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
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@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 _________________________________________ 44Net mailing list 44Net@mailman.ampr.org https://mailman.ampr.org/mailman/listinfo/44net
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
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 _________________________________________ 44Net mailing list 44Net@mailman.ampr.org https://mailman.ampr.org/mailman/listinfo/44net
-
Marius Petrescu -
Michael Fox (N6MEF) -
Rob PE1CHL -
Toussaint OTTAVI