Hiper V vs Hiper V+10 antenna model with OPUS

I have successfully sent hundreds of static files from the Hiper-V to OPUS. Never tried the 100mm adapter with OPUS. If you are using the adapter, just apply the correction in your antenna height.

negative. this is incorrect and will produce an error of 5 cm.

I'm really glad I was barking up the right tree.

So NGS confirmed the Hiper V 100mm adapter causes the antenna phase center to be different. Which like you said, cannot be made up with just the HI measurement alone...if you are using the adapter you have to select that antenna configuration in OPUS.

Did you say you were going to run a static at 2m Hiper V and a static with the Hiper V +10cm adapter on the same point as a proof of concept?

Causes the phase center to be different??ÿ I'm sorry, this doesn't make any sense to me, it seems that it would make it exactly 10cm higher.?ÿ You are still suppose to measure to the bottom of the mount.?ÿ The entire thing doesn't make sense to me but maybe I'm missing something obvious.?ÿ I've never used the little 10cm pole so its a moot point to me I guess.

I was at a loss as well.

Fact-

2.100 m input height using 2.000 m tripod, the .100 m adapter and the hyper_v model will produce a solution 0.052 m different than-

2.000 m input height using 2.000 m tripod, the .100 m adapter and the hyper_v+10 model.

I thought a ground plane type antenna would negate anything happening under the antenna but that is NOT the case.

NGS has checked their models and believe them to be correct. "I tested the calibrations in OPUS using two sets of the original test data, which had been collected both with and without the standoff [.100 m adapter].  When processing data collected with the standoff in place, I used TPSHIPER_V+10 with a zero (in my case) antenna height [concrete pier].  Conversely, when using data without the standoff, TPSHIPER_V was chosen, again with a zero antenna height."

They attribute this difference to near-field multipath. see attached file.

How do you mount the antenna on a tripod with the rtk radio attached, and NOT use the .100 adapter??

If the 10 cm adapter has that much effect on this antenna, how much variation are we getting with other antenna models as they are mounted on a metal tripod vs fiberglass tripod vs fiberglass pole vs metal pole?

Makes me glad I used the old ground plane antenna 14532.00 for all my GPSonBM submissions.?ÿ That should be less susceptible to what is underneath.

I have a question into NGS asking for which model they recommend for a 2m carbon fiber rod.  No response yet.

The assumption that the two antennas are the same seems incorrect given that they have different part numbers. Why would a different part number be assigned to a unit that only differed by a 10-cm rod?

Attached are the graphics associated with the antenna phase model. While externally they look identical, the internals probably do not. I also attach an extract from an old OPUS static extended solution showing exactly how the tool determines antenna height wrt phase centers.

FWIW: On a related matter, years ago there was a problem due to an antenna manufacturerƒ??s attempt to fix a problem with their unit. It involved a physical change to the antennaƒ??s internals. It was impossible to determine which of the models had the change by external examination. The only way to tell which units had the change was to do so via the serial number. In this case the manufacturerƒ??s ?ÿmodel number was not changed to reflect the modification.?ÿ

I think the whole difference in the phase center is that the adapter is not under the antenna...it's right beside it. Wasn't the Hiper V the first Topcon GPS to have the antenna mounted on the bottom of the unit? I always assumed so that they wouldn't break as much as when they were mounted on the top like the Hiper Lite or GA. Below is a picture of the Hiper V antenna:

https://www.benchmarksupply.com/topcon-hiper-v.html

Also, the ref measurement is to the bottom of the adapter and not the bottom of the mount??? Was that diagram taken from NGS as well GeeOddMike? Are the part numbers because there are some Hiper Vs that did not have the bottom antenna mount?

From the antenna calibrations link on the NGS home page choose browse by manufacturer.

The antenna drawings are from this page. The ƒ??spacerƒ? appears centered not offset.

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I think one thing that is confusing is the mark they have labled SHMM.?ÿ There is a little ledge on the side and it stands for Slant Height Measure Mark.?ÿ We own an earlier version of the Hiper V called a Hiper II.?ÿ They look identical.?ÿ I am assuming that adding the little pole changes the phase center somehow, but I still don't see how.

I use a 1' extension when setting up on top of a tripod, I have no clue how that affects anything but so far I don't have problems.?ÿ Like someone above noted, there are so many different poles and different ways to setup a GPS unit how can you predict how that would change the phase center.

I am doing a 4 hour session on our local GPS on BM station today, using 2.000 m +.100 m with our other receivers (hiper II) to compare the results.?ÿ

so HIPER V + 10?ÿ + NONE for this one

and HIPER V + NONE for this one

??

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@standing-on-the-corner What was your results?

@aaron-k-burns Sorry for the delayed reply.  As of now, my testing results are inconclusive.

I have a current project, where we are running 4 types of receivers and digital levels.  A few more weeks and I may know something.