09-02-2019, 04:46 PM
(09-02-2019, 03:16 PM)shortcircuit Wrote: Terry said don't use inductive splitters , I thought they were all resistive.
Oh, isn't the panto season over yet?
Oh no I didn't!
The 'No' referred to your query about resistive splitters. If you re-read what I wrote, you will see that I specifically told you to use inductive splitters!
(09-02-2019, 03:16 PM)shortcircuit Wrote: On post 7 terry has put some links to ebay sellers selling splitters , are these resistive or inductive ?
If I ever post a link to a resistive splitter, feel free to have me taken out and shot!
You say your cable is double screened - do you mean two woven screens or one woven and one aluminium foil? If it is RG59 it it most likely the latter but, like RG6, it is a type. The cable type should be clearly marked or embossed on the outer sheath - tell us what it says.
Is the inner dielectric semi air-spaced or foam? If it is solid it is (a) not RG59 and (b) useless in your application. How accurate is your 6.5mm measurement? It is worthless, anyway, because a cable with two woven screens will be fatter than one with only a single one.
The only real way requires a micrometer or similar to get accurate measurements of (a) the centre conductor diameter and (b) the outside diameter of the inner dielectric. Then compare them with a range of cable specifications. Something else which it important to note is that the ratio between these two measurements determine the characteristic impedance and will be different for 50Ω & 75Ω cables or any other impedance cable.
If you can conclusively prove that it is RG59, the loss per 100m is 5.6dB @45MHz (Channel B1) and 12.3dB @ 214.75MHz (channel B13). You can use these figure to calculate the actual loss of whatever length of cable you actually use.
Comparable figures for CT100 types are 4.5dB & 9.9dB. per 100m
