24" dish gets worse signal than a 20"??

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Mr Tony

SatelliteGuys Pro
Original poster
Supporting Founder
Nov 17, 2003
3,040
13,679
Mankato, MN
Need some help here.

I decided to replace my ExpressVu dish (Dish500) with a 24" dish to help rain fade. My skew is basically 90, so I figured i'd jam the "Y" adapter with the 2 dual LNB's and we should be all set

WRONG!

I jammed the "Y" in there and placed it in place of the 20" start messing around and I get signal. Play around with it for about 20 minutes and the best I can get is........60

The 20" gave me readings around 80 for all TP's!!! (on a scale of 1-100)

Nedless to say, with the temperature at 92 and the heat index around 105, I gave up, took down the dish and put the 20 back up.

Do these 24" dishes need the LNB to be head on (like the old 18" dishes use to?). Is the reason the signal went down because of the "Y" adapter and its not hitting the "sweet spot" of the dish?

I ordered a part from the dish store...An adapter that allows you to place a Dish LNB on a rectangle mast on the dish
http://www.dishstore.net/product_info.php?cPath=48&products_id=146

Hopefully that will help....but is that the reason of the lower signal, because its not hitting the sweet spot?
 
Are the arm lengths the same on both dishes? I.E. the standard Dish 500 arm is shorter then a standard D* round dish. If the 24" you are using has a longer arm length, the Y adapter would then place the LNBs even further away from the dish; is it possible that this changes the focal point? Just a guess.
 
I dont know...have to check

When I originally did this, it was Wednesday, and due to the heat I really didnt want to mess with it for long. Last night I just put the pan in front of the 20" and got the same results.

I have a feeling that the LNB has to be at the end of the arm (and not on the "Y" adapter)
 
Perplexed. Called two of my techs. Everyone agrees that it should work. Only thing that came up was the LNB distance to the dish, but you have already eliminated that by dropping the pan in front of the 20" and got the same results. Your profile says that you have 5 dishes, time to go for 6? :D

Seriously though ...

Does your meter measure carrier to noise ratios (or if you are using a spectrum analyzer disregard) and if so, what kind of readings are you getting?
 
CablerMN said:
Perplexed. Called two of my techs. Everyone agrees that it should work. Only thing that came up was the LNB distance to the dish, but you have already eliminated that by dropping the pan in front of the 20" and got the same results. Your profile says that you have 5 dishes, time to go for 6? :D
Click to expand...

No. replacing the 20" for ExpressVu for a 24" (less rain fade)
Seriously though ...

Does your meter measure carrier to noise ratios (or if you are using a spectrum analyzer disregard) and if so, what kind of readings are you getting?
Click to expand...

meter? why would I use one of those?? :D :rolleyes:
prop the little TV in the window, menu 6,1,1 on the system and see the bar right there. I dont have a meter. I can adjust all my dishes by using the TV method.

I'll work on it on Monday when my part arrives :)
 
I found out on another site that the Y adapter does hinder the signal strength. Looks like I'll ben using the 24" for 91 and the 18" for 82.
 
Look at the Multifeed section of my website for some ideas on putting more than one satellite feed onto a dish www.global-cm.net

Since you already have a 24-inch dish, I would install the LNBF for 82
with the rectangular tube attached to it at center. Then, looking from the front of the antenna, take the other LNBF (for 91) and go to the right and slightly lower; just wave it in the air off to the side of the previously mounted LNBF and look for the hot spot of signal. I have heard of people using a LEGO block as a spacer, and hose clamping around both LNBFs.
The trick is to get it stable. 24 inch antennas do not have the skew adjustment in back (in most cases) so you have to compensate for the elevation shift at the LNBF. Waving the 91 LNBF for best placement and then carving a wood block with a table saw to allow secure but accurate spacing...and then adding a hose clamp or two should do the trick...if you
are less than happy with the 2-LNBF adapter.

Back to my website: we offer an 84 cm Channel Master elliptical that has been modified with a bracket that allows multiple LNBFs to be attached at front. It would be no problem to physically do 91-101-110 and 119 on the same antenna, and if you were more worried about getting another satellite on the same reflector as opposed to signal strength, you could squeeze in
the 82 NIMIQ satellite on the same dish. We have another variation of this
for HDTV buffs, that might be considered. Get two of these 84 cm dishes
and set one up for VOOM at 61.5 DBS and their soon to be added 72 Ku,
plus ExpressVu at 82....centering on the 72 slot. The second dish could
do 91-101-110 and 119.

Mike
 
mikekohl said:
Look at the Multifeed section of my website for some ideas on putting more than one satellite feed onto a dish www.global-cm.net

Since you already have a 24-inch dish, I would install the LNBF for 82
with the rectangular tube attached to it at center. Then, looking from the front of the antenna, take the other LNBF (for 91) and go to the right and slightly lower; just wave it in the air off to the side of the previously mounted LNBF and look for the hot spot of signal. I have heard of people using a LEGO block as a spacer, and hose clamping around both LNBFs.
The trick is to get it stable. 24 inch antennas do not have the skew adjustment in back (in most cases) so you have to compensate for the elevation shift at the LNBF. Waving the 91 LNBF for best placement and then carving a wood block with a table saw to allow secure but accurate spacing...and then adding a hose clamp or two should do the trick...if you
are less than happy with the 2-LNBF adapter.

Mike
Click to expand...

Mike
I would rather use the 24" for 91, as most of my programming is on there. Skew in Mn is almost 90 (I was getting good signal on both with the 20" at 90). I'll be getting the adapter today and will work on it tonight. Probably end up using the 18" dish I have up there for 82 and the 24" for 91.
 
Well I got my adapters last night and tried this again

Installed the 24 in the same spot as the 20, tuned it and got..........60

grrrrrrrrr :mad: :mad:

Tried using one of my 30" dishes. Attached the adapter to the mast of the 30" (more or less rigged it), starting tuning it
0....40......0......40.......adjusted the elevation a little more......95 (on a scale of 100!!!)

So now I have a 30" for 91 and using my 20" for 82

So the 24" dish must have been defective
 
Monday night I worked on getting better signal strength with the 30" dish. I took a Dish Network dual LNBF and gutted the plastic off by the "eye" (the plastic housing around the guts of the LNB) and wrapped duct tape around the LNB (right behind the "eye"). I needed to make it fit in the FTA bracket so I needed about 1/2" of duct tape. Installed it and did a test....

0

Loosened the bolts on the elevation scale and let it drop down to the bottom. Saw the bar jump and then go back to 0. Slowly moved it back up, and lo and behold, got it to hit at 100!! So I finally got this to work

1..100
2..100
3..100
4..100
5..100
6..99
7..100
8..97
9..100
10.100
11.100
12.95
13.94
14.100
15.97
16.83
17.100
18.96
19.100
20.100
21.100
22.96
23.100
24.84
25.80
26.96
27.83
28.90
29.100
30.100
31.100
32.100

17 out of 32 hitting at 100 :)
 

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