Hi all,
My uplink power to QO-100 is "just enough" I'm looking at adding another gain stage to the line up after the Pluto and Amsat driver board to give some bad day headway. I'm thinking either an RF2126 or a SKY65135, which is better for linearity or is there something better? Perhaps something before the Amsat board?
73 Dave.
Preferred device?
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Preferred device?
...are you sure I can't use a pair of 813's?... 
Re: Preferred device?
The other Amsat-UK board perhaps? The 100mW one with filtering, or is that what you have already?
Mike
Mike
Re: Preferred device?
Don't forget they do an upgrade kit for the original filtered S amp here
https://shop.amsat-uk.org/Gain_and_Powe ... 53037.aspx
John
https://shop.amsat-uk.org/Gain_and_Powe ... 53037.aspx
John
Re: Preferred device?
Mike, I only see the one amplifier on the Amsat website, which is the one being fed from the Pluto.
John, said amplifier has the upgrade fitted.
I do have a SPF5189Z board which I could place before the Amsat amp and turn down the Pluto output, perhaps I'll give that a try once home from my jollies.
73 Dave.
John, said amplifier has the upgrade fitted.
I do have a SPF5189Z board which I could place before the Amsat amp and turn down the Pluto output, perhaps I'll give that a try once home from my jollies.
73 Dave.
...are you sure I can't use a pair of 813's?...
Re: Preferred device?
I thought you needed more drive for the higher powered amplifier. AMSAT-UK did a more powerful amplifier which is what I thought you had.
https://amsat-uk.org/2020/02/10/5-watt- ... or-qo-100/
I looks like you already have the driver amp I was referring to, that gives about 100mW, a bit less probably for TV use. If you need more gain before that then one of the cheap modamp based 'low noise' amplifiers from AliExpress or Ebay might work, though you don't always get what you expected. Search for
50 MHz 3GHz low noise Amplifier - but that's probably no better than your SPF5189 board, if it is a genuine one, so try that first.
These come in various flavours, perhaps depending on what device or more likely the optimism of the seller on performance. There are some nice metal cased ones for a little more money.
If on the other hand it is the 100mW that is not enough, then you probably need a TQP3M9103 based board or even just use the first stage of one of these https://www.ebay.co.uk/itm/144715581769 amplifiers from Poland. The once described as Stereo https://www.ebay.co.uk/itm/204089169154 has two on the board. Even though many of these amplifiers won't play well on 2.4 GHz their driver units will and as a bonus, may work at reduced output running from 12V.
It might help if you told us what your existing amplifier is and why it is only just enough drive because there may be other ways to boost the gain a bit. For example by changing the bias or 'cough' by removing the filter.
Mike
https://amsat-uk.org/2020/02/10/5-watt- ... or-qo-100/
I looks like you already have the driver amp I was referring to, that gives about 100mW, a bit less probably for TV use. If you need more gain before that then one of the cheap modamp based 'low noise' amplifiers from AliExpress or Ebay might work, though you don't always get what you expected. Search for
50 MHz 3GHz low noise Amplifier - but that's probably no better than your SPF5189 board, if it is a genuine one, so try that first.
These come in various flavours, perhaps depending on what device or more likely the optimism of the seller on performance. There are some nice metal cased ones for a little more money.
If on the other hand it is the 100mW that is not enough, then you probably need a TQP3M9103 based board or even just use the first stage of one of these https://www.ebay.co.uk/itm/144715581769 amplifiers from Poland. The once described as Stereo https://www.ebay.co.uk/itm/204089169154 has two on the board. Even though many of these amplifiers won't play well on 2.4 GHz their driver units will and as a bonus, may work at reduced output running from 12V.
It might help if you told us what your existing amplifier is and why it is only just enough drive because there may be other ways to boost the gain a bit. For example by changing the bias or 'cough' by removing the filter.
Mike