I recommend download "messages.zip" from files section folder.
Then uncompress.
Then open messages-8-20-2014-thru-10-22-2019.txt (with "notepad.exe" or other simple text editor.
One line per message.
Example:
26|25|2004-09-07 22:10:24|Paul Kiciak|Re: Reflection bridge|Hi Davide, > A question, did anybody measure the directivity of the reflection > bridge described at page 21. > Thanks > 73's > iw3hev, Davide The measured directivity on my T1-6T bridge exceeds 53 dB for 0.05 - 10 MHz. Above 10 MHz, it drops at about 12 dB/octave and is 20 dB at 60 MHz. Also for reference, the measured (Short-Open) ratio in dB on my T1-6T bridge is about +0.7 dB / -0.0 dB for 0.05 - 60 MHz and about +0.3 dB / -0.0 dB for 0.1 - 30 MHz. Here is an easy way to measure bridge directivity: --- 1. Pick the desired freq sweep in TRANS. 2. Use the bridge with an OPEN on the DUT port for the cal THRU. 3. Open the Detector as usual for that cal step. 4. Put the bridge back on with 50 Ohms on the DUT port and measure it as the DUT. 5. Directivity will be essentially the negative of the measured gain, so just plot/view that. --- This test doesn't measure purely bridge directivity since it also includes the effects of source and load match in the VNA RF DDS and Detector RF Input. If desired, these effects can be reduced by inserting some attenuation (pads), say 10 dB, at the RF DDS Output and Detector RF Input. Generally, the addition of these pads would change the measured results by less than 1 dB, I expect. Obviously directivity will also depend on the quality of the 50 ohm load standard used in Step #4. The (Short-Open) ratio can be measured using the same procedure, but use the Short calibration standard in Step #4 in place of the 50 Ohm load standard. My tests were performed with the two 8 pF capacitors called for on Fig. 11 of Part 2. Other measured results with the same nominal capacitors will likely be different depending on component tolerances. Most of this is of little consequence when the bridge is used with the VNA software since the OSL calibration accounts for these and other (linear) errors The main utility of good bridge directivity is if the bridge is used in other non-VNA apllications. -- 73, Paul N2PK
Now, you can convert each symbol | to new-line, like this:
26
25
2004-09-07 22:10:24
Paul Kiciak
Re: Reflection bridge
Hi Davide, > A question, did anybody measure the directivity of the reflection > bridge described at page 21. > Thanks > 73's > iw3hev, Davide The measured directivity on my T1-6T bridge exceeds 53 dB for 0.05 - 10 MHz. Above 10 MHz, it drops at about 12 dB/octave and is 20 dB at 60 MHz. Also for reference, the measured (Short-Open) ratio in dB on my T1-6T bridge is about +0.7 dB / -0.0 dB for 0.05 - 60 MHz and about +0.3 dB / -0.0 dB for 0.1 - 30 MHz. Here is an easy way to measure bridge directivity: --- 1. Pick the desired freq sweep in TRANS. 2. Use the bridge with an OPEN on the DUT port for the cal THRU. 3. Open the Detector as usual for that cal step. 4. Put the bridge back on with 50 Ohms on the DUT port and measure it as the DUT. 5. Directivity will be essentially the negative of the measured gain, so just plot/view that. --- This test doesn't measure purely bridge directivity since it also includes the effects of source and load match in the VNA RF DDS and Detector RF Input. If desired, these effects can be reduced by inserting some attenuation (pads), say 10 dB, at the RF DDS Output and Detector RF Input. Generally, the addition of these pads would change the measured results by less than 1 dB, I expect. Obviously directivity will also depend on the quality of the 50 ohm load standard used in Step #4. The (Short-Open) ratio can be measured using the same procedure, but use the Short calibration standard in Step #4 in place of the 50 Ohm load standard. My tests were performed with the two 8 pF capacitors called for on Fig. 11 of Part 2. Other measured results with the same nominal capacitors will likely be different depending on component tolerances. Most of this is of little consequence when the bridge is used with the VNA software since the OSL calibration accounts for these and other (linear) errors The main utility of good bridge directivity is if the bridge is used in other non-VNA apllications. -- 73, Paul N2PK
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On Wednesday, October 30, 2019, 12:52:05 AM MDT, canale via Groups.Io <gf.canale@...> wrote:
Hi
I have seen in the files of the new group the messages.
I have tried to see the content but i see only a lot of figures, words
non sense.
Can anybody explain to me how to visualize correctly the
messages of the old group ?
Thanks
Gianfranco
f6itu
Juan M0WWA