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2m interference with Dish?


carl.wf6j@gmail.com
 

I am mounting my 2m vertical on the back top roof edge here at my duplex.  There are two DISH antennas mounted there also. One high near the peak (multi band) and one lower on the edge (single band).  Appears they were located as to not block the other’s sat signal.

OK, so I have a mount and want to locate the vertical (2m like DX50) either between them (interference?) or I’ll pick the less desirable lower edge position. 

The antenna, no transmit, might block signal with the lower antenna dish ?  
(Might also consider. An extension mast from my mount, putting the vertical above the signal path of lower dish).

Q-When I transmit, do you think the signal will wipe out their sat reception?

(Will they actually know why?… who?)

Any answers helpful. Would bring up on the Elmer Net, but that will not be until October 7th (please note and check in).

TNX,
73,
Carl, WF6J

Top roof peak and the two dishes.Plan to mount either between them or lower than the closest dish and the gutter.
Prefer the higher mounting





Wayne - W6DT
 

Hi Carl,
Maybe the first question to answer is "Are the dishes actually in use?" Have seen many left when the service is terminated. 

Wayne  -  W6DT

On Sat, Sep 26, 2020 at 3:16 PM carl.wf6j@... <carl.wf6j@...> wrote:
I am mounting my 2m vertical on the back top roof edge here at my duplex.  There are two DISH antennas mounted there also. One high near the peak (multi band) and one lower on the edge (single band).  Appears they were located as to not block the other’s sat signal.

OK, so I have a mount and want to locate the vertical (2m like DX50) either between them (interference?) or I’ll pick the less desirable lower edge position. 

The antenna, no transmit, might block signal with the lower antenna dish ?  
(Might also consider. An extension mast from my mount, putting the vertical above the signal path of lower dish).

Q-When I transmit, do you think the signal will wipe out their sat reception?

(Will they actually know why?… who?)

Any answers helpful. Would bring up on the Elmer Net, but that will not be until October 7th (please note and check in).

TNX,
73,
Carl, WF6J

Top roof peak and the two dishes.Plan to mount either between them or lower than the closest dish and the gutter.
Prefer the higher mounting





Alan - W6WN
 

These both look like DirecTV dishes. The lower, single-LNB antenna is most likely disconnected since that's a single-satellite style that hasn't been used by either DirecTV or Dish for at least 10~15 years. The upper one is more likely to be in use, although it also is an abandoned design that may also be out of service. Normally, a DirecTV Technician would have replaced that LNB on the upper dish at least five years ago for any new receiver install. 

Two potential types of interference, physical Line of Sight and RF.

I suppose RF interference is possible but unlikely because the satellite frequencies are in the 20 ~ 30 gigahertz range to the LNB, and the LNB down-converts them to L Band at 950 ~ 1,450 MHz.

Line Of Sight Interference (really just some signal attenuation) could occur if you put the antenna within the antenna's aperture. The Line of Sight aperture is a cylinder the same diameter as the dish, and extending between the dish and the satellite. These are offset dishes, meaning that the actual direction and space occupied by that cylinder to the satellite is at least 20° higher than where the dish face appears to be pointing. For DirecTV, that's about 40° in elevation to the 3 satellites currently used. Stay out of that cylinder and you should be fine. 


Alan - W6WN
 

BTW, DirecTV Techs are no longer allowed to get onto a roof for repairs or new installs, and haven't been for several years now.

From the looks of where the upper dish is located, it's most likely abandoned or will be in favor of a 100% ladder-accessible location. If this is just a duplex, ask your neighbor if he currently has DirecTV. If he doesn't, you're good to go. If he does, look for other, newer DirecTV dishes elsewhere on the wall or roof. 


carl.wf6j@gmail.com
 

Thanks.  Yes Brian send me. a diagram and info (specs) on the dishes.  Yes they are both in use (darn it). I’m not sure of the frequency. They are recently installed AT&T “Dish Antenna” units.



On Sep 26, 2020, at 9:12 PM, Wayne Stilwell <dx4wayne@...> wrote:

Hi Carl,
Maybe the first question to answer is "Are the dishes actually in use?" Have seen many left when the service is terminated. 

Wayne  -  W6DT

On Sep 26, 2020, at 9:06 PM, Greg D <ko6th.greg@...> wrote:

Hi Carl,

Brian might know the answer to this...  Any idea what frequency the IF is running between the dish and the stuff in the house?  I think that could be the biggest risk, if they're anywhere near the same band.  Or, is it a digital signal between the dish and the house, and fairly immune from being de-sensed?  The satellite downlink itself is in the 10 ghz range, so not a problem there.

Greg  KO6TH





carl.wf6j@gmail.com
 

They might be Direct TV ( just said Dish) As they were installed within the past year. The last one was done about 6 months ago by an AT&T Tech (the lower one) and from a ladder access to the lower portion of the roof.

Carl, WF6J

On Sep 26, 2020, at 9:25 PM, Alan - W6WN <Alan.W6WN@...> wrote:

BTW, DirecTV Techs are no longer allowed to get onto a roof for repairs or new installs, and haven't been for several years now. 

From the looks of where the upper dish is located, it's most likely abandoned or will be in favor of a 100% ladder-accessible location. If this is just a duplex, ask your neighbor if he currently has DirecTV. If he doesn't, you're good to go. If he does, look for other, newer DirecTV dishes elsewhere on the wall or roof. 
_._,_._,_


Alan - W6WN
 

Then does DirecTV have a central head-end installed for the complex there? I can't imagine them installing a single-satellite antenna for anything other than adding a satellite they were missing. Certainly not for an individual user.


Gerry - WA6E
 

Kind of off topic - but who installs the dishes for DirecTV if their techs can't get on the roof?

Gerry
WA6E

On 9/26/2020 9:25 PM, Alan - W6WN wrote:
BTW, DirecTV Techs are no longer allowed to get onto a roof for repairs or new installs, and haven't been for several years now.

From the looks of where the upper dish is located, it's most likely abandoned or will be in favor of a 100% ladder-accessible location. If this is just a duplex, ask your neighbor if he currently has DirecTV. If he doesn't, you're good to go. If he does, look for other, newer DirecTV dishes elsewhere on the wall or roof. 


Alan - W6WN
 

For new installs, DirecTV Techs will only work from ladders, and will install a new antenna instead of going off-ladder to reach an existing antenna.

There are some independent Techs who will do repairs off-ladder. The DirecTV Techs used to refer work to me and I've done several. But I no long take these jobs because I'm too busy and pretty much dropped satellite TV from my list.

After they took over DirecTV a few years ago, AT&T all but destroyed their local, independent Retailer base. I don't know of any independent Techs/Retailers doing new installs in the area. Most Sat TV Retailers fled to Dish Network. Possibly Jared from Gold Country Satellite in Grass Valley still does DirecTV repairs but he doesn't advertise that on his web site.


Brian Gohl - AI6US
 

Carl,

Thank you for confirming that the screenshot ithat I provided is gor your address.

The aiming line that is shown on the screenshot is the furthest West that either dish would be aimed to receive satellite programming. All satellite positions used by either Dish Network or DirecTV are to the East of the eave line. 

A VHF/UHF antenna mounted on this fascia will not block the line of sight to either the Dish Network or DirecTV satellites.

The proximity of the coax cable will not be an issue either.
--
Brian- AI6US