2 Jan
2022
2 Jan
'22
10:18 a.m.
Are you distributing square waves or sine waves?
Not sure why use cat5 for the distribution?
RG58 and BNC is inexpensive, and conventional. And was up to date for networking in 1990
;)
I bet RG6 and F connectors would work, caveat being stay away from lengths that would
transform 50 ohm impedance.
Does that really matter? I looked at my sources through a long RG59 lab cable; no
discernable difference vs RG58
I use DEMI distribution amplifiers. 1 in, 4 out (star), MAR-1 MMIC amps and good
filtering really cleans up the input. For example, several of my OCXOs have measurable 2x
and 3x harmonics, the DEMI really cleans up the signal.
This is a fascinating area. If you haven't already, subscribe to the "time
nuts" email list.
Cliff K6CLS CM87
On January 2, 2022 7:27:50 AM PST, Toussaint OTTAVI via 44Net
<44net(a)mailman.ampr.org> wrote:
Le 02/01/2022 à 15:50, Bill Buhler a écrit :
Impedance, cat3-> cat6 cabling Impedance is 100 ohms
$1 Chinese adapters seem to be direct-connect of the coax connector to
pins 1-2 of RJ45, HI :-) Anyway, it's just a matter of 2:1 balun, so it
should be doable easily.
Topology, twisted pair is normally run in a star configuration, but
that requires a Impedance matching hub in the middle. You'll need to
design and add that to drive multiple devices.
Some existing GPSDO already have several outputs, that should not be a
problem. I won't redesign the GPSDO from scratch, I'll probably
integrate some existing modules around a RPi or ESP8266 for management.
I've never seen a cheap cat45 to f converter that actually had the
right circuits to be clean.
I saw adapters called "baluns" for satellite distribution over RJ45 on
electrical equipment catalogs. But if they really contain a balun, it
would be for 75 Ohms, so not usable directly.
The other (maybe promising) idea would be to use fiber adapters, that
would in the meantime avoid RFI, QRM and ligntning...
Good luck, it sounds like a fun project...
My interest is mostly in digital modes, computing, SDR, satellite,
etc... Most of those things require frequency stability, so having a 10
MHz signal available everywhere in the shack seems to be something
future-proof :-)
Moreover, "HF over fiber" is also something I am interested in for the
future. If the lightning strikes, I'd prefer it to stay outside of the
shack :-) Carrying 10 MHz over fiber may be a good start point.
73 de TK1BI
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