Importance of your String Test!

Captain Midnight

Captain Midnight

Thread Starter
SatelliteGuys Pro
Sep 16, 2019
545
369
Greers Ferry, Arkansas
I got out and tinkered with my 10ft Odom BUD I saved from a golf course. It is a good performer for being older than myself.

But it has one flaw.

There is a slight bend in it that has caused it to loose shape. It is not very noticeable during a string test. But enough to see room for improvement in some signal quality readings.

So I will stress the importance of a string test. It is essential with locking higher FEC digital signals to have a true shapen dish. I checked mine top to bottom and side to side and noticed that my side to side string tugged my top-bottom string down 1/2". It didn't seem like much. Until I decided to put tension on that string and the shape became true. My quality % improved up to 5-6% on many transponders!

And I didn't bother taking my old BUD apart. Lazy, I know but the hardware like bolts and nuts have 30+ years of "age". I'd have been replacing them left and right while trying to disassemble it.

Here is a cheap freebie tip. I used paracord from the Dollar Tree and a turnbuckle from a local supply shop. Took 10 min to throw on. And the paracord is nearly invisible at first sight.

Next project will be new paint!
 

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A

a33

SatelliteGuys Pro
Feb 4, 2015
639
420
netherlands europe
So I will stress the importance of a string test. It is essential with locking higher FEC digital signals to have a true shapen dish. I checked mine top to bottom and side to side and noticed that my side to side string tugged my top-bottom string down 1/2". It didn't seem like much. Until I decided to put tension on that string and the shape became true. My quality % improved up to 5-6% on many transponders!

Well done!

I notice on the forums that people often don't do string tests, or dish measurements to check the focal point position.
The latter I find especially usefull when having an offset antenna, as the LNB-arm does not always end at the right place/height.

Even when people write they want to check their focal point position, and when they are given the info where to measure the dish, it seems too much hassle, as they never post the measurements...?

Now I know there are a few calculators on the internet that have incorrectnesses (ParabolaCalculator2.0, and the Satsig-calculator), and I know that the proof of focal point is in the testing, not in the calculating.
But I'm surprised that people often don't want to check and know, if they are really using their dish to its possibilities.

So, well done, Captain Midnight! I support your argument!

Greetz,
A33
 
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Captain Midnight

Captain Midnight

Thread Starter
SatelliteGuys Pro
Sep 16, 2019
545
369
Greers Ferry, Arkansas
It is easy to overlook. But also easy to check!

I used paracord to avoid any signal attenuation or refections, but if the cord stretches too often, I may switch to 18ga Steel wire.
 
O

OswaldFTA

Active SatelliteGuys Member
Oct 8, 2021
20
10
Miami
I got out and tinkered with my 10ft Odom BUD I saved from a golf course. It is a good performer for being older than myself.

But it has one flaw.

There is a slight bend in it that has caused it to loose shape. It is not very noticeable during a string test. But enough to see room for improvement in some signal quality readings.

So I will stress the importance of a string test. It is essential with locking higher FEC digital signals to have a true shapen dish. I checked mine top to bottom and side to side and noticed that my side to side string tugged my top-bottom string down 1/2". It didn't seem like much. Until I decided to put tension on that string and the shape became true. My quality % improved up to 5-6% on many transponders!

And I didn't bother taking my old BUD apart. Lazy, I know but the hardware like bolts and nuts have 30+ years of "age". I'd have been replacing them left and right while trying to disassemble it.

Here is a cheap freebie tip. I used paracord from the Dollar Tree and a turnbuckle from a local supply shop. Took 10 min to throw on. And the paracord is nearly invisible at first sight.

Next project will be new paint!
Hello

Would you have more pictures of your dish? I got an old dish and trying to identify the manufacturer. I think that is a 10 feet Odom.
 
Cham

Cham

VE4GLS
Pub Member / Supporter
Dec 19, 2008
2,470
1,019
Boonies
Always the first to-do when looking at a used dish reflector. A step ladder, tape, and some string; it's saved me a lot of grief in the past identifying lost-causes etc.
Some of the older fiberglass dish reflectors have a bit of warpage just from being installed for many years. Often these can be re-installed upside-down and work fine. They initialy fail the string test, which can be a bargaining point when deciding on a purchase (or freebie).. and almost test perfect when re-installed that way. :)
 

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