[App_rpt-users] App_rpt-users Digest, Vol 88, Issue 16
Joe Leikhim
rhyolite at leikhim.com
Mon Jun 6 16:59:27 UTC 2016
There was mention on this board that drift of the 9.6 MHz clock causes
the CTCSS phase to shift. If this is the case, you will have audible
noise and possibly receiver CTCSS drop outs in overlap areas. You will
have distortion of audio frequencies as well.
Whatever solution to the 9.6 MHz clock must be phase coherent between
RTCM nodes .
I have no experience with RTCM, but am quite familiar with commercial
simulcast in the LMR world. I am lurking here because I see the RTCM as
a very affordable contender to the commercial products that exist today.
Joe K4SAT
On 6/6/2016 12:23 PM, Jeff Carrier wrote:
> The RTCM and simulcast DOES work. As mentioned before, you have to be
> using a transmitter that can accept a 10 mHz (or whatever) reference
> signal. You also need 1 PPS for your receivers and transmitter. You
> also need to sync the RTCM to your GPSDO (which I have not done). If
> you have not done all this you WILL hear some "funk" in the overlap
> areas.
>
> That "funk" can go from usable to un-usable depending on how strong
> the transmitters are in the overlap region.
>
> Pardon the "non-technical" terms. It does work but the law of physics
> do apply here.
>
> de K0JSC
>
> On Mon, Jun 6, 2016 at 9:54 AM, <app_rpt-users-request at ohnosec.org
> <mailto:app_rpt-users-request at ohnosec.org>> wrote:
>
> Send App_rpt-users mailing list submissions to
> app_rpt-users at ohnosec.org <mailto:app_rpt-users at ohnosec.org>
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
> or, via email, send a message with subject or body 'help' to
> app_rpt-users-request at ohnosec.org
> <mailto:app_rpt-users-request at ohnosec.org>
>
> You can reach the person managing the list at
> app_rpt-users-owner at ohnosec.org
> <mailto:app_rpt-users-owner at ohnosec.org>
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of App_rpt-users digest..."
>
>
> Today's Topics:
>
> 1. Re: audio for direct VCO FM (Joe Leikhim) (Steve Wright)
> 2. Re: RTCM Simulcast question (Steve Wright)
> 3. Re: audio for direct VCO FM: Si5351B (David McGough)
> 4. Re: RTCM Simulcast question (Joe Moskalski)
> 5. Re: RTCM Simulcast question (David McGough)
> 6. Re: RTCM Simulcast question (Joe Moskalski)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 6 Jun 2016 19:40:50 +1200
> From: Steve Wright <info at meshnetworks.co.nz
> <mailto:info at meshnetworks.co.nz>>
> To: app_rpt-users at ohnosec.org <mailto:app_rpt-users at ohnosec.org>
> Subject: Re: [App_rpt-users] audio for direct VCO FM (Joe Leikhim)
> Message-ID: <57552902.9070008 at meshnetworks.co.nz
> <mailto:57552902.9070008 at meshnetworks.co.nz>>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> On 04/06/16 04:00, Joe Leikhim <rhyolite at leikhim.com
> <mailto:rhyolite at leikhim.com>> wrote:
> > Assuming the VCO is part of a PLL, the PLL will tend to
> "correct" the
> > modulation, [....]
>
> Was planning to use the Si5351B - has VCO input.
>
> S
>
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 6 Jun 2016 20:22:36 +1200
> From: Steve Wright <info at meshnetworks.co.nz
> <mailto:info at meshnetworks.co.nz>>
> To: app_rpt-users at ohnosec.org <mailto:app_rpt-users at ohnosec.org>
> Subject: Re: [App_rpt-users] RTCM Simulcast question
> Message-ID: <575532CC.2020304 at meshnetworks.co.nz
> <mailto:575532CC.2020304 at meshnetworks.co.nz>>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> On Sat, Jun 4, 2016 at 6:03 PM, Joe Moskalski <kc2irv at gmail.com
> <mailto:kc2irv at gmail.com>> wrote:
>
> > I will be setting up a 2 site UHF simulcast system in the coming
> months
>
> Huh? I was told (on this list) that simulcast TX "doesn't work".
>
>
>
> S
>
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 6 Jun 2016 10:46:38 -0400 (EDT)
> From: David McGough <kb4fxc at inttek.net <mailto:kb4fxc at inttek.net>>
> To: app_rpt-users at ohnosec.org <mailto:app_rpt-users at ohnosec.org>
> Subject: Re: [App_rpt-users] audio for direct VCO FM: Si5351B
> Message-ID:
>
> <Pine.LNX.4.44.1606060946450.4196-100000 at goliath.inttek.net
> <mailto:Pine.LNX.4.44.1606060946450.4196-100000 at goliath.inttek.net>>
> Content-Type: TEXT/PLAIN; charset=US-ASCII
>
>
> Hi Steve,
>
> We're getting way off topic for the mailing list, but, I thought
> I'd post
> this reply here if there are any other interested hams out there,
> perhaps
> who are also experimenting in this area.
>
> I haven't played with the Si5351B version of this interesting
> chip, yet. I
> wonder whether the voltage control input of this chip would be
> suitable
> for AF FM modulation? Assuming that you could modulate the VCXO at
> audio
> frequencies (the datasheet isn't completely clear to me about
> that), an
> immediate issue would be that everytime you change the fractional-N
> division ratio, you'll change the modulation index. This will have
> to be
> compensated for, one way or another.
>
> I've been playing with several boards with Si5351 chips. They're
> pretty
> neat. They're also pretty noisy! ...With both spurious and phase
> noise.
> The phase noise can be improved somewhat with a better external
> crystal
> oscillator, the spurs seem more challenging. Using the on-board
> VCXO with
> the 5351B, you can't use a high quality external oscillator, so phase
> noise and overall frequency stability could be an issue, too.
>
> Anyhow, for my applications, I'm following the Si5351 with a secondary
> clean-up VCO/PLL, which was already in the radios. I just needed a
> frequency-agile reference oscillator, so to speak. I think the
> Si5351 will
> work well for this, based on my preliminary tests! (I'd certainly
> like to
> hear the experiences from anyone who has already been down this road!)
>
> I guess you're not finding any local sources of surplus radios?
> Do you
> have any 6m power amps available?
>
>
> 73, David KB4FXC
>
>
>
> On Mon, 6 Jun 2016, Steve Wright wrote:
>
> > On 04/06/16 04:00, Joe Leikhim <rhyolite at leikhim.com
> <mailto:rhyolite at leikhim.com>> wrote:
> > > Assuming the VCO is part of a PLL, the PLL will tend to
> "correct" the
> > > modulation, [....]
> >
> > Was planning to use the Si5351B - has VCO input.
> >
> > S
> >
>
>
>
> ------------------------------
>
> Message: 4
> Date: Mon, 6 Jun 2016 11:03:11 -0400
> From: Joe Moskalski <kc2irv at gmail.com <mailto:kc2irv at gmail.com>>
> To: App_rpt-users at ohnosec.org <mailto:App_rpt-users at ohnosec.org>
> Subject: Re: [App_rpt-users] RTCM Simulcast question
> Message-ID:
>
> <CAES28qxB06niu+nL4Y5QfUvgZFf-y8s=uZdH2afzxKnwr0HV+w at mail.gmail.com
> <mailto:uZdH2afzxKnwr0HV%2Bw at mail.gmail.com>>
> Content-Type: text/plain; charset="utf-8"
>
> > It seems clear that in order for simulcast to work properly with
> the RTCM
> > I will need to clock the CPU to the GPSDO. Is there a device
> available to
> > give you the 9.6 mhz reference from the 10 mhz out from the
> GPSDO or does
> > anyone have a schematic available so that I can build them myself?
> >
> >
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon>
> Virus-free.
> www.avast.com <http://www.avast.com>
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link>
> <#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL:
> <http://ohnosec.org/pipermail/app_rpt-users/attachments/20160606/a36d4626/attachment-0001.html>
>
> ------------------------------
>
> Message: 5
> Date: Mon, 6 Jun 2016 11:36:01 -0400 (EDT)
> From: David McGough <kb4fxc at inttek.net <mailto:kb4fxc at inttek.net>>
> To: App_rpt-users at ohnosec.org <mailto:App_rpt-users at ohnosec.org>
> Subject: Re: [App_rpt-users] RTCM Simulcast question
> Message-ID:
>
> <Pine.LNX.4.44.1606061122550.4196-100000 at goliath.inttek.net
> <mailto:Pine.LNX.4.44.1606061122550.4196-100000 at goliath.inttek.net>>
> Content-Type: TEXT/PLAIN; charset=US-ASCII
>
>
> Hi Joe,
>
> While on the subject of the Si5351 chips, the application of
> converting
> one reference clock to a secondary frequency is what they were
> designed
> for. So, since you've already got a GPS reference, this -might- be an
> inexpensive starting point...For this application, you obviously won't
> need all the bells and whistles presented in this article! See:
>
> http://www.knology.net/~gmarcus/Si5351/Si5351_VFO_QEX.pdf
> <http://www.knology.net/%7Egmarcus/Si5351/Si5351_VFO_QEX.pdf>
> http://www.knology.net/~gmarcus <http://www.knology.net/%7Egmarcus>
>
> Note that I would replace the Si5351 25MHz reference with a decent
> TCXO
> (available on ebay, etc.)....Note that I haven't used the Si5351
> with an
> RTCM, there may be simpler/better ways???
>
>
> 73, David KB4FXC
>
>
>
>
> On Mon, 6 Jun 2016, Joe Moskalski wrote:
>
> > > It seems clear that in order for simulcast to work properly
> with the RTCM
> > > I will need to clock the CPU to the GPSDO. Is there a device
> available to
> > > give you the 9.6 mhz reference from the 10 mhz out from the
> GPSDO or does
> > > anyone have a schematic available so that I can build them myself?
> > >
> > >
> >
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon>
> > Virus-free.
> > www.avast.com <http://www.avast.com>
> >
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link>
> > <#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
> >
>
>
>
> ------------------------------
>
> Message: 6
> Date: Mon, 6 Jun 2016 11:54:11 -0400
> From: Joe Moskalski <kc2irv at gmail.com <mailto:kc2irv at gmail.com>>
> To: David McGough <kb4fxc at inttek.net <mailto:kb4fxc at inttek.net>>
> Cc: App_rpt-users at ohnosec.org <mailto:App_rpt-users at ohnosec.org>
> Subject: Re: [App_rpt-users] RTCM Simulcast question
> Message-ID:
>
> <CAES28qx-G3wytTXKMRVvzMNm+498_c-aeNB6JrTWmZOR7A7ZcA at mail.gmail.com
> <mailto:CAES28qx-G3wytTXKMRVvzMNm%2B498_c-aeNB6JrTWmZOR7A7ZcA at mail.gmail.com>>
> Content-Type: text/plain; charset="utf-8"
>
> I mentioned this to someone else, QRP Labs has a kit that creates
> a OCXO
> around the Si5351 chip. here is the link:
>
> http://www.qrp-labs.com/ocxokit.html
>
> If you couple this with another kit of theirs you can program it
> it any
> frequency you want. My only thought is would it be accurate/stable
> enough.
>
> http://www.qrp-labs.com/progrock.html
>
>
>
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon>
> Virus-free.
> www.avast.com <http://www.avast.com>
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link>
> <#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
> On Mon, Jun 6, 2016 at 11:36 AM, David McGough <kb4fxc at inttek.net
> <mailto:kb4fxc at inttek.net>> wrote:
>
> >
> > Hi Joe,
> >
> > While on the subject of the Si5351 chips, the application of
> converting
> > one reference clock to a secondary frequency is what they were
> designed
> > for. So, since you've already got a GPS reference, this -might-
> be an
> > inexpensive starting point...For this application, you obviously
> won't
> > need all the bells and whistles presented in this article! See:
> >
> > http://www.knology.net/~gmarcus/Si5351/Si5351_VFO_QEX.pdf
> <http://www.knology.net/%7Egmarcus/Si5351/Si5351_VFO_QEX.pdf>
> > http://www.knology.net/~gmarcus <http://www.knology.net/%7Egmarcus>
> >
> > Note that I would replace the Si5351 25MHz reference with a
> decent TCXO
> > (available on ebay, etc.)....Note that I haven't used the Si5351
> with an
> > RTCM, there may be simpler/better ways???
> >
> >
> > 73, David KB4FXC
> >
> >
> >
> >
> > On Mon, 6 Jun 2016, Joe Moskalski wrote:
> >
> > > > It seems clear that in order for simulcast to work properly
> with the
> > RTCM
> > > > I will need to clock the CPU to the GPSDO. Is there a device
> available
> > to
> > > > give you the 9.6 mhz reference from the 10 mhz out from the
> GPSDO or
> > does
> > > > anyone have a schematic available so that I can build them
> myself?
> > > >
> > > >
> > > <
> >
> https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon
> > >
> > > Virus-free.
> > > www.avast.com <http://www.avast.com>
> > > <
> >
> https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link
> > >
> > > <#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
> > >
> >
> > _______________________________________________
> > App_rpt-users mailing list
> > App_rpt-users at ohnosec.org <mailto:App_rpt-users at ohnosec.org>
> > http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
> >
> > To unsubscribe from this list please visit
> > http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and
> scroll down
> > to the bottom of the page. Enter your email address and press the
> > "Unsubscribe or edit options button"
> > You do not need a password to unsubscribe, you can do it via email
> > confirmation. If you have trouble unsubscribing, please send a
> message to
> > the list detailing the problem.
> >
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL:
> <http://ohnosec.org/pipermail/app_rpt-users/attachments/20160606/a06570ac/attachment.html>
>
> ------------------------------
>
> _______________________________________________
> App_rpt-users mailing list
> App_rpt-users at ohnosec.org <mailto:App_rpt-users at ohnosec.org>
> http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
>
>
> End of App_rpt-users Digest, Vol 88, Issue 16
> *********************************************
>
>
>
>
> _______________________________________________
> App_rpt-users mailing list
> App_rpt-users at ohnosec.org
> http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
>
> To unsubscribe from this list please visit http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the "Unsubscribe or edit options button"
> You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.
--
Joe Leikhim
Leikhim and Associates
Communications Consultants
Oviedo, Florida
JLeikhim at Leikhim.com
407-982-0446
WWW.LEIKHIM.COM
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.keekles.org/pipermail/app_rpt-users/attachments/20160606/00c882a2/attachment.html>
More information about the App_rpt-users
mailing list