Re: [TowerTalk] [Bulk] 80 mts four square or yagi?

[Pete Smith N4ZR <n4zr@contesting.com>]

I believe that the data used are somewhat higher-resolution\for 
locations within the United States, compared to the Shuttle Radar 
Terrain mission data available for the rest of the world, though this 
gap is being closed currently, so that all available data will be 1 
arc-second (30 meters) lateral resolution. Still, unless you live in 
really broken terrain, they should be quite comparable.  Do they seem 
more similar on lower frequency bands?
See <https://lta.cr.usgs.gov/SRTM1Arc> for a good discussion of what is 
available.
73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.

On 3/10/2015 9:44 AM, Jorge Diez - CX6VM wrote:
> There´s a great difference from K6TU terrain files and files you can made
> from Google Earth :-)
>
> At least to my location
>
> 73,
> Jorge
>
>
> -----Mensaje original-----
> De: TowerTalk [mailto:towertalk-bounces@contesting.com] En nombre de Pete
> Smith N4ZR
> Enviado el: lunes, 09 de marzo de 2015 12:56 p.m.
> Para: towertalk@contesting.com
> Asunto: Re: [TowerTalk] [Bulk] 80 mts four square or yagi?
>
> A lot depends on what angles you need, from where you are.  HFTA's Figure of
> Merit can be useful here. K6TU.net now offers free online terrain profiling
> for both US and non-US locations, the latter using SRTM data.
>
> 73, Pete N4ZR
> Check out the Reverse Beacon Network at
> http://reversebeacon.net,
> blog at reversebeacon.blogspot.com.
> For spots, please go to your favorite
> ARC V6 or VE7CC DX cluster node.
>
> On 3/8/2015 5:39 PM, Grant Saviers wrote:
> > Any comparison has to be gain vs elevation angle.  In my modeling 80m
> > yagis & dipoles don't have sufficient low angle gain until they are up
> > about 150'.
> >
> > A 2L 80m yagi at 150' models its gain peak as about 12dbi at 25deg and
> > 3dbi at 5deg elevation.
> >
> > A 4sq over salt water yields about 9dbi from horizon to 25deg
> > elevation.  Obviously, best case, so modeling is needed for every
> > design of radials and ground properties.
> >
> > Both are a significant investment so should be carefully modeled.
> >
> > Grant KZ1W
> >
> >
> > On 3/8/2015 10:06 AM, Jorge Diez CX6VM wrote:
> > > Hello
> > >
> > > Wish someone have some analysis or field test to compare a 4SQ with
> > > sixty 1/4 WL radials each vertical and a 3 element wire yagi with
> > > boom at 115ft
> > >
> > > Which one have more GAIN?
> > >
> > > Thanks
> > > Jorge
> > > CX6VM/CW5W
> > >
> > > Enviado desde mi iPhone
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