[Lex Computer & Tech Group/LCTG] Coax cable for free

[Barry Kort]

Coax for TV uses 75-Ohm cable, because that's a 4:1 transformer balun ratio
for 300-Ohm Twin Lead.  TV Antenna Twin Lead is 300-Ohms because 300 ohms
is the RF impedance of free space.  You want the transmission line to  be
impedance-matched to the antenna for maximum signal transfer.

Ethernet Computer Coax, on the other hand, is 50-Ohm.  But almost no one
uses Coax Ethernet any more because it was developed decades ago for 10
Mbps bandwidth and has long been supplanted by UTP (Unshielded Twisted
Pair) Ethernet with Modular Plugs.

On Tue, Feb 7, 2023 at 12:13 AM Charles Holbrow <chholbrow at gmail.com> wrote:

> Ted wants more information about the coax I am offering.  The long runs
> of white cable were used to connect an incoming cable signal to several
> output jacks for TV or modems in different rooms of an apartment.
> Therefore most of the cable is CATV 6 Series 18 AWG.  The connectors are
> mostly F compression.  The attached table shows the lengths, colors, and
> the specifications printed on the cables and their connectors.
>
> The splitter is a Holland GHS-2FC LI 2-way splitter 5-1000 MHz.
>
> --Charlie
>
> On Mon, Feb 6, 2023 at 12:19 PM Ted Kochanski <tedpkphd at gmail.com> wrote:
>
>> Charles,
>>
>> You need to be a bit more specific -- as the cables with different
>> impedances are totally incompatible except when used for DC or as audio
>> [shielded cables]
>> Once you are using the cables for RF OR Digital signals impedance is
>> critical
>> are you talking two of the most common: RG-58 [ 50 Ohm ] or RG-59 [ 75
>> Ohm ]
>> or something else?
>> other important parameters are: diameter, types of shields, types of
>> jackets, flexibility, fire rating, power rating, maximum operating frequency
>>
>> and then besides BNC [the most common] there are many other types of
>> connectors some of which are hard to find adapters to interconnect to more
>> standard connectors
>>
>> So your offer is interesting but incomplete
>>
>> for example see the following spec for a cable available from Pasternak
>>
>> https://www.pasternack.com/low-pim-flexible-tft-5g-402-fep-jacket-tin-outer-conductor-double-shielded-tft-5g-402-p.aspx
>>
>> Key Specifications
>> Generic Name TFT-5G-402
>> Flex Type Flexible
>> Impedance 50 Ohm
>> Dielectric Type PTFE
>> Velocity of Propagation 76 %
>> Jacket Diameter 0.16 in
>> Jacket Material FEP
>> No. of Shields 2
>> Passive Intermodulation -160 dBc
>> RF Shielding 80 dB
>> Frequency, Max 5.8 GHz
>> Max Operating Temperature 150 deg C
>> Center Conductor Type Solid
>> Inner Conductor, Number of Strands 1
>> Minimum Bend Radius, One Time 0.75 in
>> Coax Type Coax
>>
>>
>> Ted
>>
>> On Mon, Feb 6, 2023 at 11:51 AM Charles Holbrow <chholbrow at gmail.com>
>> wrote:
>>
>>> I have coax cable I would like to get rid of.  All lengths have
>>> connectors.
>>>
>>>    -  There are 4 lengths of 3' each. (3 white, 1 black)
>>>    - 36' of black
>>>    - 24' of white
>>>    - 63' 5" of white'
>>>    - 1 splitter
>>>
>>> Are there any LCTGers who would like these?  And if you want to trade, I
>>> need an ethernet to ethernet cable.
>>>
>>> --Charlie
>>>
>>>>
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-- 
The Process of Enlightenment Works In Mysterious Plays.
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