Proper length of P* 84e feed support arm

[K'bick]

By the way, I have a total 4 P* 84e arms and out of them only one has the cast aluminum feed holder securely stamped to the arm's aluminum channel. The others have about 1-2 degrees of play if you grab the feed holder and wiggle it relative to the arm. You all might want to check yours too and if it moves have a welding shop tack it in place for a few dollars - this doesn't seem like a good place to have even the slightest movement.

 

[K'bick]

WT, I've been told they were relatively uncommon, but some of the (later model?) P* "coke can" LNBFs had a single (voltage-controlled H & V) output, no switch required.

Also, if any one has a pic of the dual-LNBF Primestar, please post in this thread or PM me for email addy info, I'd like to see one of those.

The LNB that came with my WSNet 84e setup had a brand new Eagle Aspen P270KU which features dual outputs each with voltage-controlled H/V. Here is a pic of the LNB (still attached to the smaller feed horn). After I get the larger feed horn cleaned up I will bolt it to this LNB.

Also I am attaching a pdf doc that has the specs of this LNB if anyone is interested.

 

[phlatwound]

....I'll need to locate a 75e arm somewhere down the road.

If you are unable to scrounge one:

https://www.impaktproducts.com/Channel-Master-Support-Arm-75E-p-16487.html

 

[ziggy1222]

"I found out (thanks to all of you sharing your measurements) that I had only 84e arms all along. Even my 75e came with an 84e arm - fine for what I want to do with the 84e dish (bring it back to a "stock" P* feed setup) and bad for when I find a use for the 75e.. I'll need to locate a 75e arm somewhere down the road. "

Thats great news...you can shorten one of your 84e arms with a hacksaw and drill a new hole in it for the mounting bolt thereby making it a 75e arm. You got to shorten it by 1 1/2" and the mounting hole sits back just about 1 3/16". The center insert threads with your mounting bolt and slides right out.

 

[K'bick]

Thanks Phlat and Ziggy,

I got one of my "extra" 84e arms from Impakt (it came today). I ordered it a few days back when I thought I had only 75e arms !sadroll ... then I got all the measurements from this thread.

Thats an interesting idea about shortening the 85e arm. There is no difference in the 75e and 84e lnb holders' heights or angles? Its only the length of the arm?

 

[ziggy1222]

"Thats an interesting idea about shortening the 85e arm. There is no difference in the 75e and 84e lnb holders' heights or angles? Its only the length of the arm? "

The only difference is the length of the arm. I have placed both arms on the patio next to each other in my response to you to take accurate measurments...they look identical in every other way except for the length.

Attached are some pictures...please note how the beginning of my tape measure catches some length from the slant on the LNB holder. Also note that the bolt is an 8.8 metric.

This probably goes without saying but I will say it anyway. In order to make this modification near factory perfect I would draw a line all the way around the arm; hacksaw from different sides slightly above my line and file smoothly so as to get a square cut. I would also drill pilot holes 1 3/16" down on each side from my square cut to make sure the holes for the bolt was straight. If you look closely at your dish you will see that the arm butts up against a lip on the back of the dish...measure the distance from this lip to the threaded hole to see if it is in fact 1 3/16". You want this arm to butt up tight to the lip so that it doesn't swivel.

 

[K'bick]

"Thats an interesting idea about shortening the 85e arm. There is no difference in the 75e and 84e lnb holders' heights or angles? Its only the length of the arm? "

The only difference is the length of the arm. I have placed both arms on the patio next to each other in my response to you to take accurate measurments...they look identical in every other way except for the length.

Attached are some pictures...please note how the beginning of my tape measure catches some length from the slant on the LNB holder. Also note that the bolt is an 8.8 metric.

This probably goes without saying but I will say it anyway. In order to make this modification near factory perfect I would draw a line all the way around the arm; hacksaw from different sides slightly above my line and file smoothly so as to get a square cut. I would also drill pilot holes 1 3/16" down on each side from my square cut to make sure the holes for the bolt was straight. If you look closely at your dish you will see that the arm butts up against a lip on the back of the dish...measure the distance from this lip to the threaded hole to see if it is in fact 1 3/16". You want this arm to butt up tight to the lip so that it doesn't swivel.

Thanks a lot for the pictures Ziggy - that helps a lot!