[arm-allstar] hum on my allstar nodes

Joe kc7joe at gmail.com
Mon Apr 27 00:06:26 EDT 2020 

Fix hum on clearnode. Moved node room away from electronics. Also replaced
antenna with TYT MD2017 antenna. Antenna alone fixed most of hum issue


On Sun, Apr 26, 2020, 7:42 PM <arm-allstar-request at hamvoip.org> wrote:

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> Today's Topics:
>
>    1. Re: hum on my allstar nodes (David McGough)
>    2. Re: hum on my allstar nodes (Doug Crompton)
>    3. Re: hum on my allstar nodes (Michael Fleetwood)
>    4. Re: ARM-allstar Digest, Vol 71, Issue 59 (Chris Smart)
>    5. Re: hum on my allstar nodes (Doug Crompton)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 26 Apr 2020 18:12:22 -0400 (EDT)
> From: David McGough <kb4fxc at inttek.net>
> To: "\"Michael Fleetwood via ARM-allstar\"" <arm-allstar at hamvoip.org>
> Subject: Re: [arm-allstar] hum on my allstar nodes
> Message-ID:
>         <Pine.LNX.4.44.2004261808250.30552-100000 at goliath.inttek.net>
> Content-Type: TEXT/PLAIN; charset=US-ASCII
>
>
> Mike,
>
> With radio-less nodes, the biggest issue I've had is noise of the power
> for the mic element. This gives just like you're describing: everything
> from hissing sounds to various hash/hum noises.
>
> How are you powering your mic circuit?
>
>
> 73, David KB4FXC
>
> On Mon, 27 Apr 2020, "Michael Fleetwood via ARM-allstar" wrote:
>
> > I am having a problem with a background hash others hear when I
> > transmit using a radioless node with a Pi3A+ an Alinco EMS57 mic,
> > modified sound fob and audio amp. Received audio is perfect, but when
> > I listen to myself on the parrot the noise sounds a bit like an FM
> > signal that is not fully quieting. I have tried optimising grounding
> > and using different power supplies including a 12v battery and 7805
> > regulator, but the problem persists.
> >
> > Mike
> > VK2AMF
> >
> >
> > At 05:23 AM 27/04/2020, you wrote:
> > >The "RF" hum is caused by some odd phasing relationship and/or RF
> overload
> > >at the site. When you think of it you rarely transmit RF that close to
> the
> > >destination most of the time. We have found that distance and selecting
> > >locations that are best are about the only thing you can do in this
> case.
> > >It usually only happens when you are very close to the node. If this is
> > >your problem the only thing you can do is change locations of equipment
> or
> > >antennas and distance from your node.
> > >
> > >*73 Doug, WA3DSP*
> > >*http://wa3dsp.org <http://wa3dsp.org>*
> > >
> > >On Sun, Apr 26, 2020 at 11:57 AM "Chris Smart via ARM-allstar" <
> > >arm-allstar at hamvoip.org> wrote:
> > >
> > > > Thanks Doug.
> > > >
> > > >
> > > > What is typically the source of this hum? Wall-wart type power
> supplies?
> > > >
> > > > 73
> > > >
> > > >
> > > > Chris
> > > >
> > > >
> > > >
> > > > On 4/26/2020 10:46 AM, "Doug Crompton via ARM-allstar" wrote:
> > > > > Hum on local RF nodes is a common problem when transmitting TO
> your node.
> > > > > It is usually because you are too close to your node. If the hum
> stops
> > > > when
> > > > > you move to another location, sometimes just a foot or two one way
> or the
> > > > > other then that is probably the problem. It happens more often
> when using
> > > > > antennas that are mounted on the node itself. One way to get rid
> of it is
> > > > > to use those small mag mount antennas that have 10-15 feet of coax
> and
> > > > get
> > > > > it away from your operating position or use an outdoor antenna.
> Other
> > > > than
> > > > > that there is no filtering or other way to eliminate it. If the
> hum is
> > > > > constant at any location even walking hundreds of feet away then
> it is
> > > > not
> > > > > this phenomenon.
> > > > >
> > > > > *73 Doug, WA3DSP*
> > > > > *http://wa3dsp.org <http://wa3dsp.org>*
> > > > >
> > > > >
> > > > >
> > > > > On Sun, Apr 26, 2020 at 4:08 AM "Jed Barton via ARM-allstar" <
> > > > > arm-allstar at hamvoip.org> wrote:
> > > > >
> > > > >> Hey guys,
> > > > >>
> > > > >> So i'm sure i'm not the only 1 with this problem. I've got all my
> > > > >> allstar pies plugged in.  They each have their own power supply.
> It's
> > > > >> the typical wall wart.  They all produce a nice little hum that's
> just
> > > > >> annoying.
> > > > >> I'm sure a lot of you guys have delt with this.  You hear it on
> the
> > > > >> node transmitter such as the Shari.  Any ideas for getting rid of
> it,
> > > > >> or reducing it?
> > > > >>
> > > > >> Cheers,
> > > > >>
> > > > >> Jed
> > > > >> _______________________________________________
> > > > >>
> > > > >> ARM-allstar mailing list
> > > > >> ARM-allstar at hamvoip.org
> > > > >> http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > > >>
> > > > >> Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > > >>
> > > > > _______________________________________________
> > > > >
> > > > > ARM-allstar mailing list
> > > > > ARM-allstar at hamvoip.org
> > > > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > > >
> > > > > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > > _______________________________________________
> > > >
> > > > ARM-allstar mailing list
> > > > ARM-allstar at hamvoip.org
> > > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > >
> > > > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > >
> > >_______________________________________________
> > >
> > >ARM-allstar mailing list
> > >ARM-allstar at hamvoip.org
> > >http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > >
> > >Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> >
> > Mike Fleetwood
> > Canberra Australia and Sidcup UK.
> >
> > Worldwide email address is:     mfleetwood at gmail.com
> >
> > _______________________________________________
> >
> > ARM-allstar mailing list
> > ARM-allstar at hamvoip.org
> > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> >
> > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> >
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sun, 26 Apr 2020 18:15:04 -0400
> From: Doug Crompton <wa3dsp at gmail.com>
> To: ARM Allstar <arm-allstar at hamvoip.org>
> Subject: Re: [arm-allstar] hum on my allstar nodes
> Message-ID:
>         <
> CAMp6vstrGXLD9osGnwbMZNi1w2PpeNfihqFs5Vu5Kh2iTdXECA at mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> I can almost say with certainty that this is caused by EMI from the FOB
> and/or PI getting into the microphone. The mic has a 5V regulator and when
> you run it on 5V (vs the usual 8V on a Kenwood radio) the regulator does
> not regulate and instead passes all the 5V bus garbage to the high gain mic
> amp. This is very hard to get rid of with filtering. What has been done by
> some is use a 5V to 8V boost supply (they are very small) to boost the 5V
> back up to 8V for the mic. Then the regulator in the mic will function and
> it will eliminate the noise. I have heard them and they are very clean.
> This is also why we did not use Kenwood or Alinco mics on the the
> Technobygeorge radioless nodes but rather the Yaesu mics.
>
> *73 Doug, WA3DSP*
> *http://wa3dsp.org <http://wa3dsp.org>*
>
> On Sun, Apr 26, 2020 at 6:02 PM "Michael Fleetwood via ARM-allstar" <
> arm-allstar at hamvoip.org> wrote:
>
> > I am having a problem with a background hash others hear when I
> > transmit using a radioless node with a Pi3A+ an Alinco EMS57 mic,
> > modified sound fob and audio amp. Received audio is perfect, but when
> > I listen to myself on the parrot the noise sounds a bit like an FM
> > signal that is not fully quieting. I have tried optimising grounding
> > and using different power supplies including a 12v battery and 7805
> > regulator, but the problem persists.
> >
> > Mike
> > VK2AMF
> >
> >
> > At 05:23 AM 27/04/2020, you wrote:
> > >The "RF" hum is caused by some odd phasing relationship and/or RF
> overload
> > >at the site. When you think of it you rarely transmit RF that close to
> the
> > >destination most of the time. We have found that distance and selecting
> > >locations that are best are about the only thing you can do in this
> case.
> > >It usually only happens when you are very close to the node. If this is
> > >your problem the only thing you can do is change locations of equipment
> or
> > >antennas and distance from your node.
> > >
> > >*73 Doug, WA3DSP*
> > >*http://wa3dsp.org <http://wa3dsp.org>*
> > >
> > >On Sun, Apr 26, 2020 at 11:57 AM "Chris Smart via ARM-allstar" <
> > >arm-allstar at hamvoip.org> wrote:
> > >
> > > > Thanks Doug.
> > > >
> > > >
> > > > What is typically the source of this hum? Wall-wart type power
> > supplies?
> > > >
> > > > 73
> > > >
> > > >
> > > > Chris
> > > >
> > > >
> > > >
> > > > On 4/26/2020 10:46 AM, "Doug Crompton via ARM-allstar" wrote:
> > > > > Hum on local RF nodes is a common problem when transmitting TO your
> > node.
> > > > > It is usually because you are too close to your node. If the hum
> > stops
> > > > when
> > > > > you move to another location, sometimes just a foot or two one way
> > or the
> > > > > other then that is probably the problem. It happens more often when
> > using
> > > > > antennas that are mounted on the node itself. One way to get rid of
> > it is
> > > > > to use those small mag mount antennas that have 10-15 feet of coax
> > and
> > > > get
> > > > > it away from your operating position or use an outdoor antenna.
> Other
> > > > than
> > > > > that there is no filtering or other way to eliminate it. If the hum
> > is
> > > > > constant at any location even walking hundreds of feet away then it
> > is
> > > > not
> > > > > this phenomenon.
> > > > >
> > > > > *73 Doug, WA3DSP*
> > > > > *http://wa3dsp.org <http://wa3dsp.org>*
> > > > >
> > > > >
> > > > >
> > > > > On Sun, Apr 26, 2020 at 4:08 AM "Jed Barton via ARM-allstar" <
> > > > > arm-allstar at hamvoip.org> wrote:
> > > > >
> > > > >> Hey guys,
> > > > >>
> > > > >> So i'm sure i'm not the only 1 with this problem. I've got all my
> > > > >> allstar pies plugged in.  They each have their own power supply.
> > It's
> > > > >> the typical wall wart.  They all produce a nice little hum that's
> > just
> > > > >> annoying.
> > > > >> I'm sure a lot of you guys have delt with this.  You hear it on
> the
> > > > >> node transmitter such as the Shari.  Any ideas for getting rid of
> > it,
> > > > >> or reducing it?
> > > > >>
> > > > >> Cheers,
> > > > >>
> > > > >> Jed
> > > > >> _______________________________________________
> > > > >>
> > > > >> ARM-allstar mailing list
> > > > >> ARM-allstar at hamvoip.org
> > > > >> http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > > >>
> > > > >> Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > > >>
> > > > > _______________________________________________
> > > > >
> > > > > ARM-allstar mailing list
> > > > > ARM-allstar at hamvoip.org
> > > > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > > >
> > > > > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > > _______________________________________________
> > > >
> > > > ARM-allstar mailing list
> > > > ARM-allstar at hamvoip.org
> > > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > >
> > > > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > >
> > >_______________________________________________
> > >
> > >ARM-allstar mailing list
> > >ARM-allstar at hamvoip.org
> > >http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > >
> > >Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> >
> > Mike Fleetwood
> > Canberra Australia and Sidcup UK.
> >
> > Worldwide email address is:     mfleetwood at gmail.com
> >
> > _______________________________________________
> >
> > ARM-allstar mailing list
> > ARM-allstar at hamvoip.org
> > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> >
> > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> >
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 27 Apr 2020 08:26:34 +1000
> From: Michael Fleetwood <mfleetwood at gmail.com>
> To: ARM Allstar <arm-allstar at hamvoip.org>
> Subject: Re: [arm-allstar] hum on my allstar nodes
> Message-ID: <5ea60bba.1c69fb81.873ee.48ec at mx.google.com>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
>
> I do have a Yaesu MH-48 which I have not yet tried, mainly because I
> thought the Alinco was supposed to run at 5v which would be convenient.
>
> What voltage would be optimal to feed to the Alinco, and the Yaesu
> mics and I can see about producing that.
>
> Many thanks for your kind advice.
>
> Mike
> VK2AMF.
>
> At 08:15 AM 27/04/2020, you wrote:
> >I can almost say with certainty that this is caused by EMI from the FOB
> >and/or PI getting into the microphone. The mic has a 5V regulator and when
> >you run it on 5V (vs the usual 8V on a Kenwood radio) the regulator does
> >not regulate and instead passes all the 5V bus garbage to the high gain
> mic
> >amp. This is very hard to get rid of with filtering. What has been done by
> >some is use a 5V to 8V boost supply (they are very small) to boost the 5V
> >back up to 8V for the mic. Then the regulator in the mic will function and
> >it will eliminate the noise. I have heard them and they are very clean.
> >This is also why we did not use Kenwood or Alinco mics on the the
> >Technobygeorge radioless nodes but rather the Yaesu mics.
> >
> >*73 Doug, WA3DSP*
> >*http://wa3dsp.org <http://wa3dsp.org>*
> >
> >On Sun, Apr 26, 2020 at 6:02 PM "Michael Fleetwood via ARM-allstar" <
> >arm-allstar at hamvoip.org> wrote:
> >
> > > I am having a problem with a background hash others hear when I
> > > transmit using a radioless node with a Pi3A+ an Alinco EMS57 mic,
> > > modified sound fob and audio amp. Received audio is perfect, but when
> > > I listen to myself on the parrot the noise sounds a bit like an FM
> > > signal that is not fully quieting. I have tried optimising grounding
> > > and using different power supplies including a 12v battery and 7805
> > > regulator, but the problem persists.
> > >
> > > Mike
> > > VK2AMF
> > >
> > >
> > > At 05:23 AM 27/04/2020, you wrote:
> > > >The "RF" hum is caused by some odd phasing relationship and/or RF
> overload
> > > >at the site. When you think of it you rarely transmit RF that close
> to the
> > > >destination most of the time. We have found that distance and
> selecting
> > > >locations that are best are about the only thing you can do in this
> case.
> > > >It usually only happens when you are very close to the node. If this
> is
> > > >your problem the only thing you can do is change locations of
> equipment or
> > > >antennas and distance from your node.
> > > >
> > > >*73 Doug, WA3DSP*
> > > >*http://wa3dsp.org <http://wa3dsp.org>*
> > > >
> > > >On Sun, Apr 26, 2020 at 11:57 AM "Chris Smart via ARM-allstar" <
> > > >arm-allstar at hamvoip.org> wrote:
> > > >
> > > > > Thanks Doug.
> > > > >
> > > > >
> > > > > What is typically the source of this hum? Wall-wart type power
> > > supplies?
> > > > >
> > > > > 73
> > > > >
> > > > >
> > > > > Chris
> > > > >
> > > > >
> > > > >
> > > > > On 4/26/2020 10:46 AM, "Doug Crompton via ARM-allstar" wrote:
> > > > > > Hum on local RF nodes is a common problem when transmitting TO
> your
> > > node.
> > > > > > It is usually because you are too close to your node. If the hum
> > > stops
> > > > > when
> > > > > > you move to another location, sometimes just a foot or two one
> way
> > > or the
> > > > > > other then that is probably the problem. It happens more often
> when
> > > using
> > > > > > antennas that are mounted on the node itself. One way to get rid
> of
> > > it is
> > > > > > to use those small mag mount antennas that have 10-15 feet of
> coax
> > > and
> > > > > get
> > > > > > it away from your operating position or use an outdoor antenna.
> Other
> > > > > than
> > > > > > that there is no filtering or other way to eliminate it. If the
> hum
> > > is
> > > > > > constant at any location even walking hundreds of feet away then
> it
> > > is
> > > > > not
> > > > > > this phenomenon.
> > > > > >
> > > > > > *73 Doug, WA3DSP*
> > > > > > *http://wa3dsp.org <http://wa3dsp.org>*
> > > > > >
> > > > > >
> > > > > >
> > > > > > On Sun, Apr 26, 2020 at 4:08 AM "Jed Barton via ARM-allstar" <
> > > > > > arm-allstar at hamvoip.org> wrote:
> > > > > >
> > > > > >> Hey guys,
> > > > > >>
> > > > > >> So i'm sure i'm not the only 1 with this problem. I've got all
> my
> > > > > >> allstar pies plugged in.  They each have their own power supply.
> > > It's
> > > > > >> the typical wall wart.  They all produce a nice little hum
> that's
> > > just
> > > > > >> annoying.
> > > > > >> I'm sure a lot of you guys have delt with this.  You hear it on
> the
> > > > > >> node transmitter such as the Shari.  Any ideas for getting rid
> of
> > > it,
> > > > > >> or reducing it?
> > > > > >>
> > > > > >> Cheers,
> > > > > >>
> > > > > >> Jed
> > > > > >> _______________________________________________
> > > > > >>
> > > > > >> ARM-allstar mailing list
> > > > > >> ARM-allstar at hamvoip.org
> > > > > >> http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > > > >>
> > > > > >> Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > > > >>
> > > > > > _______________________________________________
> > > > > >
> > > > > > ARM-allstar mailing list
> > > > > > ARM-allstar at hamvoip.org
> > > > > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > > > >
> > > > > > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > > > _______________________________________________
> > > > >
> > > > > ARM-allstar mailing list
> > > > > ARM-allstar at hamvoip.org
> > > > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > > >
> > > > > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > > >
> > > >_______________________________________________
> > > >
> > > >ARM-allstar mailing list
> > > >ARM-allstar at hamvoip.org
> > > >http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > >
> > > >Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > >
> > > Mike Fleetwood
> > > Canberra Australia and Sidcup UK.
> > >
> > > Worldwide email address is:     mfleetwood at gmail.com
> > >
> > > _______________________________________________
> > >
> > > ARM-allstar mailing list
> > > ARM-allstar at hamvoip.org
> > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > >
> > > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > >
> >_______________________________________________
> >
> >ARM-allstar mailing list
> >ARM-allstar at hamvoip.org
> >http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> >
> >Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
>
> Mike Fleetwood
> Canberra Australia and Sidcup UK.
>
> Worldwide email address is:     mfleetwood at gmail.com
>
>
>
> ------------------------------
>
> Message: 4
> Date: Sun, 26 Apr 2020 21:06:40 -0400
> From: Chris Smart <csmart8 at cogeco.ca>
> To: Patrick Perdue via ARM-allstar <arm-allstar at hamvoip.org>
> Subject: Re: [arm-allstar] ARM-allstar Digest, Vol 71, Issue 59
> Message-ID: <72c2ee6b-bdfe-d7cb-cac6-a0a303ef4b37 at cogeco.ca>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> Yep, I'm going to ask for that on my next one.
>
>
>
> On 4/26/2020 6:00 PM, "Patrick Perdue via ARM-allstar" wrote:
> > That is exactly why I had G7RPG add an SMA connector to my Microhub
> > rather than using the internal antenna, so I could get the antenna
> > away from the Pi and the rest of the components.
> >
> > On 4/26/2020 4:54 PM, "Chris Smart via ARM-allstar" wrote:
> >> Thanks Ken. Very interesting. I'll pass this on to the guy who built
> >> my node.
> >>
> >>
> >>
> >> On 4/26/2020 12:57 PM, "Ken via ARM-allstar" wrote:
> >>> Hum is often caused by some AC current flowing through the 0 vdc
> >>> side of
> >>> whatever audio fob you are using. Voltage drop in the zero-volt
> >>> wiring of
> >>> the USB/fob connection is effectively in series with both the
> >>> transmit and
> >>> receive audio path.? A wall wart almost always puts some 60/120 Hz
> >>> AC on the
> >>> DC minus lead (relative to ground elsewhere on your system) and the
> >>> USB fob
> >>> offers no isolation for this.
> >>>
> >>> If you can figure out how to do it, the cheap answer is to connect a
> >>> short/heavy wire from the DC minus lead of your RPI 5 volt supply to
> >>> the DC
> >>> minus side of your radio's power supply.? These are the two sources
> >>> of the
> >>> unwanted AC.? Second-best is to connect a short/heavy wire from some
> >>> 0 volt
> >>> on the RPI to the chassis of your radio.? That is the critical part
> >>> of the
> >>> circuit.
> >>>
> >>> Using a 12/5 volt DC/DC converter to power the RPI also helps (using
> >>> the
> >>> same 12 volts as supplying your radio).
> >>>
> >>> Ken
> >>>
> >>>
> >>>
> >>>
> >>> ----------------------------------------------------------------------
> >>>
> >>> Message: 1
> >>> Date: Sun, 26 Apr 2020 04:04:45 -0400
> >>> From: Jed Barton <jed at jedbarton.com>
> >>> To: arm-allstar at hamvoip.org
> >>> Subject: [arm-allstar] hum on my allstar nodes
> >>> Message-ID:
> >>> ????<
> CAOYEAerhpLL_neibghwjjS81bU_xt_cMo2cmWG_HR1rsO6R7cw at mail.gmail.com>
> >>>
> >>> Content-Type: text/plain; charset="UTF-8"
> >>>
> >>> Hey guys,
> >>>
> >>> So i'm sure i'm not the only 1 with this problem. I've got all my
> >>> allstar
> >>> pies plugged in.? They each have their own power supply. It's the
> >>> typical
> >>> wall wart.? They all produce a nice little hum that's just annoying.
> >>> I'm sure a lot of you guys have delt with this.? You hear it on the
> >>> node
> >>> transmitter such as the Shari.? Any ideas for getting rid of it, or
> >>> reducing
> >>> it?
> >>>
> >>> Cheers,
> >>>
> >>> Jed
> >>>
> >>>
> >>> _______________________________________________
> >>>
> >>> ARM-allstar mailing list
> >>> ARM-allstar at hamvoip.org
> >>> http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> >>>
> >>> Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> >> _______________________________________________
> >>
> >> ARM-allstar mailing list
> >> ARM-allstar at hamvoip.org
> >> http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> >>
> >> Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > _______________________________________________
> >
> > ARM-allstar mailing list
> > ARM-allstar at hamvoip.org
> > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> >
> > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
>
>
> ------------------------------
>
> Message: 5
> Date: Sun, 26 Apr 2020 22:42:33 -0400
> From: Doug Crompton <wa3dsp at gmail.com>
> To: ARM Allstar <arm-allstar at hamvoip.org>
> Subject: Re: [arm-allstar] hum on my allstar nodes
> Message-ID:
>         <
> CAMp6vsuAWdcNaR_nxBYsV9ze34KBben410yLqZg05LG6BewA-A at mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> Unfortunately Yaesu mics are not usable because they have no internal DTMF
> generator but rather a 4x5 XY resistance matrix. We used an Arduino to read
> the XY voltages and produce DTMF in the radioless node.
>
> The Kenwood/Alinco mics use 8V which is the standard output voltage on the
> mic jack of their radios. This is reduced to 5V in the mic with a
> regulator. You need at least 1.5 to 2 volts above that to regulate.
> Something like this -
>
> https://www.amazon.com/dp/B07RZT7J61/ref=sspa_dk_detail_3
>
> *73 Doug, WA3DSP*
> *http://wa3dsp.org <http://wa3dsp.org>*
>
> On Sun, Apr 26, 2020 at 6:34 PM "Michael Fleetwood via ARM-allstar" <
> arm-allstar at hamvoip.org> wrote:
>
> > I do have a Yaesu MH-48 which I have not yet tried, mainly because I
> > thought the Alinco was supposed to run at 5v which would be convenient.
> >
> > What voltage would be optimal to feed to the Alinco, and the Yaesu
> > mics and I can see about producing that.
> >
> > Many thanks for your kind advice.
> >
> > Mike
> > VK2AMF.
> >
> > At 08:15 AM 27/04/2020, you wrote:
> > >I can almost say with certainty that this is caused by EMI from the FOB
> > >and/or PI getting into the microphone. The mic has a 5V regulator and
> when
> > >you run it on 5V (vs the usual 8V on a Kenwood radio) the regulator does
> > >not regulate and instead passes all the 5V bus garbage to the high gain
> > mic
> > >amp. This is very hard to get rid of with filtering. What has been done
> by
> > >some is use a 5V to 8V boost supply (they are very small) to boost the
> 5V
> > >back up to 8V for the mic. Then the regulator in the mic will function
> and
> > >it will eliminate the noise. I have heard them and they are very clean.
> > >This is also why we did not use Kenwood or Alinco mics on the the
> > >Technobygeorge radioless nodes but rather the Yaesu mics.
> > >
> > >*73 Doug, WA3DSP*
> > >*http://wa3dsp.org <http://wa3dsp.org>*
> > >
> > >On Sun, Apr 26, 2020 at 6:02 PM "Michael Fleetwood via ARM-allstar" <
> > >arm-allstar at hamvoip.org> wrote:
> > >
> > > > I am having a problem with a background hash others hear when I
> > > > transmit using a radioless node with a Pi3A+ an Alinco EMS57 mic,
> > > > modified sound fob and audio amp. Received audio is perfect, but when
> > > > I listen to myself on the parrot the noise sounds a bit like an FM
> > > > signal that is not fully quieting. I have tried optimising grounding
> > > > and using different power supplies including a 12v battery and 7805
> > > > regulator, but the problem persists.
> > > >
> > > > Mike
> > > > VK2AMF
> > > >
> > > >
> > > > At 05:23 AM 27/04/2020, you wrote:
> > > > >The "RF" hum is caused by some odd phasing relationship and/or RF
> > overload
> > > > >at the site. When you think of it you rarely transmit RF that close
> > to the
> > > > >destination most of the time. We have found that distance and
> > selecting
> > > > >locations that are best are about the only thing you can do in this
> > case.
> > > > >It usually only happens when you are very close to the node. If this
> > is
> > > > >your problem the only thing you can do is change locations of
> > equipment or
> > > > >antennas and distance from your node.
> > > > >
> > > > >*73 Doug, WA3DSP*
> > > > >*http://wa3dsp.org <http://wa3dsp.org>*
> > > > >
> > > > >On Sun, Apr 26, 2020 at 11:57 AM "Chris Smart via ARM-allstar" <
> > > > >arm-allstar at hamvoip.org> wrote:
> > > > >
> > > > > > Thanks Doug.
> > > > > >
> > > > > >
> > > > > > What is typically the source of this hum? Wall-wart type power
> > > > supplies?
> > > > > >
> > > > > > 73
> > > > > >
> > > > > >
> > > > > > Chris
> > > > > >
> > > > > >
> > > > > >
> > > > > > On 4/26/2020 10:46 AM, "Doug Crompton via ARM-allstar" wrote:
> > > > > > > Hum on local RF nodes is a common problem when transmitting TO
> > your
> > > > node.
> > > > > > > It is usually because you are too close to your node. If the
> hum
> > > > stops
> > > > > > when
> > > > > > > you move to another location, sometimes just a foot or two one
> > way
> > > > or the
> > > > > > > other then that is probably the problem. It happens more often
> > when
> > > > using
> > > > > > > antennas that are mounted on the node itself. One way to get
> rid
> > of
> > > > it is
> > > > > > > to use those small mag mount antennas that have 10-15 feet of
> > coax
> > > > and
> > > > > > get
> > > > > > > it away from your operating position or use an outdoor antenna.
> > Other
> > > > > > than
> > > > > > > that there is no filtering or other way to eliminate it. If the
> > hum
> > > > is
> > > > > > > constant at any location even walking hundreds of feet away
> then
> > it
> > > > is
> > > > > > not
> > > > > > > this phenomenon.
> > > > > > >
> > > > > > > *73 Doug, WA3DSP*
> > > > > > > *http://wa3dsp.org <http://wa3dsp.org>*
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > On Sun, Apr 26, 2020 at 4:08 AM "Jed Barton via ARM-allstar" <
> > > > > > > arm-allstar at hamvoip.org> wrote:
> > > > > > >
> > > > > > >> Hey guys,
> > > > > > >>
> > > > > > >> So i'm sure i'm not the only 1 with this problem. I've got all
> > my
> > > > > > >> allstar pies plugged in.  They each have their own power
> supply.
> > > > It's
> > > > > > >> the typical wall wart.  They all produce a nice little hum
> > that's
> > > > just
> > > > > > >> annoying.
> > > > > > >> I'm sure a lot of you guys have delt with this.  You hear it
> on
> > the
> > > > > > >> node transmitter such as the Shari.  Any ideas for getting rid
> > of
> > > > it,
> > > > > > >> or reducing it?
> > > > > > >>
> > > > > > >> Cheers,
> > > > > > >>
> > > > > > >> Jed
> > > > > > >> _______________________________________________
> > > > > > >>
> > > > > > >> ARM-allstar mailing list
> > > > > > >> ARM-allstar at hamvoip.org
> > > > > > >> http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > > > > >>
> > > > > > >> Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > > > > >>
> > > > > > > _______________________________________________
> > > > > > >
> > > > > > > ARM-allstar mailing list
> > > > > > > ARM-allstar at hamvoip.org
> > > > > > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > > > > >
> > > > > > > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > > > > _______________________________________________
> > > > > >
> > > > > > ARM-allstar mailing list
> > > > > > ARM-allstar at hamvoip.org
> > > > > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > > > >
> > > > > > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > > > >
> > > > >_______________________________________________
> > > > >
> > > > >ARM-allstar mailing list
> > > > >ARM-allstar at hamvoip.org
> > > > >http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > > >
> > > > >Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > >
> > > > Mike Fleetwood
> > > > Canberra Australia and Sidcup UK.
> > > >
> > > > Worldwide email address is:     mfleetwood at gmail.com
> > > >
> > > > _______________________________________________
> > > >
> > > > ARM-allstar mailing list
> > > > ARM-allstar at hamvoip.org
> > > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > >
> > > > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > > >
> > >_______________________________________________
> > >
> > >ARM-allstar mailing list
> > >ARM-allstar at hamvoip.org
> > >http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > >
> > >Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> >
> > Mike Fleetwood
> > Canberra Australia and Sidcup UK.
> >
> > Worldwide email address is:     mfleetwood at gmail.com
> >
> > _______________________________________________
> >
> > ARM-allstar mailing list
> > ARM-allstar at hamvoip.org
> > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> >
> > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> >
>
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
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> ARM-allstar at hamvoip.org
> http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
>
>
> ------------------------------
>
> End of ARM-allstar Digest, Vol 71, Issue 61
> *******************************************
>

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