DATV/SSB PA For Pluto or Lime SDR
Re: DATV/SSB PA For Pluto or Lime SDR
Thanks Mike
Had not spotted those looks just what the doctor ordered
73
Nick
G1BVI
Had not spotted those looks just what the doctor ordered
73
Nick
G1BVI
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Re: DATV/SSB PA For Pluto or Lime SDR
Its nice to have no fan noise, they still need good ventilation though, I was told stuff like that had a fan assisted back-plane sort of arrangement rather than individual fans.
To get 28V you need to stack TWO of those '12V' PSU, ie, bottom one just tweaked as per mod to 14V, top one needs its 0 Volts isolating from the case, then join bottom +14 to top '0', the next +14 gives you the 28 WRT 0. The Electric RC flight people do it lots, in varying degrees of common sense.
Sooo much easier to buy one that's already at 28V....
Gareth
To get 28V you need to stack TWO of those '12V' PSU, ie, bottom one just tweaked as per mod to 14V, top one needs its 0 Volts isolating from the case, then join bottom +14 to top '0', the next +14 gives you the 28 WRT 0. The Electric RC flight people do it lots, in varying degrees of common sense.
Sooo much easier to buy one that's already at 28V....
Gareth
Re: DATV/SSB PA For Pluto or Lime SDR
Good point Gareth, they don't need much ventilation but they definitely need some. One of those USB fans for example or a stack of ex-broadcast DVB-T amplifier power supply fans along one side. You can get 28V too, rather than 27.2v. I posted a mod but they come in various designs so best understand the circuit before attempting it. it involves modifying the feedback which is via an optical isolator and don't mess with things elsewhere or it might become unstable and that's never a good thing with a power supply.
Mike
Mike
Re: DATV/SSB PA For Pluto or Lime SDR
I made the mistake of NOT isolating the Ov when I tried to combine them before and can testify to it causing fireworks !!!
73
Nick
73
Nick
Re: DATV/SSB PA For Pluto or Lime SDR
I've built a 32V PSU for my QO-100 amp using 3 of the HP server units modified to give 10.7v and the output isolating from ground on two of them. It works really well and the server units only cost £3 each. I had some shouldered spacers 3D printed to support the board where the grounded pillar had been, that and an M3 nylon bolt did the job perfectly.
73 Dave.
73 Dave.
...are you sure I can't use a pair of 813's?...
Re: DATV/SSB PA For Pluto or Lime SDR
Oh as an aside, if you replace the M3 screws securing the PCB with longer ones you produce some handy mounting points as there isn't anything use friendly as they arrive. You can either fit the longer screw ends through a chassis and secure with nuts or use hex spacers and use screws into those.
73 Dave
73 Dave
...are you sure I can't use a pair of 813's?...
Re: DATV/SSB PA For Pluto or Lime SDR
I secured the Nokia Amp to a heat sink 430 x 150
My PD4 is fitted with a lime mini which is fed int AMSAT UK driver amp to give 0dm out.
The Nokia amp is connected to a 28v 25A supply.
I measured the output power at just over 60w.
Verry impressive but it will need a fan to take the heat away,
See image (30db attenuator on output)
My PD4 is fitted with a lime mini which is fed int AMSAT UK driver amp to give 0dm out.
The Nokia amp is connected to a 28v 25A supply.
I measured the output power at just over 60w.
Verry impressive but it will need a fan to take the heat away,
See image (30db attenuator on output)