[amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work.

[Dave Matthews]

> On 5/24/2012 9:15 PM, Bob Bruninga wrote:
>>> all the RS rotators are 110v with no 12v option
>>> I'd hate to use an inverter just for that,
>>
>> But a 100W inverter that plugs into a cigarette lighter is only $24 or less
>> at Walmart.  That is much less than you would pay compared to trying to find
>> a 12v rotator system.



I agree.  I have built a couple of 12V satellite tracker servo systems, 
and the cost is too high in small quantities to ignore the efficacy of 
the inverter solution.

Please visit http://www.lostfrogs.com/SatTrack.htm .

My first system was in the AMSAT newsletter of July/August 2009.  That 
system worked OK, but my last system was much improved with dual 
antennas and by beefier motors and gearing, and was used to make 
numerous contacts during the 2010 Field Day.

I sold that system to a eager Satellite Ham for $400; that included hand 
made gear boxes and supported by the Parallax BASIC Stamp.  I broke even 
in materials, that is all.

My current plans are for an improved system (in terms of speeds and 
accel/decel issues) based upon the Parallax Propeller.  As a hobbyist I 
will buy what I need to put the system together, but if someone is 
interested in funding an endeavor I am open to that prospect!

Incidentally the inverter problems are maybe less than the RF into the 
servo controller problems, hence the 8' boom in the current version to 
get greater distance from the antennas and the servos.

Dave KI4PSR



On 5/24/2012 9:15 PM, Bob Bruninga wrote:
>> all the RS rotators are 110v with no 12v option
>> I'd hate to use an inverter just for that,
>
> But a 100W inverter that plugs into a cigarette lighter is only $24 or less
> at Walmart.  That is much less than you would pay compared to trying to find
> a 12v rotator system.  I had similar designs for 12v rotator systems, but
> just got lazy and realized it is easier to simply use these cheap inverters
> that are 95% efficient and just use whatever I need in the car for playing
> ham radio wether it is 12v or 115v, dosn't matter.
>
> Though watch for RFI from the inverter?
>
> Bob, Wb4APR
>
> Ted wrote:
>> Lee, there is a construction article in Chap 6 of the ARRL Satellite
>> Handbook (too complicated for me)
>>
>> But the reality is that it is easy to manually turn the RS rotor with the
>> control box from the comfort of your chair just following the azimuth
>> showing on your sat program and listening with your ear...this will get
> you
>> close enough. I have the Elk on a RS rotor with Bob's fixed elevation.
>> (Worked good enough for VUCC #226)
>>
>> Of course, the original question was about mobile installation, so unless
>> you have a long extension cord or a generator....... hi hi
>>
>> 73, Ted, K7TRK
>>
>
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