2 Jan
2022
2 Jan
'22
9:17 a.m.
Hi all,
(Here's my full post, one line disappeared in the previous one)
I'm thinking about building a GPS-disciplined 10 MHz reference
oscillator. Of course, I'd like to add some networking features to it :-)
NTP server is the most obvious, and is well documented.
But I'd like to be able to carry 10 MHz reference signal to various
locations in the shack over network cabling. My first idea is about
using existing converters for TV/SAT :
- RF to Ethernet passive couplers (a F connector tied to pins 1-2 of a
RJ45 connector, $1 on Chinese warehouses).
- RF to fiber adapters (such as those used in FTTH/CATV). But a first
look shows frequency range is 50-1000 MHz.
Anyway, I do not have any idea about whether it will work or not while
maintaining the reference/stability purpose of the 10 MHz signal.
Any suggestions ?
HNY & 73 de TK1BI
2 Jan
2 Jan
12:54 p.m.
For that level of accuracy you’ll need SyncE (for frequency sync) or PTP (IEEE 1588) (for
frequency and phase sync).
Michael
N6MEF
Sent from my iPhone
On Jan 2, 2022, at 08:17, Toussaint OTTAVI via 44Net
<44net(a)mailman.ampr.org> wrote:
Hi all,
(Here's my full post, one line disappeared in the previous one)
I'm thinking about building a GPS-disciplined 10 MHz reference oscillator. Of course,
I'd like to add some networking features to it :-)
NTP server is the most obvious, and is well documented.
But I'd like to be able to carry 10 MHz reference signal to various locations in the
shack over network cabling. My first idea is about using existing converters for TV/SAT :
- RF to Ethernet passive couplers (a F connector tied to pins 1-2 of a RJ45 connector, $1
on Chinese warehouses).
- RF to fiber adapters (such as those used in FTTH/CATV). But a first look shows
frequency range is 50-1000 MHz.
Anyway, I do not have any idea about whether it will work or not while maintaining the
reference/stability purpose of the 10 MHz signal.
Any suggestions ?
HNY & 73 de TK1BI
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12:59 p.m.
On 1/2/22 3:17 PM, Toussaint OTTAVI via 44Net wrote:
But I'd like to be able to carry 10 MHz reference signal to various locations in the
shack over network cabling. My first idea is about using existing converters for TV/SAT :
- RF to Ethernet passive couplers (a F connector tied to pins 1-2 of a RJ45 connector, $1
on Chinese warehouses).
- RF to fiber adapters (such as those used in FTTH/CATV). But a first look shows
frequency range is 50-1000 MHz.
I have not handled that particular scenario. What we have done (at least temporarily):
- used commercial "video distribution amplifiers" from the old analog video days
to split the 10 MHz signal over several coax outputs. works fine.
- used "coax to utp baluns" from China (intended to use oldfashioned analog
cameras over UTP wiring). also worked fine while we needed it. I think that is what you
meant with the first option?
So I guess the combination of these two will also work.
Video stuff is of course specifiied for the 0-6 MHz range but as long as there is no
intentional lowpass filter in them, it will work at 10 MHz.
Of course the CATV baluns do not work well for the purpose they are intended for, but for
10 MHz it does not really matter.
But I think using coax is the better option, it tends to radiate (and pickup interference)
less than UTP.
Rob
4:39 p.m.
Regarding distribution by fiber optics, that should also be no problem.
But you kind of need to build your own system.
Take a look at SPDIF/TOSLINK optical emitters and receivers. There are
low cost modules available for up to 10Mbps using standard 650nm TOSLINK
plastic fibers (e.g. TORX/TOTX 135XA series from Toshiba at a cost
around 25 euro a pair). Since you only need to transport a reference
clock, basically a square wave, there should not be a problem using them
in an extreme simple schematics for distances up to a few tens of meters.
But of course, costs will not be in the 1€ rand like the Alibaba balun.
But there are also Chinese sources going down to less than $1 per
optical transceiver in a 100pcs range.
Marius, YO2LOJ
On 02/01/2022 19:59, Rob PE1CHL via 44Net wrote:
On 1/2/22 3:17 PM, Toussaint OTTAVI via 44Net wrote:
But I'd like to be able to carry 10 MHz
reference signal to various locations in the shack over network cabling. My first idea is
about using existing converters for TV/SAT :
- RF to Ethernet passive couplers (a F connector tied to pins 1-2 of a RJ45 connector, $1
on Chinese warehouses).
- RF to fiber adapters (such as those used in FTTH/CATV). But a first look shows
frequency range is 50-1000 MHz.
I have not handled that particular scenario. What
we have done (at least temporarily):
- used commercial "video distribution amplifiers" from the old analog video
days to split the 10 MHz signal over several coax outputs. works fine.
- used "coax to utp baluns" from China (intended to use oldfashioned analog
cameras over UTP wiring). also worked fine while we needed it. I think that is what you
meant with the first option?
So I guess the combination of these two will also work.
Video stuff is of course specifiied for the 0-6 MHz range but as long as there is no
intentional lowpass filter in them, it will work at 10 MHz.
Of course the CATV baluns do not work well for the purpose they are intended for, but for
10 MHz it does not really matter.
But I think using coax is the better option, it tends to radiate (and pickup
interference) less than UTP.
Rob
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3 comments
4 participants
participants (4)
-
Marius Petrescu -
Michael Fox (N6MEF) -
Rob PE1CHL -
Toussaint OTTAVI