Just bought a couple of these from Amazon for £5.87 each.
https://www.amazon.co.uk/gp/product/B07 ... UTF8&psc=1
I've tested one and it's PLL with a 25MHz crystal producing a nice T9 note.
I've taken it apart and taken pictures of its internals while I attempt to inject an external reference freq - will report back later how it turns out
Regards Tim
Another LNB PLL candidate
Re: Another LNB PLL candidate
Another LNB candidate is the AB LNB 01 'made by Inverto Factory', says made in China on the box, single and double versions available. Single £7.99 from Ebay. I bought one for the feed lens (easily detached) for use in a dual-band feed. Inside, its a PLL type with a 25MHz crystal.
73
73
Re: Another LNB PLL candidate
Looks good. I was going to have polarisation switching, but I am not going to bother now. The NB transponder is so strong the noise floor is visible even when cross polarised. By offsetting polarisation just a little, there is no impact to DATV and narrowband can still be copied, with no loss in SNR.
Mike
Mike
Re: Another LNB PLL candidate
So done a few experiments with some good news and bad news (at least so far).
Using it as standard with its 25MHz xtal the stability and phase noise is more than adequate for SSB.
Removing the crystal and injecting a low phase noise osc tunable from 23.6Mhz to 26.8Mhz results in an IF output of 1296 to 48Mhz respectively with a 10.5Ghz signal applied to the RF. The ref input gets multiplied by 390 as normal.
However when using an external reference the phase noise is very poor and not usable - despite trying various injection methods and levels. So still have some work to do on this.
At a minimum it looks as though changing the crystal would be an option to move the IF to a more suitable freq.
Changed the 25MHz xtal to a 24MHz which I had to hand and the IF moved up in freq as expected and with good phase noise - now if I could only inject my desired freq and get good phase noise.....
For the price, can't complain !
Regards Tim
Using it as standard with its 25MHz xtal the stability and phase noise is more than adequate for SSB.
Removing the crystal and injecting a low phase noise osc tunable from 23.6Mhz to 26.8Mhz results in an IF output of 1296 to 48Mhz respectively with a 10.5Ghz signal applied to the RF. The ref input gets multiplied by 390 as normal.
However when using an external reference the phase noise is very poor and not usable - despite trying various injection methods and levels. So still have some work to do on this.
At a minimum it looks as though changing the crystal would be an option to move the IF to a more suitable freq.
Changed the 25MHz xtal to a 24MHz which I had to hand and the IF moved up in freq as expected and with good phase noise - now if I could only inject my desired freq and get good phase noise.....
For the price, can't complain !
Regards Tim