Voice Activated Squelch

 

From time to time I use to set the dial of my HF radio to some frequencies where voice QSO’s are expected - like local nets or WWF/SOTA/POTA.

The noise is annoying for me and my family. One solution is to keep the volume very low but this means I miss the calls when I am not near the radio.

Another one is to use the “classic” Squelch circuit that almost any radio with FM mode had it but this works awkward in HF, passing any signal above a certain energy level, including QRM/QRN.

 

I have had a Codan radio and I remember a nice (and rare) feature it had, a Voice Squelch which let pass the voice and muted other QRM/QRN.

Wouldn’t be nice to have the same function on my IC-7100???

This is why I made VAS-V4, described here.

Adrian 

Last post on Blogger - Moving to Substack

 

Well...

There are some years from my first blog post and Blogger was good untill it became too complicated to post photos and videos.

Being a brave ham, I decided to move my public activities on Substack.

Yes, I know, I do have almost 1 mil. views, for which I THANK YOU, my followers.

I will import there the posts from here and I hope this will work fine.

I will still post here from time to time links to some of the Substack post I will publish to update the followers and use the search engines indexing of this platform. 

See ya on the other... platform!

Cheers, 73

Adrian YO3HJV

Lab599 TX-500MP

Finally, finally, she/he/it arrived while I am still in Wien (OE1)!

It was a little adventure but now I am in the select circle of Lab599 TX-500 MP owners!

I have it for just a few days but, man, oh, what a nice radio is here!

And with a spare BP-550 battery pack.

 

Xiegu G90 squawk at high volume

 On the G90 Groups is an interesting discussion about an audio feedback (squawk) at high volume.

The subject is now locked but I think it will be a good added value to point to the source and the solution.

As I wrote there,  the problem is most probably due to the MLCC capturing audio and producing a feedback via the PCB.

It is a known phenomenon that cheap MLCC act like condenser microphones.

Today, I opened for the last time my G90 to put back the LDOs as the small SMPS put some spurious into 20m band and this radio will be put on sold.

I did some photos on the front end bandpass filters (see this post) for future reference and I get back to a small soft plastic cylinder placed on the shield above the filters.

I did noticed it a while ago and  I didn't payed attention until now with that discussion in my "rear memory".

Yup, this is precisely what I reccomended to reduce that squeal, a simple damper to reduce the vibration between the upper case that hold the speaker...

It will be interesting to check if those radios that exhibit the audio feedback have that little plastic damper. 

If not, I think it would be easy to add something similar or a little piece of foam. 

 

Baofeng DM-32 Desktop Charger YPT-C21A

 Baofeng DM-32 desktop "charger" isn't a proper charger but a desktop stand with a charging indicator.

The charging circuit is built into the battery and powered by a 5V/1A power supply.

Inside the desktop stand is a detection circuit that change the colour of a dual-colour LED based on a LM358 dual op-amp configured as a comparator.

Here is the schematic: