Hi Eddie,
"Antiparallel" is the description i normally use and i most often heard for such arrangements. :-)
73, Stefan
________________________________
Von:
[email protected] im Auftrag von g3zjo
Gesendet: Mo 14.06.2010 10:33
An:
[email protected]Betreff: LF: RE: RE: Static protection when using a soundcard as an Rx
Hi All
I think I will add a 600ohm 1:1 transformer to my sound card LF set up in addition to the diodes I have at present.
Incidentally it has suddenly struck me what a loose term 'back to back' diodes is. It could be confusing for an
enquirer. What is being referred to here is 2 diodes in parallel across the input, one of them one connected one way round and one the other.
Back to back diodes is also a term for two diodes in series connected + to + or - to -, putting the open ends of this combination across the input would do nothing to protect the circuit. Joining the open ends and placing that across the input would not be right either.
Eddie G3ZJO
-----Original Message-----
From: Stefan Schäfer [mailto:
[email protected]] On Behalf Of Stefan Schäfer
Sent: 13 June 2010 23:54
To:
[email protected]Subject: AW: RE: Static
protection when using a soundcard as an Rx
Hi Brian and also welcome :-)
I would combinate back to back diodes with a isolating transformer for audio. A combination of the hints you heared before ;-) The transformer prevents galvanic coupling (could become a problem even if your wire is grounded for high voltages by the diodes) and the diodes on the soundcard side are an additional safety factor that reduces voltage spikes. But the diodes start to conduct already at some 1/10 volts (depending on the temperature) so you may use 2 in series each...
73 es gl becoming QRV!!
Stefan/DK7FC
________________________________
Von:
[email protected] im Auftrag von James Cowburn
Gesendet: So 13.06.2010 20:09
An:
[email protected]Betreff: LF: RE: Static protection when using a soundcard as an Rx
Hi Brian
Welcome to the reflector. Back to back diodes are good option to limit surges and spikes, but others are more qualified than me to advise
With best regards
Jim
Dr. James Cowburn G7NKS
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From:
[email protected] [mailto:
[email protected]] On Behalf Of Brian Reay
Sent: 13 June 2010 17:38
To:
[email protected]Subject: LF: Static protection when using a soundcard as an Rx
Hi All,
My first post to the reflector.
I plan to try using a sound card and a "long wire" (well as long as I can fit into the garden) antenna and later a kit lofted antenna but I'm concerned re static.
Normally I'd add a "dc short" with an inductor but at 10kHz than is a big inductor. A resistor is another options.
Does anyone have any other suggestions, please.
73
Brian
