Upside down offset dish

[Channel Hopper]

The slight increase in overall height on the pole will assist in clearing potential objects in the path, and help capature lower elevation satellites on certain kingpost/polarmount combinations.

 

[a33]

Well... there's potentially less ground noise

I've read somewhere that as the LNB looks down on an inverted dish (as opposed to looking up, towards a normally mounted offset dish) there is potentially MORE ground noise to be received.

Which is it?

Greetz, A33

 

[a33]

The slight increase in overall height on the pole will assist in clearing potential objects in the path, and help capature lower elevation satellites on certain kingpost/polarmount combinations.

That is --roughly speaking-- only the case when the pole mounting bracket is at the upper half of the dish.
Only then the (former) lower half reaches out higher above the pole, when the dish is inverted.

So this statement is only true with some dishes, with other dishes it is untrue.

It was all discussed in this thread: Usals problem & alignment

Greetz,
A33

 

[7mdish]

And finally the dish was ordered. I must wait some week to have it, hoping that it will be all OK.

 

[s-band]

I've read somewhere that as the LNB looks down on an inverted dish (as opposed to looking up, towards a normally mounted offset dish) there is potentially MORE ground noise to be received.

Which is it?

Greetz, A33

True, if the correct way up dish doesn't have buildings or trees behind it. I.e. the overspill only 'sees' sky. For an upside down dish, lay metal foil/mesh beneath it so it 'sees' sky. This also applies to PF dishes.

 

[Channel Hopper]

That is --roughly speaking-- only the case when the pole mounting bracket is at the upper half of the dish.
Only then the (former) lower half reaches out higher above the pole, when the dish is inverted.

So this statement is only true with some dishes, with other dishes it is untrue.

It was all discussed in this thread: Usals problem & alignment

Greetz,
A33

I did say 'certain kingpost/polarmount combinations'.

If I could see the drawings of the 2.4 mount that is being cobbled together on order a more informed answer could be provided.

The CM dish I acquired a month ago included a custom king post, about 6' in height and 6.6" diameter to take the official Az/El mount supplied by the manufacturer.
Whilst the CM design can be used in both normal and inverted configuration I have usually installed them - and Prodelins in the latter configuration to normalise the front / back weight distribution, though the disadvantage is the feed/LNB ends up requiring ladders to service/change.

I have not checked if the inversion makes a marked effect on thermal noise, this might be more important for hotter countries than the UK.

 

[7mdish]

So, I'm waiting for the dish, and I must wait a little bit because it will be delivered in about one month (I hope).
Obviously I asked for an RX-only setup, but I read that a RX/TX version of this dish is available, too. What about possible differences? I know about mechanical differences, particularly related to the arms that must retain so big and heavy TX feeds. But what about performances? Is this the same reflector or is it different?
Also, anyone knows what is the weight of the RX dish with its frame but without any mount? It is no less that 60 or 70kg I believe but I'm not sure. Thanks.

 

[Channel Hopper]

With its frame ?

The shipping weight of the 243 is in the specification from Raven. There are three types, two with the extended drop plate and one without.

A polarmount for the original Channel Master was , from memory almost the same as the smaller one.

There are two modifications from the latest incarnation of panels, one with a triangular feed arm (somebody will be along shortly) that requires a completely different feed assembly from the technical drawings.

 

[RimaNTSS]

So, I'm waiting for the dish,

I've lost the track.... can you specify what did you finally order? The dish, the type of feed and support for it?

 

[7mdish]

I ordered the Raven 2.4m offset dish with its inclined orbit Polar mount from SSS.
You can see here:

Satellite dishes with inclined orbit polar mount motors. Raven 2.4m motorised inclined orbit satellite dishes. Dual axis, 2 motor polar mounts. UK.

Satellite dishes with inclined orbit polar mount motors. Raven 2.4m motorised inclined orbit satellite dishes. Dual axis 2 motor polar mounts. UK. 36 volt inclined orbit motors. Satellite Superstore UK. Channel Master, Andrews, Satellite dish motors. Inclined orbit motors, Inclined orbit polar...

www.satellitesuperstore.co.uk

It is the 243 model I believe, but I have no idea about its weight (not shipping weight, just dish weight). Some weeks needed for delivery.

 

[Channel Hopper]

I ordered the Raven 2.4m offset dish with its inclined orbit Polar mount from SSS.
You can see here:

Satellite dishes with inclined orbit polar mount motors. Raven 2.4m motorised inclined orbit satellite dishes. Dual axis, 2 motor polar mounts. UK.

Satellite dishes with inclined orbit polar mount motors. Raven 2.4m motorised inclined orbit satellite dishes. Dual axis 2 motor polar mounts. UK. 36 volt inclined orbit motors. Satellite Superstore UK. Channel Master, Andrews, Satellite dish motors. Inclined orbit motors, Inclined orbit polar...

www.satellitesuperstore.co.uk

It is the 243 model I believe, but I have no idea about its weight (not shipping weight, just dish weight). Some weeks needed for delivery.

You have ordered the dish (19th August) but don't know the shipping cost ?

 

[7mdish]

So, I did not forget to update this thread. The problem is that..... I have no update to share for now!
Dish delivery was delayed until the first months of 2022, and the installation will be possible not earlier than next Spring. Believe me, it is difficult to wait so much, but it is.

 

[Manikm909]

you should have bought @moonbase dish!

 

[7mdish]

you should have bought @moonbase dish!

Well, just ordered, so I wait. Thanks.

 

[RimaNTSS]

@7mdish Do you have any updates on your brand new CM2.4m?

 

[7mdish]

@7mdish Do you have any updates on your brand new CM2.4m?

Latest delivery date is at the end of February.
Before that date I would not be able to install it, too cold here. So I hope to make my installation in coming Spring.
The project is clear now:
- 2.4m offset dish
- inclined orbit polarmount with two actuators (one 36 inches and one 12 inches)
- rotating Ku-band 2-ports feed by Viking
- two Ku-band PLL LNBs by SMW.
It is not a cheap setup, so my expectations are very high.
I surely will post updates when the job will be done.

 

[Manikm909]

wowsers - good luck!!!!

 

[RimaNTSS]

rotating Ku-band 2-ports feed by Viking

For such fancy piece of equipment, you better use a rain/snow cover.
Nice plans. Good luck!

 

[7mdish]

For such fancy piece of equipment, you better use a rain/snow cover.
Nice plans. Good luck!

Yes, rain cover is planned. Such devices must be protected against water and bad weather conditions. I let you know.

 

[7mdish]

So, after long long waiting due to many issues that we must solved, finally my new dish will be delivered probably during next week.
The dish is an offset CM 2.4m (Andrew, Raven, Skyware yet.... but it is always the same I believe).
Please note it is the receive-only version, not receive-trasmit one.
As I mentioned, I would like to test Viking 2-ports Ku-band motorised feedhorn that was originally designed for a Prodelin offset 1.8m dish but I hope in a good matching with such similar dishes.
Anyone can tell me the exact focal distance of this CM? I think that no problem will occur (I hope so) because the original arms and feed support will be replaced by new one built keeping in mind this specific feedhorn, but any advice from someone that made deep tests with this dish would be greatly appreciated. Thank you.