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TR503A VNA Sweep Speed

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wa2pux
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Joined: February 16th, 2020, 12:57 pm
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TR503A VNA Sweep Speed

Post by wa2pux » October 5th, 2020, 8:07 am

FIRST - there are no posts and no way to add posts to the TR500 Series VNA forums.
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I use my TR503A VNA to tune duplexers (among other things).
I set the Start and Stop frequencies to match the relatively narrow band I need (1MHz).
I calibrate (full two port calibration) the instrument once set up.
I have to wait ~5 seconds between screen updates.
When tuning a duplexer, this is a LONG time to have to wait to see the results of the adjustment you just made.
Is there any possible way to speed this up?

For what I paid for this thing, I expected a significantly faster response.

w2aew
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Re: TR503A VNA Sweep Speed

Post by w2aew » October 5th, 2020, 9:19 am

I just posted a "test post" in the VNA Forum area, so it looks like it is working (for me at least).

Regarding your sweep speed question - can you provide details for a given sweep (start/stop or center/span, number of points, IF BW setting, etc.)?

Also, what version of VectorVu-PC are you running? (there was a speed improvement made with later versions) The latest version (v2.0.1) can be found here: https://www.tek.com/spectrum-analyzer/t ... idate-v201
This version defaults to Fast Sweep Mode (as opposed to Normal - found at Sweep Setup > More > Sweep Mode).

Note that due to the design of the unit, sweep speed at HF/VHF is slower than UHF and above.

Example sweep times with v2.0.1:
145MHz center freq, 5MHz span - 4.8s Normal mode, 0.285s Fast mode
450MHz center freq, 5MHz span - 0.230s Normal, 0.072s Fast mode

wa2pux
Posts: 5
Joined: February 16th, 2020, 12:57 pm
Country: United States

Re: TR503A VNA Sweep Speed

Post by wa2pux » October 5th, 2020, 10:44 am

Just updated my VectorVu from 1.0.3 to the 2.0.1 as suggested.
WOW! WAY faster! Very nice. Not as fast as my very, very, VERY OLD HP 8753A, but a GREAT improvement!

Two other questions...please..
1. If I do my cal at let's say 400 to 500 MHz and then specify a new , much narrower span to better see the reject of a duplexer (e.g. START: 442 STOP:443MHz), will the cal still be valid as long as it is a subset of the original span at which it was calibrated? I am thinking yes, but want to be sure.

2. How long does a typical TTR500 series take to give the "I'm warm enough" flag?
Mine seems to take a VERY long time to tell me that (never timed it, but it HAS to be in excess of 1/2 hour).

w2aew
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Re: TR503A VNA Sweep Speed

Post by w2aew » October 5th, 2020, 11:01 am

For your other questions:
1) Your calibration will still be valid, but keep in mind that the unit will interpolate the correction values between your original calibrated points. For your use case, spanning in to get a closer look at a band-reject notch, it should fine.
2) I believe that the temperature indicator is reading an actual internal temperature sensor, and as such, the warm-up time will depend on the environment. In my relatively warm office, it is typically only 10-15 minutes. I believe the "official" warm-up time is 30 minutes, but you certainly will get a good reading of notch position much sooner than that.

73 de W2AEW

wa2pux
Posts: 5
Joined: February 16th, 2020, 12:57 pm
Country: United States

Re: TR503A VNA Sweep Speed

Post by wa2pux » October 5th, 2020, 11:05 am

PERFECT! Thank you for your help! :D

BTW, EVERYTHING seems to happen faster with the new software. MUCH more responsive interface and calibrations and everything.

I am a happy camper now.
:D :D :D :D :D :D :D :D

w2aew
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Posts: 145
Joined: December 2nd, 2008, 2:27 pm
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Re: TR503A VNA Sweep Speed

Post by w2aew » October 5th, 2020, 11:20 am

Happy to be of help!

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