[mythtv-users] Automatic antenna aiming?

Don Brett dlbrett at zoominternet.net
Mon Dec 2 03:30:54 UTC 2013


On 12/1/2013 3:12 AM, Karl Dietz wrote:
> On 01.12.2013 05:44, Monkey Pet wrote:
>> On Sat, Nov 30, 2013 at 9:15 AM, Don Brett <dlbrett at zoominternet.net
>> <mailto:dlbrett at zoominternet.net>> wrote:
>>
>>     Does anyone know if there's a way  to automatically aim an antenna
>>     (i.e. move the rotor) when tuning a particular channel when using an
>>     HDHomeRun.  I ran across this antenna rotor; might be a good
>>     candidate for a blaster application?
>>
>>
>> How many points do you need to target? If it is only two, then maybe two
>> antennas is a better idea?
>
> I was about to suggest the same, as scheduling gets icky with a HDHR
> connected to a rotor.
>
> How do you avoid trying to record show A on tuner A from direction A 
> while at the same time trying to record show B from tuner B from
> direction B?
>
> One solution would be multiple antennas with on coax feed each to a set
> of tuners that are each dedicated to one direction/antenna.
> (In MythTV you use one Video Source per coax feed)
>
> Another solution would be to combine two antennas into one coax feed.
> http://www.engadget.com/topics/hd/2006/01/30/ota-hd-demystified/
> Allowing all tuners to record all channels.
>
> Regards,
> Karl
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> mythtv-users at mythtv.org
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>
As I understand, the cable companies do something similar by aiming a 
custom channel-tuned antennas directly at the local broadcasting 
towers.  I was considering putting multiple antennas on a single pole, 
each aimed appropriately, until I read an article about antenna 
separation; not sure, but I think that only applies when transmitting 
(might have been a ham site I was reading).  If separation doesn't 
affect receiving, maybe I should reconsider.

I'm not sure how many to target.  My existing antenna rotor doesn't work 
at all, so it's hard to experiment.  The farthest station is 50 miles 
away, so I'm guessing a good quality antenna will work for it.  The 
stations are located like this; it looks like I might need three or 
more, but it's  hard to tell.

http://users.zoominternet.net/~dlbrett/ScreenCapture_346.jpg
http://users.zoominternet.net/~dlbrett/ScreenCapture_347.jpg

RF Channel 33 - 18 miles @ 109 °
RF Channel 25 - 49 miles @ 140 °
RF Channel 09 - 48 miles @ 180 °

RF Channel 45 - 18 miles @ 240 °
RF Channel 23 - 50 miles @ 273 °
RF Channel 47 - 38 miles @ 278 °

RF Channel 41 - 02 miles @ 311 °
RF Channel 19 - 02 miles @ 312 °
RF Channel 36 - 02 miles @ 329 °
RF Channel 44 - 03 miles @ 336°
RF Channel 20 - 03 miles @ 336 °

By the  way, the existing antenna cable is connected to the HDHR box.  
Channels 36 and 41 work well most of the time, channel 20 is 50/50 
(pixalates a lot, hard to tune while raining).  I'm not sure of the 
condition of the connections at the antenna (they may be rusty or 
broken-off).

I inherited the HDHR box, and it's the single antenna model.  For the 
moment, I only have a single antenna feed to consider, but if this works 
out, adding another HDHR box is possible.  Sounds like the multi-antenna 
approach might be simpler; it seems that the popular way of interfacing 
rotor aiming with mythtv is a 
custom-script/lirc/system-event/tuner-timeout exercise; kind of a 
bolt-on, but people are reporting good success with it.

Not sure of which approach to pursue; any suggestions on how many 
antenna to use?



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