Capacitor/Condenser Microphones

In Netscape - which I still prefer to browse ngs. Click on 'cancel message'

Graham

Indeed !

You need to be quick about it.

Some news servers don't allow message cancelling anyway. Google for example IIRC.

Graham

think cancellation got abused too much.

NT

You know, every time I build a VHF oscillator I end up with so much in the way of microphonics that I wish someone had hired me to build a microphone instead :-)

Tim.

Amen! But then I guess it's because I don't use silver plated copper chassis, with shock mounted caps and feedthrus all over the place.

Am Sat, 6 Nov 2004 22:50:02 -0800 schrieb Watson A.Name - "Watt Sun, the Dark Remover" :

Even in the 80ties you could buy Electret-mics with a diameter of 5mm and

oscillation?

up

Sennheiser makes them; the MKH series is an FM mike. It's the same scheme that was used in the Weathers phonograph pickup many long years ago.

Norm Strong

Am 7 Nov 2004 07:18:36 -0800 schrieb Tim Shoppa :

I know this the other way round: every time I try to build an RF Amplifier, its has much more stable VHF,UHF or even GHz oszillation than if I had to build an oscillator. :-)

Well, it _did_ disappear off _my_ server.

And it's been archived at google already, so I guess "cancel" is kinda moot.

Cheers! Rich

Hi Graham,

I use Mozilla because it doesn't freeze up on me. Although it is closely related to Netscape it does not have a cancel feature. When I searched the help routine for it, it also came up with a blank.

Regards, Joerg

Hi Richard,

That is what I thought. Once it propagated it seems to be too late. Not that I ever wanted to cancel a post but thanks to all you guys for explaining. I simply did not know that one can do that.

Now I just have to find out why sometimes a post never shows up. Or even more weird, if a question is posted in two NGs my answer shows up in one but not in the other eventhough both NGs were in the adressee list before sending.

Regards, Joerg

Sods Law: Oscillators dont, amplifiers do

Cheers Terry

"Joerg" wrote

It happened to me just last week. A post of mine never showed up on Supernews, but responses to it did. And the post showed up on our NNTP server at the office and on the Google archive.

NNTP (Usenet newsgroups) is *not* a guaranteed messaging protocol like SNMP (email). It is a best-effort, store-&-forward, peer-to-peer mechanism and likely works better now with The Internet as a transport infrastructure than it did back in the early days of DARPAnet, etc.

I used an MKH816-TU3 once. IIRC, it had an 8MHz oscillator and used a

1. No noise due to DC leakage in transducer.
2. Better linearity, which can be a problem with DC bias if the change in voltage is a significant fraction of the bias voltage. This normally isn't a problem with 48V bias, but might be a problem at high SPL with a lower voltage bias.

Regards, Allan

closely

Under Message, the Delete message is grayed out. Have you tried that?

oscillation?

in

I thought that was Barkhausen..

Anyway, that's been my experience, also.

Schematics:

Regards, Allan

From

"RF Condenser Microphone A very special way to convert the continuous change of capacitance in a condenser microphone into a usable electric signal. Here the microphone capsule is part of the frequency controlling circuit of an RF oscillator. The change of capacitance modulates the RF in its frequency and the output of the first stage is an FM signal as you have in any radio. (RF is about 8 MHz, but it is carefully shielded - no chance to listen to someone else's mics). The second stage is just an FM demodulator. The big advantage is that the capsule impedance is approx. 300 Ohms so there won't be any problems using such a condenser mic in a very moist environment. The big disadvantage is the large amount of electronics and the requirement to shield the RF carefully. RF mics are built by Sennheiser (MKH series)."

The schematic looks more like fixed frequency drive to me though.

Regards, Allan

Which schematic?

In the one at

Cheers! Rich