Alternative Dish materials...

[VK2UL]

Does anyone have suggestions on alternative surface materials to recover an old 5m C Band dish ?

The old surface, expanded AL mesh is in poor shape but replacement AL mesh is ridiculously expensive and not easy to procure is useful sizes.

Has anyone tried galvanised 'vermin mesh', 6.35mm sq holes, 0.6mm wires. Its heavier than AL mesh and probably only good to 5GHz ?

Oh, I need a surface to cover 1.2GHz thru to 10Ghz.

Surprisingly solid AL sheet, 1.00mm thick, is one of the cheapest. Might do that if anyone else doesn't have a better idea...

opinions ?

cheers,
Geoff vk2ul

[VK4TI]

some sort of plastic and metal coat it ? , there has to be a paint surely ?

[VK3HZ]

Gal wire might rust out fairly quickly if it's in contact with Aluminium.
And ~6 mm holes may be too big for 10 GHz.

Bunnings sell Aluminium flywire.

Regards,
Dave
VK3HZ

[VK3OX]

Geoff,
If you need an alternative to 1mm thick aluminium sheet, you might consider using used aluminium offset printing plates. These are available from printing companies specialising in offset printing. From memory, they measure around 745mm by 605mm and are very thin, perhaps 0.1mm or even 0.05mm. In fact, they are so thin you can cut them to shape with a pair of ordinary scissors.

I would think they could be pop rivetted together and the joins then protected with a smear of silicone to keep the weather and corrosion out.

Once they are used by offset printers, they are usually dumped into bins for metal recycling. I'm sure you could do a deal and buy them for the price that the printers get from the scrap metal companies.

Rgds es 73, de Jim VK3OX

[VK2UL]

Gal wire might rust out fairly quickly if it's in contact with Aluminium.
And ~6 mm holes may be too big for 10 GHz.

Bunnings sell Aluminium flywire.

Regards,
Dave
VK3HZ

I live inland, 300km from the east coast, no sea air, no cities and humidity is generally lower so rust is far less of an issue. But you're right galvanic corrosion might be ? Yep, 6mm holes is only 1/5 lambda at 10Ghz, a bit too wide.

I previously checked out Aluminium flywire and even the heaviest stuff at Bunnings is too 'floppy' for a dish this size. Not sure its tough enough over 900mm spans, would be good for a grid pack dish

thanks anyway...

Geoff,
If you need an alternative to 1mm thick aluminium sheet, you might consider using used aluminium offset printing plates. These are available from printing companies specialising in offset printing. From memory, they measure around 745mm by 605mm and are very thin, perhaps 0.1mm or even 0.05mm. In fact, they are so thin you can cut them to shape with a pair of ordinary scissors.

I would think they could be pop rivetted together and the joins then protected with a smear of silicone to keep the weather and corrosion out.

Once they are used by offset printers, they are usually dumped into bins for metal recycling. I'm sure you could do a deal and buy them for the price that the printers get from the scrap metal companies.

Rgds es 73, de Jim VK3OX

Jim, 0.1mm might not survive a hailstorm ? Interesting idea, thanks..

cheers,
Geoff

[VK2UL]

All,

Found some heavier Aluminium Flyscreen at Bunnings, "Tuff Lite" by Cyclone. Its not as cheap but will do the job.

thanks all who helped...



cheers,
Geoff

[VK2ZIW]

If your dish has the same mount as Dave VK2JDS's 5m, the Elevation hinge joint
is very poor in design, being only 90mm wide and with 1mm slop in the shaft, a bolt.

In Satellite service, everything is bolted tight.

In Ham service, it is constantly being moved, so must be loose.

Alan VK2ZIW

[VK2UL]

If your dish has the same mount as Dave VK2JDS's 5m, the Elevation hinge joint
is very poor in design, being only 90mm wide and with 1mm slop in the shaft, a bolt.

In Satellite service, everything is bolted tight.

In Ham service, it is constantly being moved, so must be loose.

Alan VK2ZIW

Although this dish's elevation pivot is more substantial it does have slop. It was steered by screw-jacks in it previous life, there was some wear and round holes became ovals

I've already cut the previous mount up, back to not much more than a simple support ring then, I'll weld/machine up an entirely new elevation bearing arrangement.

At the end of the day not much of this dish will be original

cheers,
Geoff

[VK3NFI]

If your dish has the same mount as Dave VK2JDS's 5m, the Elevation hinge joint
is very poor in design, being only 90mm wide and with 1mm slop in the shaft, a bolt.

In Satellite service, everything is bolted tight.

In Ham service, it is constantly being moved, so must be loose.

Alan VK2ZIW

My Idea's on fixing the sloppy bolt mounting, Might be of some interest.
http://www.vklogger.com/forum/viewtopic ... 6&start=20
Cheers .