hpr-knowledge-base/hpr_transcripts/hpr2678.txt

Episode: 2678
Title: HPR2678: Explaining the controls on my Amateur HF Radio Part 4
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr2678/hpr2678.mp3
Transcribed: 2025-10-19 07:22:53

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This is HPR Episode 2678 entitled, explaining the controls on my amateur HF Radio Part 4 and in part on the series, HAM Radio, QSK.
It is hosted by MrX and in about 16 minutes long and carrying an explicit flag.
The summary is, in this episode I cover the first four receiver section controls on the DS940.
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Hello and welcome Hacker Public Radio audience. My name is MrX and welcome to this podcast.
As usual, I'd like to start by thanking the people at HPR for making this service available to us all.
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I mean, I'm sure you must have something interesting to say.
Okay, so this is the next part in my series of the controls of my amateur radio came with TS940S.
It covers, I thought that this would be the last section, but they would cover the receiver section of the radio.
But as the receiving is the main function of the actual unit, it was a bit more complicated than I expected.
And it was getting a bit long, so I split it into two.
So there's one more final part after this, so there should be five parts in total.
At least this one isn't too long, though it isn't rather waffly, so hopefully you won't all fall asleep.
Anyway, sit back and enjoy.
So now onto the final section, they receive section of the radio.
And the first row, the first knob on the top row has a dual function, it's got an outer ring and an inner ring.
And the outer ring, you may be familiar with, is for Squelch, SQL.
And it actually, if you've got a strong enough signal, bizarrely, I didn't think you could use Squelch on sideband stations, but you can.
And it doesn't actually work, again, clever circuitry.
I'll see if I can find a station and get it to operate.
Let's see if I just turn it.
Who is a volume?
I lost a volume.
Maybe with a volume, yes.
So if you can find a station.
So it's German.
So if I turn the Squelch on.
Now, that's just turning volume to retouch.
That's a Squelch fully up.
And what it does is it has a very slow, when you're on sideband, it has a very slow activation.
So it's only the signal drops for a number of seconds that the Squelch then cuts in and silences things.
But it doesn't, once the signal gets weak, it does just turn to struggle a little bit.
Now, I can simulate that, I think, if I knock in a bit of attenuation, let's just see.
There you go.
So there's actually so much noise in the band that it's still cutting it out.
There you go, that's it, gone quiet.
Open the Squelch again.
So it's not terribly useful on them, on sideband.
And I don't use it at the general speaking.
But if you use it, it is useful on EM or FM now.
So if I give you an example of going to FM, you get this noise all the time.
And if I turn the Squelch up, there you go.
Open.
Close.
So that's like on CB or something that you turn the Squelch up.
And it stops the noise coming through all the time.
So that's Squelch.
And for FM and EM, but fairly useless on sideband.
You can use it.
You can, on a song signal, you can use it.
I have used it in the past.
Let's turn that off.
And turn the Squelch down.
So the next, the inner control is called, is for notch.
And I'm not sure how much I can.
I'm going to carry on with this because I was getting quite long this,
this episode.
But then notch allows you to notch out a tone.
If you, let's say you're talking to a station in a Morse code station,
came in underneath and it would be quite annoying or even just a single tone,
you get tones coming up.
If somebody transmits keys up, you get a carrier, a tone, a hustle.
And you can take that out with a notch filter.
So I'll see if I can find a Morse code station.
And I'll try it, not, not, not, notching it out.
Let's see if I can find one now.
Let's see.
Now, better still.
Okay.
Oh no, the tone's gone.
There's a tone near, for example.
So let's see if I can notch out.
Well, that's probably something tuning the radio actually, tuning it up.
So I'll put the notch filter in and listen for his tone.
Oh, he stopped.
Typical.
Hmm.
All right.
Just take it out.
A tone that I can try and get it over.
There's a tone and Morse code.
Now, try and notch that out.
So.
There you go.
Actually, out.
That's a third.
That's it.
That's it off.
Okay.
That's a notch in now.
I'm going to hardly hear the tone back on again.
Off.
There you go.
So basically, well, that does it.
It's a very narrow, a very narrow audio filter, which you can tune.
So you can shift it up and down the audio spectrum.
So let's see.
You tune it so that at 1000, 1000 hertz.
So at 1000, at one kilo here, I should say, at one kilo here, it'll maybe 1000.
Maybe it's 100 hertz wide.
So at 1000 and 50 and 950 hertz, that's worth of 100 hertz.
Anything in that, anything between 950 and 1000 and 50 gets reduced to an amplitude and notches it out.
But you can adjust the frequency of that notch up and down so that you can take out a single tone.
Of course, if the tone changes to another frequency, or if you've got two tones, then you're stuffed.
With modern amateur equipment, these notch filters can follow a moving tone.
Do clever things like that and clever digital signal processing and whatnot.
So I think I've moved on since I said earlier, where you could do these things manually, with a manual notch.
Just do that again, something like that one.
Yeah, another station.
And it stopped.
No, this is just coming.
So that's off, loud, quiet.
Yeah, so it's not perfect, but...
So we're here all day.
That's an notch filter.
Quite useful, aren't actually.
So next control along the top panel, we've got pitch and AF tune.
And that's to do with adjusting the pitch and tone of our CW station.
I haven't used that very much because I don't do CW.
I can't do CW as I said before.
I know about 80% of the alphabet.
So that's not terribly good.
You did to tell the person to say sorry.
Sorry, I don't have a conversation because I don't know that letter you just sent.
Right.
Let's get a few long winded, isn't it?
Right, next row down from those two knob, the top knobs on the right hand side.
Okay, there's one, two, three, four, five, five latching buttons.
RIT.
Receive.
I'm trying to find the button.
Where is it?
RIT.
Oh yes.
So RIT.
Receive.
I T internal tune.
I should know what that stands for.
But you know, basically normally when you're operating the radio,
if you're sitting on a frequency, say you're sitting on a 7.1 megahertz and you're talking to a station.
Another station comes in.
But now he's a wee bit off and he sounds a bit too high or a wee bit too low.
You've got to tune the big main tuning knob so that you can hear him properly.
But if you do that, then you'll move your transmitter.
And in the station, you're talking, then that'll upset the other station you're talking to,
who's listening to you because it expects you to stay on the frequency you were talking on.
So even a minor change quite dramatically changes the audio.
So I've got an example of that.
So if I go...
Let me see.
Let's see.
Never find a station where you want it.
So there you go.
So that doesn't sound like this, is it?
So there you go.
So that doesn't sound like this, is it?
So it's like Pinky and Perky.
So if you were to adjust your frequency, then that's how you would sound to the other station.
If you were trying to tune your radio to listen to the second person you called in.
So you don't want to adjust your transmit frequency at all.
So doing, pushing the RIT button in, it allows you to tune your...
Change the frequency if you receive it slightly without touching, without affecting the transmitter.
So if you push the RIT button in, then you got a beep.
And RIT appears on the main display.
And when you turn the...
There's a knob below the RIT and it's got RIT slash XIT and it's got a plus and minus on it.
And if you turn it, then it changes the frequency of the receiver but it will not touch the transmitter.
And in fact, what happens is the main display, also the frequency changes.
And next to that, there's two wee digits and they go up to tell you how many kilohertz you've shifted.
So I'm currently five kilohertz above where I was sitting before but the transmitter will not have moved.
So I can twirl at my heart's content and it doesn't affect where I'm transmitting.
And what I can do is I found...
So there's three of us having this conversation, me, Jimmy and Shuggy.
And if Shuggy calls in, I can stab that RIT button, tune him in, listen to him.
And then when Jimmy talks, stab that button and it jumps back to where I was before.
So I can hear Jimmy OK.
And likewise, when Shuggy talks, I push that button and it flips back to the other frequency so I can hear Shuggy.
And flip that button back forward all day and never touch my transmitter frequency.
So it's very, very useful.
You can do something with a transmitter but you would never want to adjust your transmitter frequency so I've never used that button.
And I think we'll close it at that and carry on.
It's getting quite long recording. That's enough for now.
OK, so I hope you enjoyed this podcast. I'll leave it at that.
I think I've got anything else to say. I hope I've bored you too much.
If you want to contact me, I can be contacted at MrX at hpr at googlemail.com.
That's MRX ATHPR, the at symbol googlemail.com.
So until next time, thank you and goodbye.
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