorola - was a secondary receive circuit slightly off-set in frequency, and that would be used to compare desired signal vs. undesired noise (Figuring that most lower frequency "noise" would be wideband in nature, while the desired signal would be on-frequency).

 

In Compandering, Audio is compressed upon transmit, and expanded upon receive. This allows for a potentially better "envelope" of audio response to be compressed into a given amount of bandwidth. However, it requires more manipulation of the audio components of human voice. You give up a bit of audio purity when using Compandering. Better or worse is often up to the ears of the people using the system (and in my experience, how often the people using the system are pressing the outer edges of coverage/range).

 

There's already a ton written about this type of stuff out there on the internet, so the best way I could describe it is to say that if you're only concerned about quality of audio within your own fleet - give it a try & see how it works on your radios and in your system. If you like it, certainly use it for your system.

 

However, most GMRS radio systems and user groups aren't running Compandering, so your radios would sound "odd" sending out compressed audio to another radio that wasn't set to receive (and expand) the compressed audio. 

This is a perfect explanation.   Summed it all up!   Thank you.

[8nannyfoe]

If all radios involved in communication used complementary companding circuits it can have the effect of improving the signal to noise ratio of your audio. However, if both sides of the communication chain not using it communications may not sound as good to you or to others.

 

If you have every heard the term ‘Dolby’ or ‘DBX’ with regards to audio recording noise reduction, both of these were variants of ‘companding’ circuitry/algorithms. Both squashed the dynamic range on the input side and expanded it to normal dynamic range on the output side in an attempt to decrease the effect the noise native in the audio recording medium.

 

I would advise not to use it unless the only people you are communicating are equipped with compatible companders and you have little or no need to talk with anyone else.

I searched the keyword "companding" on this forum and it had nothing about the topic.   These two responses are a perfect explanation.   thanks guys!

[NCRick]

I felt I knew about the functionality of the amplification of lower input sounds to a microphone and the compression or the louder sounds all to maximize the modulation density.  I never heard of that needing to be "unwound" on the receiving radio for the benefit to be realized.  I'd love to hear more on this subject as it is a learning opportunity for me.

[berkinet]

I have read that companding can also be used to reduce the impact of a narrowband to wideband conversation.  Though, at the moment I do not recall how it would be applied. Though, I think it may have been as a repeater option on a GR1225,

[Extreme]

I have read that companding can also be used to reduce the impact of a narrowband to wideband conversation.  Though, at the moment I do not recall how it would be applied. Though, I think it may have been as a repeater option on a GR1225,

 

I have a couple Retevis HT and companding is an option in the software.  These radios will not allow wideband so expect less than optimal performance with repeaters that run wideband.  Would selecting companding in the HT improve it?  Maybe off the wall question but there it is..

Edited February 17, 2021 by WRAF233

[OldRadioGuy]

Usually you see Speech Compressors (the TX half of a compander) with SSB where it will actually increase your average TX power.

It's a bit like an AGC but actually a non-linear form of it. 

The idea is too level things out so you can use higher gain without over modulating.

 

With FM the benefit may not be as clear cut because carrier power is fixed.

It will only increase your average modulation... which probably helps some but maybe not a lot.

I never had an FM radio that has it. 

 

It does make you sound a bit nasal or something but with SSB that's not a big deal.

SSB audio is often a little funky anyway.  So nobody notices too much.

 

Vince

[n1das]

I have played around with the companding option in my commercial radios I use on GMRS.  I end up turning the compander off after a while because of the issues it causes.  The companding feature does work as advertised to help clean up the audio SNR.  The companded audio has a "processed" quality to it and I don't mind that.  The problem is it requires ALL radios talking to each other to also be using companding in order to sound right.  It's an all or nothing type deal.  Radios that don't compress their transmitted audio will sound muffled and distorted when heard out of companded radios.  The expander in the receiver expands audio that wasn't compressed originally and blows it apart and sounds like 'expletive'.  The compander is best left disabled when you have a mix of radios that do and don't compand their audio.  Motorola includes a low level expander (LLE) option in their top tier radios.  When using LLE, the transmit audio is not compressed, only the received audio is expanded by a small amount.  It gives the audio a very slightly "fuzzy" quality to it under some conditions.   Overall if a radio has companding capability, the radio needs to include the option to disable the compander.  The compander feature should be OFF by default.

 

The Motorola Talkabout FRS bubble packs use companding.  Motorola calls this feature "X-Pand".  The compander is always enabled and with no option to disable it.  With Motorola's VHF and UHF business radios, the Business Bubble Packs as I like to call them also compand audio on narrow bandwidth channels with no option to disable the compander.  People who have complained about bad receive audio quality out of the Motorola Talkabout FRS bubble packs are really complaining about the effects of the compander on the received audio, especially when hearing radios that don't compress their transmit audio because they don't have companding.  Motorola could greatly improve the Talkabout FRS bubble packs by simply adding the option to disable the compander.

 

My wife (g/f at the time) and I had a pair of Motorola Talkabout 250 FRS bubble packs in the early days of FRS.  The Talkabout 250 was one of the early 14-channel FRS bubble packs from Motorola.  It was one of the first models to push their "X-Pand" audio companding feature.  Motorola added X-Pand to all of their analog radios back then.  Motorola's top tier radios have the ability to enable or disable companding on a per channel basis.  With Motorola's FRS bubble packs and their business bubble packs, the compander is always enabled.  The Talkabout 250 had LOUD audio for hearing them in noisy environments which I liked but the companded audio sounded like 'expletive'.  The radios aggressively companded the audio by over-compressing the transmitted audio and over-expanding the received audio.  The companded audio quality was so bad and to the point that basic functionality of the radio was impaired.  The radio was almost unusable with radios that don't compand their audio.  It was THAT bad.  Reducing the expansion ratio in the expander part of the companding system would have helped a lot.

 

Wikipedia article on companding:

https://en.wikipedia.org/wiki/Companding

[AdmiralCochrane]

Not GMRS, but on ham uhf and vhf, I run Compander on on my Anytone 578 and always get compliments on my transmission quality