Syllabic Squelch?

[K6GBW]

Just curious, am I the only one that wishes manufacturers would start including syllabic squelch? I like listening to 80 and 40 meters, sometimes for hours on end. Even using the RF Gain to reduce the noise to a pleasant hiss still leave that white noise that slowly lulls me to sleep. I've fallen asleep in the chair by the radio at least a dozen times that past year. I sometimes run squelch on 80 meters because the signals are so strong. But if we had a KenYaCom with syllabic squelch it would be much more pleasant. Syllabic squelch as been around for a long time now. It's not new technology. I'm wondering why its not included on newer radios, unless you pony up for a Codan or Harris.

 

[vagrant]

My Icom R30 receiver has a limited VSC which means it does not have syllabic squelch for SSB. The Icom R8600 and 7100 do offer syllabic squelch.

I'm hoping the upgrade for the 7100 is a 705-ish control head, with the other fun features the 705 has...and it will have syllabic squelch.

 

[majoco]

I have the Codan schematic and printed circuit layout but it's a double sided board and I don't have the equipment to make one. It's a relatively simple circuit with only three quad IC's and quite a few ordinary components. An enterprising kitset manufacturer should be able to produce the board given due regard to copyright or similar.




It works by splitting the incoming audio into two frequency bands, one centred about 850Hz and the other 2.7kHz. If the audio is just noise in both channels, then a comparator sees the same energy in both channels and a FET audio switch is opened and the output is blocked. However voice frequencies will have much more energy in the 850Hz band than the 2.7kHz, the comparator is unbalanced and the FET is closed passing the audio on the the amplifier.

 

[AK9R]

It's a relatively simple circuit with only three quad IC's...

For those squinting at that schematic, it seems that the ICs are LM3900s which is a quad op-amp. 56 cents each from Mouser as a through-hole DIP.

Here's a link to an old thread where this circuit was discussed.

HF radios with working squelch

Does anyone know if it's only the Alinco R83E and Icom radio HF sets that has working squelch ? or if any portable HF sets have working squelch? Has devastated my loop antenna is knakererd for the time being because the interface isn't working!.

forums.radioreference.com

 

[ai8o]

<snip>
I like listening to 80 and 40 meters, sometimes for hours on end.
Even using the RF Gain to reduce the noise to a pleasant hiss still leave that white noise that slowly lulls me to sleep.
I've fallen asleep in the chair by the radio at least a dozen times that past year.
<SNIP>

You are getting older.
Just like me!
Perhaps, its not the white noise that lulls you to sleeeep.
Us oldsters, just can't stay up all night like we used to.

Just ask your wife to come in, and turn the radio off when you are snoring, and don't sound like you are going to be talking anymore.

73
Dan
AI8O
Right here on the edge of dreamland.
zzzzzzzz!

 

[K6GBW]

You are getting older.
Just like me!
Perhaps, its not the white noise that lulls you to sleeeep.
Us oldsters, just can't stay up all night like we used to.

Just ask your wife to come in, and turn the radio off when you are snoring, and don't sound like you are going to be talking anymore.

73
Dan
AI8O
Right here on the edge of dreamland.
zzzzzzzz!

All night? This is at 1 o'clock in the afternoon!

I'm just surprised that, with few exceptions, this feature hasn't made its way into a modern ham transceiver. I've used it on a Codan and it was AMAZING. I know the DX crowd probably wouldn't use it. But I'm betting there are a lot of people that would love it.

 

[prcguy]

Once you've used a good syllabic squelch its hard to use any other kind. It spoils you and I wish every HF radio had it. I still have one Harris RF-5000 series with it and its a dream to use. I don't know what happened to the syllabic squelch kit I built but I don't have any old radios these days to use it with anyway.

 

[ShawnInPaso]

Once you've used a good syllabic squelch its hard to use any other kind. It spoils you and I wish every HF radio had it. I still have one Harris RF-5000 series with it and its a dream to use. I don't know what happened to the syllabic squelch kit I built but I don't have any old radios these days to use it with anyway.

I've never heard of syllabic squelch before, so I googled it. The first article shown states the coast guard uses it, which makes good sense. I was a bit surprised to see this " The purpose of the SRSS is not to suppress noise, it is to recognize that voice is present in the noise, then open the audio path to the radio receiver–even when the amplitude of the signal (voice)-in-noise is only 10dB greater than the noise. "

10db above the noise seem like quite a bit given the description?

 

[prcguy]

It works at much lower SNR levels in the radios I've used. There can be distant lightning static crashes and my syllabic squelch will not open but when a weak voice is there it opens and lets it through then after about a second after they stop transmitting it just goes quiet again like magic.

I've never heard of syllabic squelch before, so I googled it. The first article shown states the coast guard uses it, which makes good sense. I was a bit surprised to see this " The purpose of the SRSS is not to suppress noise, it is to recognize that voice is present in the noise, then open the audio path to the radio receiver–even when the amplitude of the signal (voice)-in-noise is only 10dB greater than the noise. "

10db above the noise seem like quite a bit given the description?

 

[K6GBW]

I got to use a Codan with syllabic squelch and it was a completely different experience from listening to the constant atmospheric noise. From what I understand the circuit isn't complicated and yet it still hasn't made it to ham radios. Just seems odd since manufacturers are always looking for the next cool thing to attract buyers. I think the syllabic squelch would be really popular with 80 and 40 meter rag chewers that like to sit on a frequency for long periods of time. Once you get into the upper bands the noise isn't so bad, but 80 in my neighborhood can get on your nerves. I usually crank down the RF gain to try and reduce it as much as possible. On my Icom IC-7300 I've even used the regular squelch at times to quite the radio between transmissions since the guys on 80 are usually well over S9 anyway.

 

[mancow]

The Codan 2110 I have and micom both have it. It's truly magnitudes of improvement of listening experience. Both work well enough that it's not unlike listening to FM.

I've been contemplating ways to do this for other units using a microcontroller or DSP. I've used some frequency counting libraries with the teensy boards for ctcss detection and it seemed to work well. I'm wondering if a guy could sample the audio and define the two main frequency areas already mentioned then setup a logic comparator in the code to trip an I/O to control the gate.

 

[vagrant]

A friend has a Codan and it is very nice. My 897D when used side-by-side is the ugly one on the double date.

I need to look into this.

 

[WX5812]

I have an icom m710 marine hf and it has a great type sql in it. I would like to build some for my other hf radios in the future.

 

[RFI-EMI-GUY]

This company Naval Electronics, Inc. in Tampa used to advertise quite a bit. It does appear they have a product. While it is pricey, you might be able to use one with an audio mixer if you have several receivers.

VOS-1 VOICE OPERATED SQUELCH for SSB Single Sideband Radio from Naval Electronics

 

[K6GBW]

Hello? KenComSu? Are you listening? We want syllabic squelch!

 

[vagrant]

...until then we suffer with adjusting RF gain