Dish and equipment upgrades - What to do

[hesnodgrass]

Hello all,


As I wait to get my new receiver I am testing my installed FTA system.


I currently have a 7 year old setup - a 31" dish with an Invocom QPH-031 quad LNB running on a SG2100 motor. The Linear and circular outputs are going through a Chieta 4x1 switch. I have a long run from the LNB to the receiver of about 60 to 70 feet. I am using RG6 Quad cable for all connections. Before I get my new receiver I powered up my old Viewsat Ultra VS2000 and ran some tests. My Q meter on 97 on most TPs is around 60 on the stronger TPs. When I go to 83 to tune in RTV my Q is around 38 to 40. On 103 I get about the same on the two beach channels with a QA of around 40. On 123 I get a Q of around 75. I tried nudging the dish east and west with the viewsat and only saw drop and no improvement. I remember that my Q was much higher back when the system was installed and am trying to figure out what adjustments and changes I need to do to improve my signal quality? Will a 36" dish give me that much improvement? Also can an LNB age or lose quality over time and would buying a new LNB maybe help? If so is there a better one out there now then the one I have? I find it interesting that the furthest west of 123 has a better signal. I am at 75.7 W.


Thanks for all the input

 

[turbosat]

Bigger dish will usually help, 31" is a bit small, but should be ok for most SD ku stuff. If you're getting higher signal quality on one end of the arc your dish possibly isn't tracking as well as it could be. Time to drag the power cords and tv/receiver out to the dish and tweak tweak.
edit: And yes, if your lnbf is 7yrs old it could be showing some weakness with age, though I've never used that circ/linear combo invacom to know its lifespan.

 

[SatelliteAV]

The Invacom should still be outputting the same signal quality as it did 7 years ago. The Invacom QPH-031 LNBFs tend to drift frequency as they age, but usually will see no decrease in Signal Quality readings.

Try sliding the LNBF towards or away from the reflector to optimize the focal distance and you might check that the skew setting is still optimized.

Dishes can warp over time and maybe the dish might have been mistreated in your absence from the hobby. Check to see if the dish has been warped by performing a string test. Stretch a horizontal string from dish edge to dish edge and another vertical string. Do the two strings lightly touch in the center of the dish? If so, the reflector is still focusing the signals to the LNBF. If the strings are separated, the satellite signals will not converge correctly in the LNBF opening and result in lower signal quality.

 

[Anole]

Another possibility, is that the heavy weight of the QPH-031 over all these years, has distorted your LNB arm.
Just as a test (only), you might experiment with a string from the top of the dish to the LNBF neck.
Put a little tension on it and sees what happens.
If it helps, I'd get a new dish (36") and a modern LNBF.
Not much call for circular any more.

 

[johann12]

Check if your pole is still level, this could not track the arc right.

 

[KE4EST]

Yes if it was installed 7 years ago, several things could have happened. Like others have said it is time to get out at the dish and check it out for integrity and then do a fresh alignment of the system, starting with making sure the pole is still plumb.

What new receiver did you buy?

 

[AcWxRadar]

Hesnodgrass,

If you have the time and inkling to do so, here is what I would recommend with your EXISTING equipment.

Motor you dish to several satellites from your furthest east to nearest due south to furthest western satellite you can receive.
Make a log of one or two HOR TPs and one or two VER TPs on each satellite and record your signal quality readings from each.
Then, take your dish OFF the motor, remove the motor from the mast and install the dish on the mast and realign it as a single,
fixed point dish and recheck all the satellites and TPs that you did previously with the motor.

This will inform you of the BEST possible signal quality that you can expect from all of these satellites and TPs without the variable
of the H-H motor alignment entering into the equation. You see that without the motor, you can align the dish to the ultimate angle
for each sat and record the maximum signal quality you can achieve with your current dish, LNBF and receiver.

Now you can compare your previous results using the H-H motor with the best possible results from a single point dish, the same dish,
and that will verify if you had a MOTOR alignment issue or not. At least it will provide you with signal quality level "goals" to achieve when
incorporating your H-H motor.

Beyond this, you will be able to identify if you may have a problem with your equipment, beyond just an alignment issue.
If you know that you should probably read a signal quality level near 75% on a specific sat and TP, and you obtain only
55% with the motor or without, then you may have an LNBF with a major drift in the L.O. frequency, a poor tuner or
some similar defect. Basically, if you are doing your alignment appropriately, you can rule alignment out as a fault if you
try it with and without a motor and obtain the identical or nearly identical results.

You have to think in terms of "how many variables can I eliminate" to provide yourself with a baseline measurement, a
measurement that you can compare your results against as you test each and every hypothesis.

I hope that my reasoning here seems like a sound practice to you, I think it will benefit you if you subscribe to this approach.

Good Luck and happy hunting!

RADAR