2db, 6" and $100 difference between dishes

[videobruce]

Someone explain this to me;

The Fortec 31" is $45 + $30 shipping,
the 36" model is $68 + $30,
the 39" model is $100 + $75

There is 2 dbi and $100 difference between the 31" and the 39". Is that REALLY noticeable other than on a meter? #-o
IOW's people claim that a 30" dish for FTA really isn't enough (I live in the NE), but how can you tell me an increase of 2 dbi is going to make a difference?

[Admin]

See explanation of dB here: https://ewhdbks.mugu.navy.mil/decibel.htm

In summary:
1dB gain equals to 126% increase in power gain
2dB gain equals to 158% increase in power gain
3dB gain equals to 200% increase in power gain

[bobkat]

videobruce... trust me on this:

There is a HUGE difference in signal strength between a 31" and a 39" dish. IMHO the extra cost is money well spent. You will suffer far less rain fade with a larger dish which translates into you are watching TV when your friends are watching the "No Signal" error message... :mozilla_cry:

We sell only 39" dishes now and rarely do we hear back from customers with the famous "No Signal" complaint. Makes it easier for them to install too !!

kat

[videobruce]

Admin; thanks for the link. I will scope it out.
I'm only going from my experiance with 2 way radios. Doubling your power doesn't double your range. In fact, it usually isn't that noticeable. Just looks great on a spec sheet which is what I'm getting at here.

bobkat; Hello neighbor. I'm not far from you on the other side of the pond. I hear what your saying, having a fudge factor. It's not only price, it's weight. I WANT (hopeing) to mount it on a upper rear porch post. I'm concerned about weight. The post is new wood (2 years old) and I would use bolts that are long enough to go through the 6" square collumn, but the concern is still there.
But, this is dependent IF I have a clear shot at the whole arc. It might be partially blocked by my roof and attic dormer.

[wejones]

In addition to the gain in signal strength, a 39" dish is significantly better with respect to resolution. With satellite spacing now often being in the 2 degree range, it is sometimes difficult to avoid interferrence between adjacent satellites. A 31" dish has a resolution somewhere between
1.9 and 2.2 degrees, depending on which equations you use, which is really marginal relative to the 2 degree spacing. On the other hand, a 39" dish will have a resolution between 1.5 and 1.8 degrees. You can see that the 39" dish will have a much easier time eliminating signals from adjacent satellites.
There is one drawback, however, and that is that the bigger dish will have to be aligned more accurately, because it will lose signal quicker when off target.

[videobruce]

I believe the proper term is beamwidth, not resolution.
Sounds as you are talking about video resolution e.g. number of lines. :mozilla_wink:

I wished I knew which satellites/transponders are on the border line where the larger dish would help. #-o

[wejones]

Originally Posted by videobruce

I believe the proper term is beamwidth, not resolution.
Sounds as you are talking about video resolution e.g. number of lines. :mozilla_wink:

I wished I knew which satellites/transponders are on the border line where the larger dish would help. #-o

I used the term resolution because some of the equations I used to calculate it come from radio astronomy, where they are trying to resolve signals between 2 stars or something, which is analogous to resolving signals from two adjacent satellites.
Re predicting what signals you'd have problems with, I don't know, other than looking at Lyngsat. It's not that common, but I've seen problems a couple times on C-band with my 10' dish, which is similar to the 3' dish on Ku. Had to move the dish slightly off center to get one channel to come in, because there was a signal on the adjacent sat with nearly the same parameters. You probably won't have any problem with most signals with the smaller dish, but it is another reason that bigger is better.

[kevision]

It's mostly the feeds that are a challenge to get. are you planning to watch many of those? if so, the bigger the better, as well as the lower dB LNB.

slightly off topic, but 'resolution' is the correct word when refering to discernment between signal sources.

[videobruce]

I was just thinking beamwidth of the antenna from my OTA & 2-way radio experiance with those antennas.
I get you.