Sujet : Re: Francophones
De : ianREMOVETHISjackson (at) *nospam* g3ohx.co.uk (Ian Jackson)
Groupes : sci.electronics.design sci.electronics.repairDate : 23. Dec 2024, 16:22:24
Autres entêtes
Message-ID : <Oi4e+cFwAYanFw0d@brattleho.plus.com>
References : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
User-Agent : Turnpike/6.07-S (<XlTqWap7KPDWaPCjsRGoeAF+yl>)
In message <
vka5ni$r5r3$1@dont-email.me>, piglet <
erichpwagner@hotmail.com> writes
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
Cursitor Doom <cd@notformail.com> wrote:
>
On 21 Dec 2024 22:30:23 GMT, Allodoxaphobia <trepidation@example.net>
wrote:
>
On Sat, 21 Dec 2024 21:37:59 +0000, Cursitor Doom wrote:
in series with your 50 Ohm source.
>
Yes, but you know what a *bitch* it is to find a purely resistive 10
ohms....
>
Maybe just a length of nichrome wire?
>
Still got parasitics. Avoiding them is a craft in itself.
>
I wouldn't worry about the inductance of an ordianry 1/4 -Watt resistor
at the frequencies involved. The only point where it might make any
difference is the VHF input and oscillator tuning - and I can't think
you need a great level of accuracy to align a domestic portable radio.
>
It is even possible that they specified a 60-ohm sig gen because they
knew that most of the available ones would be near enough at either 50
or 75 0hms. Another possibility would be to try to make you think you
had to return the radio to their specialised service department for
repair. The avarage radio shop (if there are any left) simply wouldn't
care and would use whatever they had on the shelf above the workbench.
>
60 ohms was a popular impedance for RF test gear in Europe in the 1950s and
60s
>
For many purposes you can ignore the difference between the 50 and 75 ohm impedances (and 60 if you ever come across any). However, be very aware only BNC 50 and 75 ohm connectors are mutually mechanically mateable (yes - they really are!). I don't know if any others that are.
-- IanAims and ambitions are neither attainments nor achievements