XG3 and short whip as an air standard

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XG3 and short whip as an air standard

David Cutter
The XG3 has a calibrated output into a 50ohm load and can be varied over a wide range of power and frequency.  How can I use this as a standard source for field strength measurements?  

For instance, could I build passive networks to match a whip to the XG3 on each band of interest and calculate the radiation from the whip knowing its input from the network?  Since the XG3 output is variable, the loss in the networks can be adjusted to suit.  

Could I use, say a *standard* 1m copper wire whip (ie <<1wavelength on HF) to easily obtain uV/m? It could all be mounted in a biscuit tin as I once saw in a magazine many years ago.  Connecting a similar whip to the K3 with its calibrated dBm facility, I'm hoping this could all connect together in a modest home facility for experimentation and learning.  

David
G3UNA
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Re: XG3 and short whip as an air standard

Alan Bloom
One thing to keep in mind is that the XG3 has a square wave output so
there are lots of harmonics.  One consequence is you can't use it with a
directional coupler to measure SWR unless you filter out the harmonics
somehow.  Also you may need to worry about interference to other
services, although the power level is low enough that may not be an issue.

Alan N1AL


On 04/07/2017 04:03 AM, David Cutter wrote:

> The XG3 has a calibrated output into a 50ohm load and can be varied
> over a wide range of power and frequency.  How can I use this as a
> standard source for field strength measurements?
>
> For instance, could I build passive networks to match a whip to the
> XG3 on each band of interest and calculate the radiation from the
> whip knowing its input from the network?  Since the XG3 output is
> variable, the loss in the networks can be adjusted to suit.
>
> Could I use, say a *standard* 1m copper wire whip (ie <<1wavelength
> on HF) to easily obtain uV/m? It could all be mounted in a biscuit
> tin as I once saw in a magazine many years ago.  Connecting a similar
> whip to the K3 with its calibrated dBm facility, I'm hoping this
> could all connect together in a modest home facility for
> experimentation and learning.
>
> David G3UNA

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