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GPS Base Radios

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(@ridge)
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Has anyone done a field test/comparison of the current 35 Watt Satel and Pacific Crest RTK Base radio's.

It appears they are priced about the same. So how does the performance/features stack up? Less range than previous 35 watt radios due to the new transmit regs or have they overcome that someway?

What I really need is range in hills/mountains.

 
Posted : February 1, 2013 7:56 am
(@pablo)
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LR

See my post below on the Network GPS v RTK radio question.

Pablo

 
Posted : February 1, 2013 9:02 am
(@phillip-lancaster)
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Why those? Have you looked at ARwest radios www.arwestcom.com and in my opinion I think is the better choice. You get all the languages that satel and PC transmit on and then more for a cheaper price.

 
Posted : February 2, 2013 6:34 am
(@ridge)
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I looked into the ARwestcom. Its a JAVAD. For the 35 watt version the cost is about the same as the others. So if I do a test I'll try to do this one also.

 
Posted : February 3, 2013 7:07 am
(@satelguy)
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I have performed many range tests and SATEL out does both PacCrest/Trimble and Arwest/JAVAD. SATEL reaches further and has the lowest power consumption which means the battery and equipment will last longer.

While there is ABSOLUTELY NO WAY that a radio manufacturer or salesperson can ever give an accurate distance for range without a real world test in that specific location, the characteristics that determine the range are based on hard science which can be used to compare equipment before going out in the field.

I am biased for SATEL, but here are a few facts:

1. Range is calculated by taking the transmitter power in dBm (35 Watts = 45.4 dBm) adding it to the antenna gain (5 dBd) then subtracting the path loss (100 miles at 450 MHz = -125 to -130 dBm free space loss/ line of sight). The subtract the receiver sensitivity of your rover from the resulting number (-80 dBm)

• SATEL receiver sensitivity (GMSK): <-114 dBm
• PacCrest receiver sensitivity (GMSK): -110 dBm
• Arwest receiver sensitivity (GMSK): -113 dBm

All of them are capable of a 100 mile line of sight connection.

SATEL and Arwest receivers are 2x more sensitive than PacCrest (3dBm = 2x power)

2. Power consumption: besides draining a battery faster, the power consumed turns into heat as the radio operates essentially making the radio hotter. This heat can:

• Shorten the life of the equipment/ internal components
• Excess heat can degrade performance by changing the accuracy of internal calibrations.
• Satel consumes 110 Watts of power at 35 Watts Transmit
• PacCrest consumes 130 Watts of power at 35 Watts Transmit
• Arwest consumes 120 Watts of power at 35 Watts Transmit

3. Compatability: Arwest, PacCrest, and SATEL all have thier own proprietary protocols.

• SATEL has PacCrest and SATEL radio protocols
• PacCrest has SATEL and PacCrest radio protocols
• Arwest has PacCrest and Arwest radio protocols
• Having Arwest talk to SATEL is done by both radios talking PacCrest.

It is a late response, but I hope it helps.

 
Posted : February 26, 2013 1:25 pm
(@ridge)
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Thanks for the reply.

Besides driving the radio with a GPS Receiver I'd like to use a NTRIP client and an Android phone such as Samsung Galaxy III. I already have the NTRIP client and can log on and receive RTN corrections (VRS in my state) with the phone. The phone can either transmit using Bluetooth or a WiFi hotspot.

Is there a Bluetooth or Wifi adapter that can be hooked up to the RS232 on SATEL Easy Pro 35 and transmit the correction to my RTK GPS? Have you tested this?

 
Posted : February 26, 2013 8:16 pm
(@satelguy)
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It is easier to connect with Bluetooth than Wi-Fi, I have done both.

For Bluetooth, there is a UHF/Bluetooth bridge from SATEL Survey USA

Generally speaking, any serial Bluetooth adapter will work, it is more a matter of powering it. Most Bluetooth adapters are powered on pin 5 of the serial connector which has 5 VDC on a PC and some GPS. When connecting to a radio an external power connection is necessary for the Bluwtooth adapter. Once all set up, the connection is transparent.

Wi-Fi requires the incoming data to be Ethernet packets, so a serial/Ethernet adapter must be placed between the UHF radio and Wi-Fi, or Ethernet radios must be used. (both are available)

In the long term, Ethernet will be more prominent and it is already used for CORS, but there is not a lot of Ethernet radio use in the field yet for Land Survey and GNSS.

 
Posted : February 27, 2013 5:59 am