Montrose coax - Bewerkingsoverzicht

Thomas: some more stats

2018-10-24T19:41:27Z

some more stats

← Oudere versie		Versie van 24 okt 2018 19:41
Regel 30:		Regel 30:
	</gallery>		</gallery>

	== ~~to be added~~ ==		== Further measurements ==

	~~There's a plan to characterize the coax with a spectrum analyzer and a noise source~~.		Attenuation/100 meters:
			@26MHz=1.33dB,
			@50MHz=1.81dB,
			@70MHz=1.99dB,
			@145MHz=3.35dB.

Thomastheo op 30 sep 2017 om 20:31

2017-09-30T20:31:46Z

← Oudere versie		Versie van 30 sep 2017 20:31
Regel 7:		Regel 7:
	}}		}}

	One of our participants (gert) showed up with a load of old (but seemingly high quality) coaxial cable from a data center. There are other people online looking for info on this very same coax, but so far nothing is out there to be found. In an effort to remedy that, here's what we managed to figure out for ourselves.		One of our participants (thanks gert!) showed up with a load of old (but seemingly high quality) coaxial cable from a data center. There are other people online looking for info on this very same coax, but so far nothing is out there to be found. In an effort to remedy that, here's what we managed to figure out for ourselves.

	The cable is marked as follows:		The cable is marked as follows:

Thomastheo op 30 sep 2017 om 19:19

2017-09-30T19:19:28Z

← Oudere versie		Versie van 30 sep 2017 19:19
Regel 13:		Regel 13:
	MONTROSE / CDT 16 AWG (UL) CL2P SHIELDED COAXIAL 125C CSA CXC 60C FT4 & FT6		MONTROSE / CDT 16 AWG (UL) CL2P SHIELDED COAXIAL 125C CSA CXC 60C FT4 & FT6

	It's 50 ohm coax, ~~and~~ has a braid ~~and~~ foil shielding. The velocity factor is 0.85, suggesting a foam polyethylene dielectric. The exterior is supposedly UV resistant.		It's 50 ohm coax, it has a braid/foil shielding, and a stranded center conductor. The velocity factor is 0.85, suggesting a foam polyethylene dielectric. The exterior is supposedly UV resistant.

Thomastheo op 30 sep 2017 om 19:18

2017-09-30T19:18:14Z

← Oudere versie		Versie van 30 sep 2017 19:18
Regel 7:		Regel 7:
	}}		}}

	One of our participants (gert) showed up with a load of old (but seemingly high quality) coaxial cable from a data center. There are other people online looking for info on ~~the~~ very same ~~cable~~, but so far nothing is out there ~~on this stuff~~. In an effort to remedy that, here's what we managed to figure out		One of our participants (gert) showed up with a load of old (but seemingly high quality) coaxial cable from a data center. There are other people online looking for info on this very same coax, but so far nothing is out there to be found. In an effort to remedy that, here's what we managed to figure out for ourselves.

	The cable is marked as follows:		The cable is marked as follows:
Regel 29:		Regel 29:

	</gallery>		</gallery>

			== to be added ==

			There's a plan to characterize the coax with a spectrum analyzer and a noise source.

Thomastheo op 30 sep 2017 om 17:46

2017-09-30T17:46:51Z

← Oudere versie		Versie van 30 sep 2017 17:46
Regel 6:		Regel 6:
	\|Contact=thomas		\|Contact=thomas
	}}		}}


	One of our participants (gert) showed up with a load of old (but seemingly high quality) coaxial cable from a data center. There are other people online looking for info on the very same cable, but so far nothing is out there on this stuff. In an effort to remedy that, here's what we managed to figure out		One of our participants (gert) showed up with a load of old (but seemingly high quality) coaxial cable from a data center. There are other people online looking for info on the very same cable, but so far nothing is out there on this stuff. In an effort to remedy that, here's what we managed to figure out

Thomastheo op 30 sep 2017 om 17:46

2017-09-30T17:46:34Z

← Oudere versie		Versie van 30 sep 2017 17:46
Regel 7:		Regel 7:
	}}		}}

	~~== The coax itself ==~~

	One of our participants (gert) showed up with a load of old (but seemingly high quality) coaxial cable from a data center. There are other people online looking for info on the very same cable, but so far nothing is out there on this stuff. In an effort to remedy that, here's what we managed to figure out		One of our participants (gert) showed up with a load of old (but seemingly high quality) coaxial cable from a data center. There are other people online looking for info on the very same cable, but so far nothing is out there on this stuff. In an effort to remedy that, here's what we managed to figure out

Thomastheo: Created page with " {{Project |Name=Montrose coax |Picture=Montrosecoax.jpg |Omschrijving=Mystery coax specifications. |Status=Completed |Contact=thomas }} == The coax itself =..."

2017-09-30T17:46:14Z

Created page with " {{Project |Name=Montrose coax |Picture=Montrosecoax.jpg |Omschrijving=Mystery coax specifications. |Status=Completed |Contact=thomas }} == The coax itself =..."

Nieuwe pagina

{{Project
|Name=Montrose coax
|Picture=Montrosecoax.jpg
|Omschrijving=Mystery coax specifications.
|Status=Completed
|Contact=thomas
}}

== The coax itself ==

One of our participants (gert) showed up with a load of old (but seemingly high quality) coaxial cable from a data center. There are other people online looking for info on the very same cable, but so far nothing is out there on this stuff. In an effort to remedy that, here's what we managed to figure out

The cable is marked as follows:

MONTROSE / CDT 16 AWG (UL) CL2P SHIELDED COAXIAL 125C CSA CXC 60C FT4 & FT6

It's 50 ohm coax, and has a braid and foil shielding. The velocity factor is 0.85, suggesting a foam polyethylene dielectric. The exterior is supposedly UV resistant.

== Measurement ==

The velocity factor was measured with time domain reflectometry. I built a cheap and easy fast-rising-edge pulse generator after a design by Alan Wolke (W2AEW). [https://www.youtube.com/watch?v=9cP6w2odGUc See his video for details].

My version is a dip 74AC14 with all necessary components, connections and even an SMA connector soldered directly onto the chip. The 74AC14 offers six inverting schmitt triggers. The first one is used to invert an incoming signal, driving the remaining five schmitt triggers, which are ganged together and connected to the coax under test via the SMA. I'm just using a signal generator to provide the first schmitt trigger with a square wave, but you can implement Alan's solution of using the first Schmitt trigger in an oscillator with the addition of just a single resistor and capacitor.

<gallery>
File:Tdr.png|The complete circuit, all soldered onto the dip chip.
File:Tdr_risetime.png|The rising edge, on the order of a few nanoseconds.
File:Coaxreflection.png|The actual measurement, showing a round trip of 136.4ns. The actual length of the cable is 17.3m, which works out to a velocity factor of 0.85 or so.

</gallery>