A "rubber duck" with a bnc fitting will work. Put it on one of the Vert
----- Original Message -----
From: "Ken Brown" <email@example.com>
To: <firstname.lastname@example.org>; <email@example.com>
Sent: Tuesday, November 23, 2004 11:11 PM
Subject: Re: [TenTec] Tentec Orion & Oscilloscope question
> I'd like to know the better way to take the "modulated signal" to inject
> it into an oscilloscope ?
> Someone already suggested a 30 dB 100 watt (or greater) rated
> attenuator. This is probably the best method if you only want to monitor
> while you are not actually radiating a signal. Remember though, that a
> Tektronix 453 (and most oscilloscopes) has a 1 megohm input impedance.
> If you really want an accurate voltage measurement, and an accurate 30
> dB loss through the attenuator, then the output of the attenuator needs
> to be terminated with a 50 ohm load. If you monitor the voltage at the
> output of the attenuator, across the 50 ohm load, with the 1 meg input
> of the scope, the effect of the 1 meg paralled across the 50 ohms will
> be insignificant, and the measurement will be quantitatively accurate.
> On the other hand if you are more interested in a qualitative
> measurement of your modulation waveform, without much importance
> attached to the absolute amplitude measurement, there are much cheaper
> ways to do it, that can also allow you to monitor while you are
> transmitting into an antenna (without 30 dB attenuation of your radiated
> If you were to thread a short piece of insulated wire, say about 22 AWG
> or smaller, a few inches long, inside the sheild of one of you coax
> jumpers, perhaps between you transceiver and your antenna tuner or
> antenna switch or other accessory, it could be used as a signal sampler.
> one end of the wire would connect to the shell of a BNC female connector
> and the other end to the center pin. Then a BNC to BNC cable from there
> to the o'scope input would do it.
> Have fun.
> DE N6KB
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