Ka lnb ?

[John]

This Ka band LNB is somehow meant to work with a modification but how ?

View attachment 143222

You can use it as is for Band A use , L/R circ poloriser left on for any 42East Turksat Circular signals or remove the poloriser and bolt the scalar feed directly to the ODU body for 19.2East Ka Linear pol Newsnet sng feeds, a method of attaching the big lump in the correct position on the feed arms / lnb holder can be challenging. - the mods are usually just stripping it down to recover the receiver board, mod the OMT if you want, change the rx crystal etc etc and you end up with what you see in the previous posts - depends how tech savy you are in doing the mods.

 

[zorrin]

You can use it as is for Band A use , L/R circ poloriser left on for any 42East Turksat Circular signals or remove the poloriser and bolt the scalar feed directly to the ODU body for 19.2East Ka Linear pol Newsnet sng feeds, a method of attaching the big lump in the correct position on the feed arms / lnb holder can be challenging. - the mods are usually just stripping it down to recover the receiver board, mod the OMT if you want, change the rx crystal etc etc and you end up with what you see in the previous posts - depends how tech savy you are in doing the mods.

@John , I think you are making a mistake.
The AN8002 without modification covers the B band from 19.2 to 20.2 GHz.



This is unfortunately the least used part of the Ka band for television.

 

[John]

@John , I think you are making a mistake.
The AN8002 without modification covers the B band from 19.2 to 20.2 GHz.

View attachment 143225

This is unfortunately the least used part of the Ka band for television.

Sorry, think your right - it was the AN8004 Band D i tested that worked 'as is'

 

[sat-tv-fan]

You can use it as is for Band A use , L/R circ poloriser left on for any 42East Turksat Circular signals or remove the poloriser and bolt the scalar feed directly to the ODU body for 19.2East Ka Linear pol Newsnet sng feeds, a method of attaching the big lump in the correct position on the feed arms / lnb holder can be challenging. - the mods are usually just stripping it down to recover the receiver board, mod the OMT if you want, change the rx crystal etc etc and you end up with what you see in the previous posts - depends how tech savy you are in doing the mods.

Erm right well I've no idea what you really mean. I need a how to youtube video for this ! My version is the AN8002 btw

 

[moonbase]

Erm right well I've no idea what you really mean. I need a how to youtube video for this ! My version is the AN8002 btw

For Ka-Band A the Hughes LNB that most members bought came from the Hughes HN9200 unit and not the AN8002 unit.
The AN8002 unit you have is for Ka-Band B as indicated by @zorrin in post 122 above.

If you want Ka-Band A or Ka-Band D you need a different unit (HN9200 for A, AN8004 for D)

 

[zorrin]

Erm right well I've no idea what you really mean. I need a how to youtube video for this ! My version is the AN8002 btw

As a reminder :

Ka A is normally stated as 18.2 - 19.2 GHz
Ka B is normally stated as 19.2 - 20.2 GHz
Ka C is normally stated as 20.2 - 21.2 GHz
Ka D is normally stated as 21.2 - 22.2 GHz

In the table below you can see the Ka frequencies and satellite polarizations with the type of band:

4.9°E 21579 H - 21634 H - band D
7.0°E 21547H - 21727H - band D
16.0°E 21534 H - 21612 H - band D
19.2°E 18507 V - 18774 H - band A
23.5°E 21575 H - band D
39.0°E 18862 L - band A
42.0°E 18739 L - 18774 L - band A

As you can see, only the A and D bands are used.

With your AN8002 for the moment you have band B
After modification you could have band A

This modification consists of changing the ocilator



And add some dielectric plate somewhere in.

If you haven't understood what I'm talking about, I think it's useless to advise you to look for someone here to do it for you...

 

[ozumo]

Erm right well I've no idea what you really mean. I need a how to youtube video for this ! My version is the AN8002 btw

If you still have the TBS 6903 connect it up and give it a go..

Newsnet on Ka Band A

@sat-tv-fan This is how I started on Ka Ka with Prodelin/Viasat 1.2m Band B It's stil the cheapest way of getting Newsnet that I know of. In order of difficulty: 1 Get a Gilat AN8002 ODU (outdoor unit) form an old broadband set-up, remove the polariser. Use only the RX port (ignore the TX it...

www.satellites.co.uk

 

[7mdish]

As a reminder :

Ka A is normally stated as 18.2 - 19.2 GHz
Ka B is normally stated as 19.2 - 20.2 GHz
Ka C is normally stated as 20.2 - 21.2 GHz
Ka D is normally stated as 21.2 - 22.2 GHz

Looking at SMW Ka band LNBs specs, it seems that a fifth range is available: it would be between 17.2 and 18.2 GHz.
I don't know if it was never used or there are plans to implement it.
Also, when band B and C was used in the past?
In general, I suspect that Ka band was so promising some years ago but it is slowly fading now, maybe for too variable signals during rainy or bad weather times. What do you think? Thanks.

 

[zorrin]

While looking for an orthomode for linear polarization in Ka band I came across the following document: A Simple Orthomode Transducer for Centimeter to Submillimeter Wavelengths

The orthomode seems to me possible to redo in 3D or in machining but we need the right dimensions.





Is someone strong enough to make the table of corespondence ?
And who is able to redo the orthome if we have the right dimensions ?

 

[sat-tv-fan]

As a reminder :

Ka A is normally stated as 18.2 - 19.2 GHz
Ka B is normally stated as 19.2 - 20.2 GHz
Ka C is normally stated as 20.2 - 21.2 GHz
Ka D is normally stated as 21.2 - 22.2 GHz

In the table below you can see the Ka frequencies and satellite polarizations with the type of band:

4.9°E 21579 H - 21634 H - band D
7.0°E 21547H - 21727H - band D
16.0°E 21534 H - 21612 H - band D
19.2°E 18507 V - 18774 H - band A
23.5°E 21575 H - band D
39.0°E 18862 L - band A
42.0°E 18739 L - 18774 L - band A

As you can see, only the A and D bands are used.

With your AN8002 for the moment you have band B
After modification you could have band A

This modification consists of changing the ocilator

View attachment 143231

And add some dielectric plate somewhere in.

If you haven't understood what I'm talking about, I think it's useless to advise you to look for someone here to do it for you...

Ok understand and thanks for explaining but Newsnet will remain a dream it seems unless I can find a band A ka LNB but then my 1m dish won't be big enough ?

 

[ozumo]

Ok understand and thanks for explaining but Newsnet will remain a dream it seems unless I can find a band A ka LNB but then my 1m dish won't be big enough ?

You can get Newsnet using an 8002, read what s-band wrote a few years ago:

Newsnet on Ka Band A

@sat-tv-fan This is how I started on Ka Ka with Prodelin/Viasat 1.2m Band B It's stil the cheapest way of getting Newsnet that I know of. In order of difficulty: 1 Get a Gilat AN8002 ODU (outdoor unit) form an old broadband set-up, remove the polariser. Use only the RX port (ignore the TX it...

www.satellites.co.uk

Your previous posts and profile suggest you have a TBS 6903 card, if so no difficult hardware mods are required. A larger dish may be needed but no harm trying..

 

[Channel Hopper]

While looking for an orthomode for linear polarization in Ka band I came across the following document: A Simple Orthomode Transducer for Centimeter to Submillimeter Wavelengths

The orthomode seems to me possible to redo in 3D or in machining but we need the right dimensions.

View attachment 143232

View attachment 143233

Is someone strong enough to make the table of corespondence ?
And who is able to redo the orthome if we have the right dimensions ?

Since frequency is inversly proportional to the wavelength any CAD machine would be able to adjust the programme accordingly.

I would assume a 3D model will not efficiently pass millimetre waves though, the finished product in plastic could however create a solid metal item by use of a sandcast.

 

[zorrin]

Since frequency is inversly proportional to the wavelength any CAD machine would be able to adjust the programme accordingly.

I would assume a 3D model will not efficiently pass millimetre waves though, the finished product in plastic could however create a solid metal item by use of a sandcast.

you mean that a cross multiplication is sufficient to go from 78-102 GHz to 18-26.5 GHz?

 

[Channel Hopper]

you mean that a cross multiplication is sufficient to go from 78-102 GHz to 18-26.5 GHz?

View attachment 143254

Yes, though you will need to round down the flange sizes to the next available Wr/WG number.

Waveguide Flange Sizes & Types

www.atmmicrowave.com

 

[zorrin]

Yes, though you will need to round down the flange sizes to the next available Wr/WG number.

Waveguide Flange Sizes & Types

www.atmmicrowave.com

I am surprised at the measurements for the 18-26 waveguide, the ratio is not 2 but 2.47



If I find a CNC machinist not too expensive I would make a piece to see but directly for the fixing of the GILAT lnbs.
For the feedhorn it's another story...

 

[zorrin]

No I did not mod the ports (yet)
I called that side port TX port but thats wrong , that port is orignaly closed by a plate .
The TX signal is fed-in through the back of the OMT , that port is 7 x 3 mm .
Both other ports , deep in the wave-guide , are the same , 8 x 2.5mm .
The RX port is going over into 11 x 4.5 mm .
Today I placed the 27.000 Xtal in the AN 8002 and made a blindscan with the LOF 18.250
Found EquTV 19.735 at H and V with 7.9 dB , seems the lnb is in circ mode ( no poplarizer attached)
Maybe caused by the shape of the lnb inlet ? it looks the signal is gonna twisted to the antenna probe .
Since I ruined the first AN 8004 (long time ago) I do have a spare RX body , so I will mod the port to rectangular and see what happens .
For those people wondering where to get the F connectors , I made them from angled types or from broken moteck rotor boards .

@Trust , look at the last page of the document I shared in my post 129.
Doesn't that remind you of anything?

@s-band had already put his finger on it

I think you should move on with your idea

 

[sat-tv-fan]

You can get Newsnet using an 8002, read what s-band wrote a few years ago:

Newsnet on Ka Band A

@sat-tv-fan This is how I started on Ka Ka with Prodelin/Viasat 1.2m Band B It's stil the cheapest way of getting Newsnet that I know of. In order of difficulty: 1 Get a Gilat AN8002 ODU (outdoor unit) form an old broadband set-up, remove the polariser. Use only the RX port (ignore the TX it...

www.satellites.co.uk

Your previous posts and profile suggest you have a TBS 6903 card, if so no difficult hardware mods are required. A larger dish may be needed but no harm trying..

Just been reading many of the replies which I didn't read at the time, all explained very clearly with great photos etc. I must have lost interest at the time as 2018 is the year my Dad died. Really appreciate the help to those involved