Mounting T2 on the roof of a vehicle

[Adam]

Does this not cause problems with multipath? I have read Matt Sibole's article and seen a few other photo's where the base is mounted on the roof of a car. I like the idea but have always understood that big metal objects are a problem causer. Has anyone doing this seen any problems or can maybe explain why it is not a problem?

 

[Javad]

A metal near and under the antenna does not cause problem. It makes the problem of the multipath less important when the metal object is under and close to the antenna.

 

[Matthew D. Sibole]

Does this not cause problems with multipath? I have read Matt Sibole's article and seen a few other photo's where the base is mounted on the roof of a car. I like the idea but have always understood that big metal objects are a problem causer. Has anyone doing this seen any problems or can maybe explain why it is not a problem?

I have not noticed any problems with multipath issues. Here is a picture of my T2 on my truck with my radio mast 15' in the air. I plan on getting an antenna mount for my radio also.

 

[Matt Johnson]

I have not noticed any problems with multipath issues. Here is a picture of my T2 on my truck with my radio mast 15' in the air. I plan on getting an antenna mount for my radio also.

I would be cautious with using your car battery to power your radio if that is what you doing. Using car batteries in this application and discharging them frequently will lead to the battery going bad if it is not a deep cycle battery. It might be ok if you are only outputting a few watts.

I would also suggest using a tribrach in the setup so the T2 can be leveled. It probably won't affect the position too much if it is slightly not level but it will throw off the antenna phase center variation calibration since it is based upon the antenna being level.

 

[Javad]

I would be cautious with using your car battery to power your radio if that is what you doing. Using car batteries in this application and discharging them frequently will lead to the battery going bad if it is not a deep cycle battery. It might be ok if you are only outputting a few watts.

I would also suggest using a tribrach in the setup so the T2 can be leveled. It probably won't affect the position too much if it is slightly not level but it will throw off the antenna phase center variation calibration since it is based upon the antenna being level.

I don't worry much about few degrees of T2 not being level. It does not have much effect. I worry more about parking in the soft area that car may subside few centimeters during the day, especially when it rains or ground is wet.

 

[Matt Johnson]

I agree that a few degrees won't have much of an effect. My concern is when someone may be parked on a hill.

 

[Matt Johnson]

I think a camera swivel mount work well when not parked on a level surface.

http://www.amazon.com/Professional-Mini-Ball-Camera-Mount/dp/B000L47AHG

 

[Javad]

I think a camera swivel mount work well when not parked on a level surface.

View attachment 3526
http://www.amazon.com/Professional-Mini-Ball-Camera-Mount/dp/B000L47AHG

This swivel does not hurt, but I hope no one will park in a slope! There is a big danger of some centimeters of movement!

 

[Adam]

I would be cautious with using your car battery to power your radio if that is what you doing. Using car batteries in this application and discharging them frequently will lead to the battery going bad if it is not a deep cycle battery. It might be ok if you are only outputting a few watts.

I would also suggest using a tribrach in the setup so the T2 can be leveled. It probably won't affect the position too much if it is slightly not level but it will throw off the antenna phase center variation calibration since it is based upon the antenna being level.

Got a question about using the car battery. I got the big battery pack from you guys. I have my radio and t2 mounted on my truck, I want to be able to leave the heavy battery in my toolbox locked and not have to take it in every night to charge it or bring an extension cord out to the truck. Is it possible to have the radio deep cycle battery get charged by the trucks charging system? This would eliminate all toting of the heavy battery and provide security from thieves. I don't like thieves and I am kinda lazy.

 

[Matt Johnson]

You need to use the charger that came with the battery. It controls the charging rate for proper charging. Hooking the deep cycle battery up to the truck's electrical system would cause it to charge too quickly I believe.

 

[Adam]

Can someone figure a way to do this, like maybe a new charging cord that can be connected to the vehicle battery. This would be really handy?

 

[Matt Johnson]

You could plug a power inverter into your cigarette lighter and then plug the battery charger into it but the biggest problem would be that the battery charger charges the battery at 4 A per hour. Fully discharged, it would take about 10 hours to charge the battery 40 AH battery I believe.

 

[Adam]

I want a cable that will hook to my vehicles alternator so it will charge while driving. Is this possible?

 

[Matt Johnson]

The battery has very specific charging instructions so the supplied charger must be used. It is a Power-Sonic battery. I don't see that they have DC input chargers.

 

[Adam]

The battery has very specific charging instructions so the supplied charger must be used. It is a Power-Sonic battery. I don't see that they have DC input chargers.

View attachment 3542

Thanks Matt, It seems to me that this should be doable. I mean Igot a truck with a battery already in it, why not use it. What if I just replaced my truck battery with a marine battery?

 

[Matt Johnson]

Thanks Matt, It seems to me that this should be doable. I mean Igot a truck with a battery already in it, why not use it. What if I just replaced my truck battery with a marine battery?

They are two different types of batteries, starting batteries are designed to supply a lot of power quickly for a short period of time to start the engine. Deep cycle batteries are designed to supply a low amount of power for long periods of time and last many cycles (discharges). A marine starting battery is a combination of the two but will still not last nearly the number of cycles as a deep cycle battery. Marine starting batteries I find only spec 100 cycles: http://www.interstatebatteries.com/m/product/proECL/ecl-professional. Also what happens when you discharge your battery transmitting radio signals and then don't have enough power left to start your truck?

 

[Adam]

They are two different types of batteries, starting batteries are designed to supply a lot of power quickly for a short period of time to start the engine. Deep cycle batteries are designed to supply a low amount of power for long periods of time and last many cycles (discharges). A marine starting battery is a combination of the two but will still not last nearly the number of cycles as a deep cycle battery. Marine starting batteries I find only spec 100 cycles: http://www.interstatebatteries.com/m/product/proECL/ecl-professional. Also what happens when you discharge your battery transmitting radio signals and then don't have enough power left to start your truck?

Thanks, so it looks like I need to keep charging it using the the supplied charger. It would be great if Javad could figure out how to charge their battery using the vehicle. Maybe some research and development is in order.

 

[Joe Paulin]

I have been paying attention to the method of putting the base and radio on the vehicle and while I agree it would be a time saver, I'm not crazy about driving away with my main control point at the end of the day. Maybe I'm old fashioned, but I like a control point that stays in the ground when I leave the site. Anybody else think the same way?

 

[Adam]

I have been paying attention to the method of putting the base and radio on the vehicle and while I agree it would be a time saver, I'm not crazy about driving away with my main control point at the end of the day. Maybe I'm old fashioned, but I like a control point that stays in the groundwhen I leave the site. Anybody else think the same way?

We have a real good network provided by North Carolina Geodetic Survey here, so my procedure is to locate a point using the network. Then start my base and shift to that point. So my control is on the ground and the base is only there to provide the faster corrections. I don't need it to be set up over a specific point. I use the dpos adjusted coordinates as an additional check. Another reason I like being able to leave the base and radio at the vehicle is that it's easier to secure them to a vehicle from thieves.