Measuring SMA relays at UHF
Hi all!
Playing with my toys, trying to create a CP 10x2 UHF antenna
Using an Anritsu S113b which does not have direct voltmeter readout. These numbers were calculated by making a return loss measurement and converting it to relative phase with their Line sweep tools software.
Converted data here:https://www.flickr.com/photos/n3ykf/
I have a Times T-100, using a similar procedure, very similar, almost identical numbers were returned.
Setup: S113b has an N female. To make SMA, I added an N male to male, then a N female to SMA female.
Used a calibrated SMA OSL kit.
Test pieces: two Transco SMA 24V relays and an SMA jumper, consisting of two elbows and some straight pieces.
Coax to be used in final device is RG-142B/U. (El Cheapo on the bay)
Did use a 5/16 wrench to snug up all the connections.
First order of business was to calibrate all the test gear. Noting how long the adapters attached to the N connector were as well as noting the length of the test cable.
Got some interesting results:
RYA NC: 232.2 degrees
RYA NO 231.8 """"""
RYB NC 231.3""""""""""
RYB NO 231.0 """"""""""
SMA jumper to connect Common->NC to NC->common 281.3 degrees.
Does this look correct? How does such a small package contain such a lengthy RF path?
I went through this whole process (took about 5 times longer) prior to my trip to 5J0 and realized that mistakes had been made. Skipped the CP attempt, Took the pair of crossed linear 10 elements, diddled by a Tohtsu spdt 12v instead Worked like a charm from AOS to 5-7 degrees above the horizon so that I could switch polarities. What a blast. Used my homebrew rotator.
https://www.youtube.com/watch?v=1sDP6lAiWGw
Please ignore my 2yo little monsters. They can and do make s9+ noise.
Trying to get the coax for a cp antenna correct this time. Waste no more coax..
Currently in the field. I'm wondering if there's something inside the relays making them look longer. Coax seems to be realistic lengthwise. SMA jumper is maybe 6cm long. Measures slightly longer than 3/4 Lambda, though.... Will make some measurements to a test article, disassembly and photos. Stand by, pussycat!!
Norm n3ykf
Forgot to mention:
The procedure to recover real "length" of what you're trying to measure is arcane. Due to it's zanity, I thought I'd post it.
Imaging a number line where you're located at Zero.
Ahead in a positive manner proceeds zero to +180. At +180, it changes to -180 and decreases to 0. Thus completing 360 (two pi, whatever) of datum.
When a negative number is seen reported by the coverted return loss data, to get an actual length, the reader must determine how many degrees it's passed +180. Add or subtract, depends on how you'd like to play with the signs.
Then add that number to +180, assuming less than one cycle.
More than one cycle, add N times 2pi plus pi.
In human speak:Nx360+180+your result.
Given that number, start subtracting. Lets use an example from the data I just posted.
Ex: https://www.flickr.com/photos/n3ykf/30182713518/in/dateposted/
Start with -97 (Marker 2, 436.8 MHz) and work your way back: 281.3 degrees.
NOWHERE is the procedure detailed. I found the clues over in the programming manual.
What a way to spend a day.
Norm n3ykf On Wed, Aug 15, 2018 at 10:47 AM Norm n3ykf normanlizeth@gmail.com wrote:
Hi all!
Playing with my toys, trying to create a CP 10x2 UHF antenna
Using an Anritsu S113b which does not have direct voltmeter readout. These numbers were calculated by making a return loss measurement and converting it to relative phase with their Line sweep tools software.
Converted data here:https://www.flickr.com/photos/n3ykf/
I have a Times T-100, using a similar procedure, very similar, almost identical numbers were returned.
Setup: S113b has an N female. To make SMA, I added an N male to male, then a N female to SMA female.
Used a calibrated SMA OSL kit.
Test pieces: two Transco SMA 24V relays and an SMA jumper, consisting of two elbows and some straight pieces.
Coax to be used in final device is RG-142B/U. (El Cheapo on the bay)
Did use a 5/16 wrench to snug up all the connections.
First order of business was to calibrate all the test gear. Noting how long the adapters attached to the N connector were as well as noting the length of the test cable.
Got some interesting results:
RYA NC: 232.2 degrees
RYA NO 231.8 """"""
RYB NC 231.3""""""""""
RYB NO 231.0 """"""""""
SMA jumper to connect Common->NC to NC->common 281.3 degrees.
Does this look correct? How does such a small package contain such a lengthy RF path?
I went through this whole process (took about 5 times longer) prior to my trip to 5J0 and realized that mistakes had been made. Skipped the CP attempt, Took the pair of crossed linear 10 elements, diddled by a Tohtsu spdt 12v instead Worked like a charm from AOS to 5-7 degrees above the horizon so that I could switch polarities. What a blast. Used my homebrew rotator.
https://www.youtube.com/watch?v=1sDP6lAiWGw
Please ignore my 2yo little monsters. They can and do make s9+ noise.
Trying to get the coax for a cp antenna correct this time. Waste no more coax..
Currently in the field. I'm wondering if there's something inside the relays making them look longer. Coax seems to be realistic lengthwise. SMA jumper is maybe 6cm long. Measures slightly longer than 3/4 Lambda, though.... Will make some measurements to a test article, disassembly and photos. Stand by, pussycat!!
Norm n3ykf
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Norm n3ykf