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Author Topic: Simple Squelch for ARC-5?  (Read 23440 times)
KB7NRN
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Posts: 22




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« on: August 13, 2008, 02:12:06 PM »

I'm looking for a schematic or article for a simple squelch circuit for the ARC-5 Command Set receivers. It used a 1N34 diode, pot and a few other parts. It was in one of the Ham mags from the late '50s or '60s.

Any help would be appreciated.

Thanks,
John
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W8ZNX
Member

Posts: 1




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« Reply #1 on: August 14, 2008, 01:36:50 AM »

pray tell
why

want a squelch
many new age
plastic rice box rigs have a squelch

please
don't do this
to a 60 plus year old tube radio
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KB7NRN
Member

Posts: 22




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« Reply #2 on: August 14, 2008, 09:13:32 AM »

Well, if you must know Craig, I have a super regen VHF receiver I built and would like to add squelch to it.

I was told that there was this mod to the ARC-5 and I would like to duplicate it if possible.

If I did decide to add a squelch to a 60 year old radio, I guess it would be my call now wouldn't it.

So if you know of such a circuit I'd like to see it, if not please abstain from posting in this thread.

Thanks,
John
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KA5N
Member

Posts: 4380




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« Reply #3 on: August 14, 2008, 12:16:10 PM »

I don't think that a squelch circuit designed for a superhetrodyne receiver would be readily adaptable for a super regen.  A squelch circuit for a superhet receiever usually works from the AGC circuit (or works ON the AGC circuit)to reduce gain or mute the audio. A super regen uses feedback to increase gain and has no AGC as such.  You change the feedback to change the gain.
Also just because a circuit doesn't have many parts doesn't mean that it will work well or be suitable in a different circuit.
So the ARC-5 part of the request is just coincidential?  Before you tell me to get lost too, I just want to say that you can do whatever you want to including hanging a cow bell on your super regen if you like.
Allen
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W3LK
Member

Posts: 5639




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« Reply #4 on: August 14, 2008, 01:57:22 PM »

Who uses squelch on HF? No one I know.

73,

Lon - W3LK
Naugatuck, Connecticut
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KB7NRN
Member

Posts: 22




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« Reply #5 on: August 14, 2008, 08:01:46 PM »

Sigh....

I was looking for the article on the ARC-5 squelch mod because another ham who had used it in the past thought it might be of use. I just wanted to see if it could be adapted to my VHF super regen.

My first post asked if any one had seen the article or knew of the circuit and any HELP alnog these lines would be appreciated. It just seems on these discussion groups every swinging Dick ham know-it-all has to add his 2c to prove how smart he is rather then stick to the spacific request and be helpful. I really don't care about your opinion otherwise and really hate wasting my time to even write this.

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W8ZNX
Member

Posts: 1




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« Reply #6 on: August 15, 2008, 01:55:53 AM »

Alas, what ignorant sin have I commited?
Shakespeare,
O 4.2.70

might have gotten better answers

if were not like a magician

having us think
you were looking for a squelch circuit
for a 60 plus year old mil surplus hf superhet receiver

not a  rush box vhf receiver

we are to abstain form posting in this thread

telling others to shut up
is not going to help you

so some research
look for audio derived squelch circuits

skip anything using the avc line
as posted by others
you got no avc to hang a squelch circuit on to

many modern a go go
FM squelch circuits are audio derived
between the first and second audio stages
starting with a high pass filter

don't remember
..................ever
seeing squelch
on a rush box
National vhf rush box's
Heathkit Lunch Box rigs did not have a squelch

try Yahoo user group regen
when you do
ask your real question

want straight answers
ask the right question

don't lead us to believe
something else

dit dit

Mac
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W3LK
Member

Posts: 5639




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« Reply #7 on: August 15, 2008, 07:11:01 AM »

<<  It just seems on these discussion groups every swinging Dick ham know-it-all has to add his 2c to prove how smart he is rather then stick to the spacific request and be helpful. I really don't care about your opinion otherwise and really hate wasting my time to even write this. >>

And attitudes like this will get you fewer responses in the future. I know I'll not bother replying in the future, so that should make you happy.

73,

Lon - W3LK
Naugatuck, Connecticut
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N2EY
Member

Posts: 5079




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« Reply #8 on: August 15, 2008, 07:19:40 AM »

You can't put squelch on a superregen. Here's why:

Squelch works by detecting the difference between when there's a signal and when there isn't. In superhets this is usually done by looking at the AGC voltage, and deciding that if it's above a certain point, there's a signal, and if it's below a certain point, there isn't. The squelch control determines the threshold point. This is how the ARC-5 squelch mod worked.

On FM receivers it's often done by looking at some voltage in a limiter stage.

But your superregen has neither AGC nor a limiter stage. Worse, it is a characteristic of superregens that they hiss like mad in the absence of a signal.

These characteristics are two reasons why superregens fell out of use (the others are detector radiation unless you add shielding and an RF stage, and lack of selectivity/stability compared to superhets).

A common jargon name for a superregen is "rushbox" because of all the hiss. If there were a practical, simple squelch for a superregen, you can bet it would be well-known among hams.

--

If you want to do boatanchor VHF, your next step might be to get a BC-455 (6-9 Mc. ARC-5 receiver) and use it as a tunable IF for an external 6 or 2 meter converter. The BC-455 could be modified to have squelch, noise limiter, etc.

73 de Jim, N2EY

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WB6BYU
Member

Posts: 18457




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« Reply #9 on: August 15, 2008, 02:06:09 PM »

Although it probably won't work in an ARC-5, I probably
have a circuit for a squelch circuit for a super-regenerative
receiver around somewhere in a copy of Amateur Radio
Techniques or Technical Topics Scrapbook (both published
by the RSGB based on the Technical Topics column in their
journal that G3VA has been editing for the last 50 years
or so.)

It probably uses transistors, but you should be able to
adapt it for glowFETs.
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AA4PB
Member

Posts: 15042




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« Reply #10 on: August 15, 2008, 05:52:05 PM »

On most FM receivers squelch is done by detecting the noise. The higher the noise level, the tighter the squelch. When a signal comes on, the noise level decreases and the squelch opens to let the audio through. Something like this just might work with a superregen receiver. Tap off at an early audio stage, run through a high pass filter to remove the low frequency voice audio, leaving only the high frequency noise. Rectify and filter the noise audio into a voltage level that controls a later audio stage (off with noise, on with no noise).

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Bob  AA4PB
Garrisonville, VA
K3HVG
Member

Posts: 149




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« Reply #11 on: August 18, 2008, 01:44:51 PM »

You may find an audio squelch circuit that was used with the Heath Twoer and Sixer.  It was a bridge circuit that sort of nulled out the background noise until a signal came through.  Crude but quasi-effective.  Check with the Heath bunch for the info...perhaps.
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K6ZL
Member

Posts: 34




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« Reply #12 on: April 12, 2010, 10:45:37 PM »

Well, you can put a squelch on a super.  It uses a couple of lamps and is only about 90 % effective but I'll take that 90%.  If I run across it. I'll post it here.     NOW, I'm looking for a really cool squelch circuit for a 3-6 mhz Command set.  Please send url, if you know of one.  Thanks, Ron.
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G3RZP
Member

Posts: 1265




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« Reply #13 on: April 13, 2010, 02:21:22 AM »

Totally confused because there were two things called an ARC-5. One was a VHF receiver and that did have squelch, using a pair of 12SL7s.

There was an article in Break-In, the journal of the New Zealand Amateur Radio Transmitters Society in November 1978 by Nat Bradley, ZL3VN, who is still listed on the eHam call search. The article was called  'Taming the superregenerative detector', and was on pages 410 to 415. He used an FET in a Hartley, with tuned circuit between drain and base, and a regen control in the source. He found a 25mV increase in source voltage when a signal was received, which could be DC amplified to actuate a squelch. You might find it worthwhile dropping him a line.

Possibly a similar circuit using a triode as the detector and controlling the amount of regeneration by a variable cathode resistor might work.

It seems that a seperate quenching circuit provides better and more stable results, incidentally.

There was a book published in 1950 by Cambridge University Press, written by Dr. J. R. Whitehead, entitled 'Super-regenerative receivers'. It isn't available on Abe books, but you might be able to get a copy from a library. Apparently, it's pretty heavy on the theory, but it's based on a lot of the wartime work done on making stable super-regens for applications such as IFF etc.

Hope this is of some help.

73

Peter G3RZP
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N2EY
Member

Posts: 5079




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« Reply #14 on: April 13, 2010, 09:08:17 AM »

I'm looking for a really cool squelch circuit for a 3-6 mhz Command set.

I don't know if there's a squelch circuit in the manuals and articles listed below. But if you're interested in "Command Sets", the resources there are a must-have.

http://www.mines.uidaho.edu/~glowbugs/arc5pages.htm

has the book "Command Sets", the original military manual on them, and lots more info/mods/conversions.


http://www.mines.uidaho.edu/~glowbugs/SurpConv.html

has the 3 volume set of Surplus Conversion Manuals, which include some ARC-5 stuff.

All free for the download.

73 de Jim, N2EY

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