seeking options for HF receiver with Voice Squelch and memory scan

Hello group;

Seeking some direction looking for a HF receiver that has decent memory architecture with memory scan and Voice squelch (syllabic) Basically i would like to scan a group of at least 100 HF frequencies and have the scan stop and squelch open on voice traffic.

Any thoughts on what specific receivers do this well?

Thanks for the input

Matt

While there are several portables - and even Software Defined Radios - that have the memory, and SDRs can have a squelch (tho I've never heard of a syllabic squelch, at least on a hobby level SDR, and never on a portable or tabletop), scanning on HF is not like scanning on VHF and higher. In most cases, a noise burst will fool the squelch into opening. In addition, the lower frequencies are more prone to noise issues, so a typical squelch might need a different setting there.

If you are looking into viewing a range of frequencies, tho, a SDR is the way to go. Our SDR wiki has lots of information on this topic - just note that there are 2 pages, listed here...

Software Defined Radios - The RadioReference Wiki

Software Defined Radios Page 2 - The RadioReference Wiki

and we have a separate SDR forum where you can ask questions. Mike

juneau said:

Hello group;

Seeking some direction looking for a HF receiver ,, memory scan and Voice squelch (syllabic) Basically i would like to scan a group of at least 100 HF frequencies and have the scan stop and squelch open on voice traffic.
Matt

Click to expand...

The syllabic squelch requirement narrows the field. The only receiver I had with syllabic rate squelch and 100 memories was a Harris RF-590. It is a rugged, heavy radio, built in the USA to government specs. Mine was used in an embassy.

The RF-590A is a newer version. Be prepared to spend money.

These radios lack some of the amenities of hobby grade receivers, e.g., notch filter, full passband tuning, etc.

You can read more about the RF-590 here: W7KF - Harris RF590 and view the manual here: RF590

Scanning 100 HF frequencies you will probably miss transmissions if you try to scan that many at a time.

The problem with scanning with a voice syllabic squelch is that the receiver must park on a frequency long enough to detect actual syllables. Scan rate who be slow.

Agencies that need to monitor many HF frequencies use banks of receivers. I've seen sites with racks and racks of R390s... Dozens of them.

Not really, the later version Harris PRC-138 HF/VHF manpack has syllabic squelch and scanning and it works very well. I have an earlier model without scan but the syllabic squelch is awesome on the Harris rigs. It is probably way too expensive to use as just an HF receiver.

I also had a Harris RF-590 and a 590A and don't remember the squelch being syllabic type on those but its been awhile since I've used one.
prcguy

zz0468 said:

The problem with scanning with a voice syllabic squelch is that the receiver must park on a frequency long enough to detect actual syllables. Scan rate who be slow.

Agencies that need to monitor many HF frequencies use banks of receivers. I've seen sites with racks and racks of R390s... Dozens of them.

Click to expand...

I am currently using a motorola micom 2rs ( which has a great voice squelch but no scan stop) and a winradio which has a lousy voice squelch or rather very slow. Not sure if the icom receivers such as ic-r75 or similar would be a good route to my goal. I know previous icom radios had a good voice squelch, especially the HF marine radios. Really I would just like to have a radio running in the background scanning a few dozen active hf freq's while I do other things in my shop,, any more input?

I vote for a Micom.

juneau said:

I am currently using a motorola micom 2rs ( which has a great voice squelch but no scan stop) and a winradio which has a lousy voice squelch or rather very slow. Not sure if the icom receivers such as ic-r75 or similar would be a good route to my goal. I know previous icom radios had a good voice squelch, especially the HF marine radios. Really I would just like to have a radio running in the background scanning a few dozen active hf freq's while I do other things in my shop,, any more input?

Click to expand...

I used the squelch from time to time on my R75 when I had it and it worked fine.

There was a setting I had to change though or a relay would always click. If I remember correctly it was to activate a recorder or something, but the setting was there.

juneau said:

I am currently using a motorola micom 2rs ( which has a great voice squelch but no scan stop) and a winradio which has a lousy voice squelch or rather very slow. Not sure if the icom receivers such as ic-r75 or similar would be a good route to my goal. I know previous icom radios had a good voice squelch, especially the HF marine radios. Really I would just like to have a radio running in the background scanning a few dozen active hf freq's while I do other things in my shop,, any more input?

Click to expand...

What do you mean by no scan stop?

You required two different functions on your hypothetical radio - voice operated squelch and scanning.

Voice operated squelch whilst parked on a single frequency is not so hard - detect voice audio energy in the detector output compared to the background noise level and open the squelch gate - maybe with a digital audio store so that you hear the start of the message. Not as simple as a normal VHF scanner that uses the AGC voltage generated by the signal to lift the squelch gate.

Scanning on HF is problematic in that many signals are not sufficiently strong to raise the AGC voltage to stop the scan, even though they may be perfectly audible. Implementing voice operated squelch requires that the signal is sampled for maybe half a second before deciding if it's valid voice audio or just a noise increase - this means that your scanning would be impossibly slow.

Some frequencies in your scanning selection my have high background noise while others have low - some may have some monkey chatter from adjacent channels too, so HF scanning with squelch has always been very hit-and-miss. HF aeronautical radio uses Selcal to alert the pilot that his control station wants to talk to him - if HF squelch was good enough to be used, then Selcal would be unnecessary.

Thanks to all those that have replied! I think I have found a work around to be able to use the Micom for this function. The Micom has a I/O connector with a pin for accessory scan stop. This pin will pause the scan function when sent to ground. I will setup a audio controlled delay-able relay such as;

ST-ACR1 ‐ Line-Level Audio Controlled Relay - 0.5 to 5 s

to the line level audio out of the radio, when the squelch opens the scan will stop for the delay time I set.
I know this will be a slow scan (the micom has a wide range of adjustable rates) but it should work fine if I am just scanning small banks at a time (like Shares or Cothen)

Any imput?

Matt

Also,

from my research the other radio that will work well for this operation is a ICOM M-800. It has the same issues with scanning the micom does, but also has a scan stop input available. I am unsure of scan speeds on this unit. It does have a voice squelch.

Matt

juneau said:

Thanks to all those that have replied! I think I have found a work around to be able to use the Micom for this function. The Micom has a I/O connector with a pin for accessory scan stop. This pin will pause the scan function when sent to ground. I will setup a audio controlled delay-able relay such as;

ST-ACR1 ‐ Line-Level Audio Controlled Relay - 0.5 to 5 s

to the line level audio out of the radio, when the squelch opens the scan will stop for the delay time I set. ...

Any imput?

Matt

Click to expand...

Matt,

I've been looking at the ST-ACR1 device for a slightly different application. FWIW, the Bogen VAR1 Voice Activated Relay is a fancier device which does the same thing but with a bit more flexibility.

Here is a link to the Bogen VAR1 brochure (PDF):

http://www.bogen.com/products/pdfs/specialelectronicspdfs/VAR1m.pdf

I suspect you might be able to hear the relay click in either device. That could be annoying if the relay clicks too loud. (I haven't used either the ST-ACR1 or VAR1.)

Let us know the results of your efforts.

Great, the Bogen looks even better! the unit will be hidden in a different room so the relay noise won't be a issue!

Thanks!

parnass said:

The syllabic squelch requirement narrows the field. The only receiver I had with syllabic rate squelch and 100 memories was a Harris RF-590. It is a rugged, heavy radio, built in the USA to government specs. Mine was used in an embassy.

The RF-590A is a newer version. Be prepared to spend money.

These radios lack some of the amenities of hobby grade receivers, e.g., notch filter, full passband tuning, etc.

Click to expand...

This radio is also known as the R-2368 in military circles, and was a part of my first specialty school. (My first 'C' school, for those familiar with Navy speak.)

I had a lot of fun with these radios, when working shifts at a remote HF receive site, especially when I had a spare RLPA.

One of these radios with a noise elimination speaker would be a great combination.

Sent via Tapatalk

I got it working with the Motorola Micom, thanks Parnass for the tip on the Bogen VAR-1, it works like a champ, I had to have the scan stop function enabled thru firmware, click the link to see my test video. Keep in mind that the noise level is high so it's not perfect copy.

https://m.youtube.com/watch?v=CmIANGH8q6o

juneau said:

I got it working with the Motorola Micom, thanks Parnass for the tip on the Bogen VAR-1, it works like a champ, I had to have the scan stop function enabled thru firmware, click the link to see my test video. Keep in mind that the noise level is high so it's not perfect copy.

https://m.youtube.com/watch?v=CmIANGH8q6o

Click to expand...

Glad you were able to repurpose the Bogen voice activated switch. Enjoyed watching your video.

I bought a Bogen VAR-1 after my last posting and have been experimenting with it.

Why doesn't someone make a voice activated squelch using the PC sound card? Seems it would be straight forward to program it to squelch audio from an audio source if no voice signal is present using the same idea as the hardware units. It would look for certain speech frequencies to switch the audio out to a speaker, provide a delay time so no syllables are missed, and squelch the audio output if no speech is detected. I would do it myself but don't know how to program a sound card. Are there tutorials to program a sound card?

It's been here all the time....

http://www.ebay.com/itm/VOS-Voice-Operated-Squelch-Audio-Muting-Kit-Form

...and also there is a time-proven circuit in the Australian transceiver Codan 6801 and subsequent models.

Download the service manual from here...

http://www.radiomanual.info/schemi/Surplus_Civil/Codan_6801MK2_serv.pdf

The shematic is on the pdf pages 94 and 95 and there is a good description of how it work and the setup procedure in the text. Looks a fairly simple circuit to reproduce although the PC board will be unobtainable - unless you can find a whole radio on an auction site!

I think we've had this discussion before on this forum but when eludes me!