Sujet : Re: Francophones
De : ianREMOVETHISjackson (at) *nospam* g3ohx.co.uk (Ian Jackson)
Groupes : sci.electronics.design sci.electronics.repairDate : 24. Dec 2024, 23:42:17
Autres entêtes
Message-ID : <DZmtQnHJjzanFwmX@brattleho.plus.com>
References : 1 2 3 4 5 6 7 8 9 10 11 12
User-Agent : Turnpike/6.07-S (<3YTqWuj$KPji+PCjvxLoeAz976>)
In message <
6ftjmjppf4421dl2ec0ek4mvfht74lmnu2@4ax.com>, Cursitor Doom <
cd@notformail.com> writes
On Mon, 23 Dec 2024 23:05:03 +0000, Ian Jackson
<ianREMOVETHISjackson@g3ohx.co.uk> wrote:
>
The real difference between the two impedances is that the amount of
PTFE dielectric in the 75 has been minimised in order to increase (with
some difficulty) the Zo from 50 to 75 ohms. IIRC, the 50 has a
more-uniform structural RLR, so it the better connector at the higher
frequencies.
>
I don't think that's quite right. The diameter of the inner and outer
conductors has more influence on Zo than the dilectric thickness.
It's right all right.
The outer diameter is the same for the 50 and 75 ohms. For the 75, I presume it's not practicable to make the pin diameter smaller and retain its robustness, so the only way to increase the Zo is to remove as much of the dielectric as possible. If you compare the 50 and the 75, you will see what I mean.
-- IanAims and ambitions are neither attainments nor achievements
Francophones
Re: Francophones