The larger the dish the narrower the beam width becomes, a satellite like 129 has a wobble that may take it out of the beam for large satellite dishes. Next year when the replacement is in use the large dish probably won't be needed.
Any have experience with 4 ft or larger DBS antennas?
I've seen posts about folks using 48" antennas, but is anyone using larger antennas for home Dish Network installations? Someone I know can only partially see the 129 satellite from his cabin deep in the woods. For reliable reception, he installed larger and larger antennas and finally a 7 foot antenna (a fiberglass C band throw away) did the trick. Aiming took forever and keeping the antenna fixed on the satellite is a chore. Are there any special considerations to be take into account when installing antennas this size for Dishwork Network reception?
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why is it that a larger dish narrows the beam width, I would think the opposite would be true.... not that it is or that i am disagreeing... can you explain why this is?
try a google search for "satellite dish beam width " You should be able to get a little education about dish design.aloishus27 said:why is it that a larger dish narrows the beam width, I would think the opposite would be true.... not that it is or that i am disagreeing... can you explain why this is?
A non-technical answer -- It's like blinders on a horse, a bigger dish is like a bigger blinder, so your "horse" sees a smaller point in the sky.
aloishus27 said:why is it that a larger dish narrows the beam width, I would think the opposite would be true.... not that it is or that i am disagreeing... can you explain why this is?
Simple. The larger the dish, the narrower (sharper) the focus.aloishus27 said:why is it that a larger dish narrows the beam width, I would think the opposite would be true.... not that it is or that i am disagreeing... can you explain why this is?
I have a 4' pointed at 119 and a 6' pointed at 110.
The 6' is susceptible to wind shaking it, so I have an adjustable brace to the edge of the dish at the 3 o'clock position. I made it adjustable because moving the edge of the dish 1/2" inch is enough to drop the signal to zero.
The 6' is susceptible to wind shaking it, so I have an adjustable brace to the edge of the dish at the 3 o'clock position. I made it adjustable because moving the edge of the dish 1/2" inch is enough to drop the signal to zero.
There used to be a guy at DBSForums, Raphiel, who operated a private cable system of sorts in Venezuela that used a couple of 12 foot dishes pointed at two different DirecTV satellites in the 101 slot that were typically only 3/10 of a degree apart.
Last I knew, DirecTV would not allow commercial installers to use dishes larger than 4 feet in diameter because they were concerned that they might not properly target two or more of the satellites in the 101 slot, but if DISH is only using one satellite at 129, the "figure eight" drift of that satellite should not cause any problem with any size large fixed dish that you might use.
Feedhorn positioning is critical in large Ku set-ups, and what really makes the placement demanding is that the abandoned C-band dishes have lowed f/D ratios than do typical Ku dishes, so the signals reflected from the periphery of the dish come into the feedhorn at a wide angle. An optimal feedhorn assembly for receiving Ku from such a shallow dish is probably a feedhorn in which the probe is out in front of the LNB, rather than recessed back in a waveguide tube.
I was once called out to service the headend of Muslim Television of America. They have a gigantic (maybe 25 to 30 foot) polar mounted dish fitted with a Ku feedhorn that they are dissatisfied with and asked me about peaking it for them. I told them I wouldn't touch it with a ten foot pole. In fact I couldn't reach it with a ten foot pole. nor would I attempt to with a thirty foot gantry, since if I move it even a fraction of a inch, I might lose the signal completely and never be able to find it again.
Last I knew, DirecTV would not allow commercial installers to use dishes larger than 4 feet in diameter because they were concerned that they might not properly target two or more of the satellites in the 101 slot, but if DISH is only using one satellite at 129, the "figure eight" drift of that satellite should not cause any problem with any size large fixed dish that you might use.
Feedhorn positioning is critical in large Ku set-ups, and what really makes the placement demanding is that the abandoned C-band dishes have lowed f/D ratios than do typical Ku dishes, so the signals reflected from the periphery of the dish come into the feedhorn at a wide angle. An optimal feedhorn assembly for receiving Ku from such a shallow dish is probably a feedhorn in which the probe is out in front of the LNB, rather than recessed back in a waveguide tube.
I was once called out to service the headend of Muslim Television of America. They have a gigantic (maybe 25 to 30 foot) polar mounted dish fitted with a Ku feedhorn that they are dissatisfied with and asked me about peaking it for them. I told them I wouldn't touch it with a ten foot pole. In fact I couldn't reach it with a ten foot pole. nor would I attempt to with a thirty foot gantry, since if I move it even a fraction of a inch, I might lose the signal completely and never be able to find it again.
Great post!
ps. What's the tower by the Holiday Inn at Tysons? It's been there forever.
ps. What's the tower by the Holiday Inn at Tysons? It's been there forever.
I'm not sure where you mean. There is a tower just north of where Route 50 crosses 495 that has the WNVC channel 56/57 (soon to become digital channel 24) transmitter on it, as well as some strong radio stations that gave me fits when I installed an amplified FM antenna at the Red Cross headquarters at Jefferson park a decade ago.blooker68 said:Great post!
ps. What's the tower by the Holiday Inn at Tysons? It's been there forever.
It's a self supporting, 4 leg tower, now red and white, about 100 ft tall, that sits on a knoll 1/4 mi NW of the Rt 7/Rt 123 intersection.
Might that actually be Merrifield? Last year that tower was used for a low powered channel 6 analog carrying programming from Equador that gave fits to master antenna systems that had been using vacant channel 6 for downconverted UHF. I don't know what else is on that tower.
This is really too far off-topic to be of interest to anyone else here, but over at AVSForums, you MIGHT get a response to similar questions if posted in the Washington, DC locals thread.
This is really too far off-topic to be of interest to anyone else here, but over at AVSForums, you MIGHT get a response to similar questions if posted in the Washington, DC locals thread.
Why worry about 129, use 61.5
Can't see the 61.5 bird from his location.
He wishes he could.
He wishes he could.
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