Norsat 3220 C band LNB Warning

[s-band]

It seems that the Norsat 3220 LNB has very little rejection of 22kHz on its supply (and maybe a general lack of rejection to any supply borne noise). I was testing LNBs on SES6, 40.5W using the beacon on 3947.5H. Switching to the Norsat as a reference I noticed sidebands on the beacon. At first I thought that either the synth had developed problems or data had been switched on the beacon. It turns out that I had left the 22kHz enabled and the Norsat is very susceptible to it. The 1st plot below is with the 22kHz on and the second is with the LNB powered from a lab PSU.



I wonder how many LNBs that are not 22kHz switched have a similar problem. Has anyone else noticed it?

Note to self (and others): Don't leave 22kHz switched on with non-switching LNBs.

 

[John]

@sband ....
Just going back to your earlier post Graham re: how you said your Norsat was letting 22KHz through etc i thought i would get my Norsat 3520 pll swapped out on the H/V only lump and have a bit of a comparison and noted this behaviour on the analyser.
Using 18v supply with 22KHz turned OFF there was good lock achieved ...... turn the 22KHz ON and the analyser instantly lost lock.
Using 15v supply with 22KHz ON did not affect anything and retained solid lock.

 

[John]

Here's a comparison of the Norsat 3520 pll lnb single feed against a Zinwell lnbf + AV-Comm barrel. The two are shown in the pic, make of it what you will.
Next i will substitute the Norsat for a JRC pll lnb lump for a comparison.

 

[John]

Here's a comparison of the Norsat 3520 pll lnb single feed against a Zinwell lnbf + AV-Comm barrel. The two are shown in the pic, make of it what you will.
Next i will substitute the Norsat for a JRC pll lnb lump for a comparison.

A little bit better image of the two scans, but not by much ..

 

[moonbase]

John,

Thank you for the test result, very interesting and showing the Zinwell to be a decent performer against the presumably more expensive Norsat?

The signals from 38E are linear (H/V), do you know if the steps in the AV-COMM polariser barrel impact on the signal quality and did you try the Zinwell on its own without being connected to the AV-COMM polariser barrel?

What is the contraption connected to the Norsat, the bit that sits between the Norsat and the coned scalar, is it a home brew concoction or is it something available off the shelf? It looks to be something like a W225 flange to tubular feed?

Thx

 

[John]

John,

Thank you for the test result, very interesting and showing the Zinwell to be a decent performer against the presumably more expensive Norsat?

The signals from 38E are linear (H/V), do you know if the steps in the AV-COMM polariser barrel impact on the signal quality and did you try the Zinwell on its own without being connected to the AV-COMM polariser barrel?

What is the contraption connected to the Norsat, the bit that sits between the Norsat and the coned scalar, is it a home brew concoction or is it something available off the shelf? It looks to be something like a W225 flange to tubular feed?

Thx

Bare with me D, i'm just in the garage knocking up a servo motor bracket to JRC pll lnb for testing tomorrow if it's not raining ......... i'll reveal all later when iv'e come in from playing.

 

[John]

Do you mean this thing D,

i thought you had a pucka ADL version of one of these ? .... they are available from SSS but are a bit pricey, i bought two from China for about £35 all in.
The barrel does not seem to introduce any appreciable loss and works really well with the Zinwell. I have a spare Zinwell that i will test on it's own on 38°East which will give us an idea of barrel loss when i get a minute.

 

[moonbase]

John,

Yes, thats the item. Could you please PM me the link to the Chinese supplier if you still have it available?
I do have the ADL version with both single LNB and dual LNB waveguides but that one you have pasted the picture of would be useful as a spare and for testing purposes.

Rgds

 

[John]

Try this one for a start, can't remember if this was the actual supplier i used though.

[Hot Item] C Band LNB Single Polarity Feedhorn

 

[John]

... Or this
Aliexpress.com : Buy Single Polarity Feed Horn For C Band LNBF from Reliable feed horn suppliers on Anhui Bowei Electronics Technology Co., Ltd.

 

[s-band]

... Or this
Aliexpress.com : Buy Single Polarity Feed Horn For C Band LNBF from Reliable feed horn suppliers on Anhui Bowei Electronics Technology Co., Ltd.

That looks like the one I got. hot sale good quality c band single polarity feedhorn-in Radio & TV Broadcast Equipments from Consumer Electronics on Aliexpress.com | Alibaba Group There are lot more instances from the same seller. c band lnbf - Shop Cheap c band lnbf from China c band lnbf Suppliers at Anhui Bowei Electronics Technology Co., Ltd. on Aliexpress.com I can't work out if they many are made at the same factory.
This search brings back the singles and dual feeds. Some have scalars for a few $ more.
Shop feedhorn online Gallery - Buy feedhorn for unbeatable low prices on AliExpress.com

The waveguide holes are not in the correct positions so a bit of bodgery is needed.

 

[moonbase]

John,

Thx for the links, I will get one ordered.

Rgds

 

[moonbase]

...The waveguide holes are not in the correct positions so a bit of bodgery is needed.

s-band,

Do you mean the bolt holes on the WR229 flange on the feed are out of alignment with those on a C band LNB?

Thx

 

[s-band]

s-band,

Do you mean the bolt holes on the WR229 flange on the feed are out of alignment with those on a C band LNB?

Thx

Yes. The feed flange holes are in the wrong positions for all proper WR229 flanges. John drilled them out, I used undersize bolts. I aligned the waveguides before tightening the bolts.

 

[John]

Yes. The feed flange holes are in the wrong positions for all proper WR229 flanges. John drilled them out, I used undersize bolts. I aligned the waveguides before tightening the bolts.

Yep, that's the important bit.
I like that site, you can spend many a happy hour just looking at all the bits and bobs

I aligned the waveguides before tightening the bolts.