Monthly Archives: January 2014

Respirator Required to Walk to Work in Salt Lake City

I just purchased one of these:

Image

so that I can safely walk to work in Salt Lake City. Really!

The air quality in Salt Lake City is so bad, on so many days that it is no longer safe to walk, bike or exercise outdoors. Most days, we have the worst air in the nation, only 2nd to the air quality in Logan Utah. Every polluted day (basically every day in the Winter) is just like smoking a pack and a 1/2 of cigarettes. I am not kidding.

The Utah government has some 1/2 baked plans that might result in better air 20 years from now. But it is the pie in the sky stuff that is clearly just what it appears to be. Bullshit.

What we really need to do is STOP enticing new companies to move to the Wasatch Front, bringing more people and more pollution. The solution is NOT more business. The solution is NOT more people.

The state should STOP stealing money from the the existing companies to pay open BRIBES to prospective ‘move in’ companies. The BRIBE money should instead be paid to move the companies that are already here elsewhere so their employees will be safe.

Sundance, Outdoor Retailer are great forums to get the word out: Salt Lake City is just a HORRIBLE place to live, work and play. It is NOT safe to breath the air here. The Wasatch Front has become a wasteland of  unsustainable growth and dysfunctional government. Becker’s response will be to write more parking tickets, perhaps reducing the permissible maximum tire to curb spacing  to 12″. Now that will clear up the air!

If you are a company, planning to move a business to Salt Lake City/Provo/Logan, please think twice about it! You are moving to an unsafe environment. You are putting the health of your employees and their children at grave risk. You very seriously need to rethink your plans and consider ANYWHERE but Salt Lake City as a destination for your company. Salt Lake City is horrific wasteland. You should go elsewhere, someplace safe.

Assuming you like breathing…

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Horrible SV Constellation, Even with GLONASS

I bet you think that just because you have GLONASS you will ALWAYS be able to survey.

Not so fast! Check out this constellation from Salt Lake City at 1:35 pm 22 Jan 2014:

Image

Yes, that is 3 US SV’s above 30 degrees and
4 GLONASS SV’s above 30 degrees.

Surprisingly the HDOP = 0.68, VDOP = 1.38 and GDOP 1.93. Without tracking GLONASS, I don’t know how much RTK work we could get done right now.

I guess the take-away is “Don’t think you never need to mission plan, even if you have GLONASS. I can’t fix in the parking lot with a 2-meter pole, but with a 15′ pole:

Image

B.I.N.G.O.!

 

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What to do for Absolute Antenna Calibrations, when there are not any?

I could write a book on the difference between relative and absolute antenna calibrations, but I don’t need to and you should not spend much time wondering about why. Or if. You ‘Just need to make the change to Absolute Antenna Calibrations’ for everything.

But, depending upon which antennas you own, you may find there is not an absolute calibration for your antenna! What to do?

First a little background. Let’s look at a couple of sample antenna:

Relative ASH111660       NONE L1 GPS/GLONASS, base of RF connector->N  NGS (  3) 10/06/02
       0.3      -0.7      75.4
Absolute ASH111660       NONE L1 GPS/GLONASS, base of RF connector->N  NGS (  3) 10/06/02
       0.9      -1.1      57.3
The Absolute calibration is -18.1 mm from the relative calibration.
Relative MAG105645       NONE L1/L2 GPS                                NGS (  2) 00/12/21
       0.6       3.6      65.6                              
Absolute MAG105645       NONE L1/L2 GPS                                NGS (  2) 00/12/21
       1.2       3.2      47.5
The Absolute calibration is -18.1 mm from the relative calibration.                   

In general, this trend continues for most antenna because they were NOT actually re-calibrated for absolute calibrations, the absolute values are 18.1 mm less than the relative values. This is because this is the difference between the reference AOAD/M_B Dorne Margolin B Chokering:

Relative AOAD/M_B        NONE Dorne Margolin B, chokerings (Rogue)     NGS (  0) 97/10/27
       0.0       0.0      78.0                              
   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0
   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0
       0.0       0.0      96.0                              
   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0
   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0
Absolute AOAD/M_B        NONE Dorne Margolin with chokerings (Rogue, A IGS (  0) 11/03/25
       0.6      -0.4      59.8                              
   0.0  -0.2  -0.9  -1.9  -3.2  -4.6  -6.0  -7.1  -7.9  -8.2
  -8.1  -7.4  -6.2  -4.6  -2.3   0.7   4.5   9.1  14.2
      -0.1      -0.6      88.3                              
   0.0  -0.1  -0.5  -1.1  -1.8  -2.6  -3.4  -4.2  -4.8  -5.2
  -5.3  -4.9  -4.0  -2.8  -1.3   0.5   2.8   5.7   9.4

The L1 difference (59.8 – 78.0) = -18.2 mm (sorry, I don’t know why it is 18.2 instead of 18.1)
The L2 difference (88.3 – 96.0) = -7.7 mm

So if you have an antenna like the NAP 100 with a relative calibration north : 1.0mm, east : 3.8mm, up : 73.2mm above ARP; which would look like this:

Relative MAGNAP100         NONE L1    GPS
       1.0     3.8      73.2

I believe it is safe to say the absolute calibration would be:

Absolute MAGNAP100         NONE L1    GPS
       1.0     3.8      55.1

By the way, if you are still using L1 only receivers to do static work (I will forgive you if you are running Stop and Go) you need to sell them (PM2, PM3) on ebay and trade-up to X90-OPUS receivers. The days of L1 only should be numbered!

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What happens when you shoot a ZMax with a shotgun?

A aerial photography was using this receiver for ground control. They left it on a panel, when they came back they noticed a pickup passed them quickly.

The receiver was still blinking:
Thales Zmax Reciever Damage 002
Thales Zmax Reciever Damage 006

We replaced the GSM module and the receiver fired right back up

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Do Birds on CORS Antennas Matter?

Hmm

Bird1

 

Bird2

 

I think if the bird is wider than the antenna, then yes.

In this case, when the bird is on the base antenna, all rovers experience huge Z offsets. Whood a thunk?

 

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Nuts for Antenna Connector on [ PM3, MMCE, MMCX, MM100, MM120, PM100, PM120, PM200, PM220 ]

I lost the antenna connector nut on my (pick one: PM3, MMCE, MMCX, MM100, MM120, PM100, PM120, PM200, PM220) GPS Receiver!

The antenna nut is critical piece of the receiver. Without it, the connector will push into the body. The body will not be watertight. You won’t be able to use your device.

Below, I have links to where you can purchase the nuts for about $2 each.

Here is some background information and pictures:

1The connector on a PM100, with .LC style nut shown

2What the nut screws on

3How this fits into a receiver body (MMCX in this case)

The connector is a Lemo connector part number EPE.00.250.NTN. You can find the connector on the top of page 18 in the [ LEMO_CATALOG_47-00262-001 ].
The nut is shown on page 30 of the same [ LEMO_CATALOG_47-00262-001 ].
The nut is a M7 (7 mm) by 1/2 mm thread, panel nut. It is doubtful that you can purchase this nut from a secondary source (I checked all the nut and bolt shops here in SLC with no success.)
The part description is “GEC Conical nut” and the part number is shown as GEC.00.240.LN:
4
I believe the part number is printed incorrectly in the catalog and should actually be: GEC.00.240.LC.
You can purchase this nut directly from Mouser: [ GEC.00.240.LC ]
If conical nuts are out of stock, consider purchasing the hex nut version from Mouser: [ GEC.00.240.LN ]:
6
or the notched version [ GEG.00.240.LC ]:
7
they will set you back about $2.00 each.

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Exactly How Do I Get a FCC License for My RTK Radio?

Holy cow!

That [ Pirate article ] has only been out for two days and I am getting slammed by upset people.

Based on comments, I need to fully answer a couple of recurring questions. This is the first of the questions:

Exactly How Do I Get a FCC License for My RTK Radio?

I have used several licensing companies over the years. My current suggestion (I don’t have a horse in the race) is [ Business Radio Licensing ] in Laguna Niguel California. I am positive that there is licensing company in your neighborhood who will do you a good turn also. There are also a few who will screw you. [ This ] (A+) is why I initially choose BRL.

Go to this web address: [ New License ]  and fill out the questions. Here is help for the questions:

3. Frequency Requested: “Standard RTK GPS Pool”, Monitor: NO

4.  Band: 451-469; Splits: leave blank

5. Conventional.

6. Base and Mobile Simplex FB.MO.

7. Wattage: 35 watts in Mobile box.

8. Bandwidth 12.5 KHz

9. No

10. Digital Data

12. Location: list your state, or the states you work in, if you work everywhere then USA.

13: Other: Tripod, height above ground 20 feet.

16: In additional comments: ‘Request Temp License During Processing”, and list the emission designators from this table for all of the radios you will be using:

FCC IDs and Emission Designators for Pacific Crest Radios

   

Emission Designators

Model FCC ID Number

@12.5 kHz

@25 kHz

PDL HPB KEAPDL4535

9K80F1D

19K6F1D

PDL LPB KEAPDL4520225

8K60F1D

17K8F1D

EDL II KEAPDL4520225

8K60F1D

17K8F1D

Sitecom KEAPDL4520225

8K60F1D

17K8F1D

ADL Vantage Pro KEAADLP

9K75F1D

19K6F1D

ADL Vantage KEAADLV

9K75F1D

19K6F1D

ADL Sentry KEAADLS

9K75F1D

19K6F1D

ADL SLR3 KEAADLF

9K75F1D

19K6F1D

XDL Micro KEAXDLM

7K90F1D (403-430MHz) 8K34F1D (430-473MHz)

14K5F1D

FCC IDs and Emission Designators for Trimble Radios

   

Emission Designators

Model FCC ID Number

@12.5 kHz

@25 kHz

HPB450 KEAPDL4535

9K80F1D

19K6F1D

PDL450 KEAPDL4520225

8K60F1D

17K8F1D

PDL450 Fixed KEAPDL4520225

8K60F1D

17K8F1D

TNL450i, 410-430 KEATNL450I

9K75F1D

19K0F1D

TNL450i, 430-450 KEATNL450I

9K75F1D

19K6F1D

TNL450i, 450-470 KEATNL450I

9K75F1D

19K6F1D

TNL450i, 410-470 E5MDS-TRM450

11K3G1D

20KG1D

TDL 450H KEAADLP

9K75F1D

19K6F1D

TDL 450L KEAADLV

9K75F1D

19K6F1D

TDL 450i KEAXDLM

7K90F1D (403-430MHz) 8K34F1D (430-473MHz)

14K5F1D

Be forewarned that requesting a 25 KHz designation may cause delays or problems.

The most common dessignator is 9K75F1D.

Good luck and clear sailing.

Mark

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