"Wes Stewart" wrote in message
...
On Tue, 5 Oct 2004 15:59:32 -0500, "John Smith"
wrote:


| If the numbers are consistant, then you can determine the directivity
| by computing the ratio between the two readings on a given port when
| the coupler is reversed.

You still need to do this.


Hi, Wes -

I read a little about directivity (a little was all I could find). Tell me
if I measured it correctly...

Forward directivity:
Normal setup, ie coupler in the usual direction (forward). Best 50 Ohm load
I could muster on the antenna (output) terminal of the coupler. Set channel
A for 0 dB. Channel B reads -29.2 dB.

Forward Open/Short characteristic:
Remove the 50 Ohm load. Set channel A for 0 dB. Channel B reads +.4 dB. Put
the HP calibrated short on the antenna terminal. Set channel A for 0 dB.
Channel B reads -1.2 dB.

Reverse directivity:
Reverse the coupler. The antenna connector now has the oscillator applied.
The BTS terminal has the 50 Ohm load. Set channel A for 0 dB. Channel B
reads -23 dB.

Reverse Open/Short characteristic:
Remove the 50 Ohm load. Set channel A for 0 dB. Channel B reads +1.1 dB. Put
the HP calibrated short on the BTS (now the output) terminal. Set channel A
for 0 dB. Channel B reads -.5 dB.

So, in the forward direction, the directivity is -29.2 dB, and in the
reverse direction, the directivity is -23 dB. Yes?

What do I do with these results? I don't know how to apply them even though
I read the HP paper.

Thanks.

John (KD5YI)

By the way, if you (or anyone else) need to contact me via email, you can
omit the kes in the address.