New user - old Birdview

[bombu]

I

Removing the feed horn cover is very simple. Merely remove the center screw and pull it off…. Not. 45 years of entropy has left it very comfortable where it is. Should I spray it with something?

This is a lot more fun than the stuff I should be doing,

In the apparently unlikely case someone finds this when googling how to remove the cover - I sprayed it with wd-40, let it sit for a few hours and then hammered the tip of a thin flat screwdriver into the gap and twisted. The gap opened up a little so I went around the circumference inserting and twisting the screwdriver until the gap was about an eighth inch all around. Then I could pull the cover off by hand.

I had previously tried hitting it with a rubber hammer; this was ineffective and dented the cover.

 

[Titanium]

Your dish has great potential, but will require some modifications to accomodate changes in technology and usage since it was manufactured 40+ years ago.

As I suspected, this is an original Birdview LNA type feed. This type of feed is no longer in use and unsupported by receivers in use today. I would remove the feed hardware and only reuse the scalar. Clean and renew the scalar then hone the opening to accept a new larger LNBF throat diameter.

The Birdview FD (Focal Diameter ratio) is .39, but hobbyist, who have modded Birdview's in the past have reported success and good signal readings using current design feedhorns and modded Birdview scalar w/modded support legs to set correct FD and FL (Focal Length). Some hobbyists have addressed tbis FD and FL mismatch by fabricating new longer feed support legs, but this is a significant endeavor.

You will find several threads on this site and over on Rick's posted in the early 2000's on Birdview feed modificstions. Past threads also discuss the mount modifications for declination setting.

 

[bombu]

Oh well, I'm sorry to hear that but not surprised. Which is the scalar? Is it the aluminum structure with the fins, (presumably a wave guide)? I have access to CNC plasma tables and industrial 3d printers. Could I conceivably fabricate something that would work? Is it simply a matter of placing the new modern LNBF in the correct position?

Thanks again for your help and advice, all of you who responded. I see I have a great deal to learn and it's not going to be as simple as I'd hoped.

 

[primestar31]

Oh well, I'm sorry to hear that but not surprised. Which is the scalar? Is it the aluminum structure with the fins, (presumably a wave guide)? I have access to CNC plasma tables and industrial 3d printers. Could I conceivably fabricate something that would work? Is it simply a matter of placing the new modern LNBF in the correct position?

Thanks again for your help and advice, all of you who responded. I see I have a great deal to learn and it's not going to be as simple as I'd hoped.

There's this, lots of info: Pendragon vs. the Birdview

IMO, Ricks got the most info on Birdviews: https://rickcaylor.websitetoolbox.c...owas=threads&btnSearch=Search&action=doSearch

 

[bombu]

There's this, lots of info: Pendragon vs. the Birdview

IMO, Ricks got the most info on Birdviews: https://rickcaylor.websitetoolbox.c...owas=threads&btnSearch=Search&action=doSearch

Is it ok if I continue this thread here? I may get a bit off topic occasionally. I don't want to annoy anyone or waste their time but I might want to post about my progress, thoughts and experiences.

 

[primestar31]

Is it ok if I continue this thread here? I may get a bit off topic occasionally. I don't want to annoy anyone or waste their time but I might want to post about my progress, thoughts and experiences.

Yes, I encourage you to leave it all in this thread here! I put those links there for you to read, to maybe figure out some things you need to do. There's good stuff from people that already did it.

 

[N6BY]

bombu,

I have a motorized 8.5' BirdView. It's my second one.

Am currently using it for KU band. I made a circular holder for a KU LNBF out of 1/2" expanded PVC (See photo). I also made a circular LNBF plate with two holes for dual KU / C-Band operation, but am not currently using it.

Mine came without feed support rods, so I had to make those out of threaded rods from the hardware store.

I would be happy to provide any construction details if you would like.

Brett

 

[bombu]

Great, thank you.

Titanium, is the .39 f/d ratio you cited from manufacturer's specifications or is it empirically determined? I stretched strings across and came up with 19 inches depth for a f/d ratios of .375. Google's Gemini ai chatbot suggested a f/d ratio of .38 (for an early '80s 9.5' solid Birdview) which implies a depth of 18.75 inches. The exact diameter is also a bit fuzzy since the edges are rolled. Also, getting my strings exactly over the center of the dish is problematic.

It seems to me that measuring the signal strength and adjusting the LNBF to maximize the signal would be the only reliable method.

 

[telstar_1]

I

In the apparently unlikely case someone finds this when googling how to remove the cover - I sprayed it with wd-40, let it sit for a few hours and then hammered the tip of a thin flat screwdriver into the gap and twisted. The gap opened up a little so I went around the circumference inserting and twisting the screwdriver until the gap was about an eighth inch all around. Then I could pull the cover off by hand.

I had previously tried hitting it with a rubber hammer; this was ineffective and dented the cover.View attachment 181615View attachment 181617

Haven't seen one like that. That's a whole can of worms going on there.

The scalar is the plate with concentric rings (aka "scalar rings"). I remember way back an explanation for how they work, like they're bouncing signal back into the dish to be better focused on the center/waveguide. The waveguide is the round tube at center of scalar rings. The rectangular fittings for LNBs can also be referred to as waveguides. Basically it's anything that conducts the signal in air.

 

[phlatwound]

...It seems to me that measuring the signal strength and adjusting the LNBF to maximize the signal would be the only reliable method.

Yes, physical measurements and math should get you close, then tweak and peak for the best signal.