Reply by Helmut Wabnig August 10, 20202020-08-10
On Mon, 10 Aug 2020 11:13:18 +0200, Helmut Wabnig <hwabnig@.- ---
-.dotat> wrote:

>On Sun, 09 Aug 2020 15:40:36 -0700, etpm@whidbey.com wrote: > >> I have been looking online but there seems to be, for a lot of the >>antennas, an assumption of prior knowledge. That I don't have. >> What I want to do is survey some of my property line. Mainly so I >>know about where it is because about 25% of the length is ambiguous. >> I can pay a surveyor to do the job but it would cost about 4 >>thousand bucks. Of course a proper survey would be more accurate and >>precise but I don't need that accuracy or precision. >> So I am looking for an antenna that could be either plugged into a >>handheld GPS or a tablet. And I don't know even where to start. I >>don't know how much gain I need. Or sensitivity. Maybe there is >>already a han held unit that is good enough all by itself. >> Our property is heavily wooded with a mix of conifers and deciduous >>trees, mostly alders. In the summer the trees make my hand held GPS >>unit useless. It is an older unit so I will be buying a modern one >>that will hopefully be better. >> I live north of Seattle and the satellites seem to be mostly in the >>southern sky, if that makes any difference to any antennas. >> I would like to keep the total expenditure for antenna and GPS unit >>to less than $400.00 >> I have looked into renting a surveyors GPS unit but have not been >>able to find anyone in the greater area who rents them. >> Can anybody help? >>Thanks, >>Eric > >Any antenna will do. > >Surveyor's antennas are better but only in conjunction with the >aprropriate equipment. >With your consumer handheld you are within 1 meter radius after >1 hour of measurement per point. Continuous averaging. > >If trees are blocking you have to measure in safe distance and then >correct the distance per yardstick measurement. Or use your feet, if >you are imperial. > >Meters are the better alternative. > >OE8UWW
Addendum: GPS measures WGS84 and this is not ident to surveyors grid. You will be off several meters. Surveyors measure combined GPS Glonass Galileo Beidoo and correct the data online via cellphone from special servers. Your private measurements are not valid, whatever you try. w.
Reply by Helmut Wabnig August 10, 20202020-08-10
On Sun, 09 Aug 2020 15:40:36 -0700, etpm@whidbey.com wrote:

> I have been looking online but there seems to be, for a lot of the >antennas, an assumption of prior knowledge. That I don't have. > What I want to do is survey some of my property line. Mainly so I >know about where it is because about 25% of the length is ambiguous. > I can pay a surveyor to do the job but it would cost about 4 >thousand bucks. Of course a proper survey would be more accurate and >precise but I don't need that accuracy or precision. > So I am looking for an antenna that could be either plugged into a >handheld GPS or a tablet. And I don't know even where to start. I >don't know how much gain I need. Or sensitivity. Maybe there is >already a han held unit that is good enough all by itself. > Our property is heavily wooded with a mix of conifers and deciduous >trees, mostly alders. In the summer the trees make my hand held GPS >unit useless. It is an older unit so I will be buying a modern one >that will hopefully be better. > I live north of Seattle and the satellites seem to be mostly in the >southern sky, if that makes any difference to any antennas. > I would like to keep the total expenditure for antenna and GPS unit >to less than $400.00 > I have looked into renting a surveyors GPS unit but have not been >able to find anyone in the greater area who rents them. > Can anybody help? >Thanks, >Eric
Any antenna will do. Surveyor's antennas are better but only in conjunction with the aprropriate equipment. With your consumer handheld you are within 1 meter radius after 1 hour of measurement per point. Continuous averaging. If trees are blocking you have to measure in safe distance and then correct the distance per yardstick measurement. Or use your feet, if you are imperial. Meters are the better alternative. OE8UWW
Reply by August 9, 20202020-08-09
   I have been looking online but there seems to be, for a lot of the
antennas, an assumption of prior knowledge. That I don't have. 
   What I want to do is survey some of my property line.  Mainly so I
know about where it is because about 25% of the length is ambiguous.  
   I can pay a surveyor to do the job but it would cost about 4
thousand bucks. Of course a proper survey would be more accurate and
precise but I don't need that accuracy or precision.
   So I am looking for an antenna that could be either plugged into a
handheld GPS or a tablet. And I don't know even where to start. I
don't know how much gain I need. Or sensitivity. Maybe there is
already a han held unit that is good enough all by itself.
  Our property is heavily wooded with a mix of conifers and deciduous
trees, mostly alders. In the summer the trees make my hand held GPS
unit useless. It is an older unit so I will be buying a modern one
that will hopefully be better.
   I live north of Seattle and the satellites seem to be mostly in the
southern sky, if that makes any difference to any antennas.
   I would like to keep the total expenditure for antenna and GPS unit
to less than $400.00
   I have looked into renting a surveyors GPS unit but have not been
able to find anyone in the greater area who rents them.
  Can anybody help?
Thanks,
Eric