power from digilite on 23cm

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G3GJA
Posts: 337
Joined: Sun Nov 20, 2011 3:44 pm

Re: power from digilite on 23cm

Post by G3GJA » Sun Feb 05, 2012 6:21 pm

That's got me thinking.... I've got a spare HP laptop that has a 2GHz dual core cpu that might do the job but it will need either a boost inverter to get 19v @ 3.5A or probably easier to use a cheap mains inverter with the existing charger. Sat Rx is 12v as is LCD monitor, so it's feasible if I can find an USB WinTv.

I used a 330R in parallel with 100R for biasing the MSA-0886 from 10v. If you do a 70cm version be prepared to increase the post modulator pad.

I'll look at the 68pF mod. Mine is already closer to -60dBm but if I'll see if it is possble to lower it. I don't seem to remember seeing any difference between the Ultram and the HP 8573B SG.

Clive

M1EEV
Posts: 6
Joined: Wed Jan 25, 2012 4:43 pm

Re: power from digilite on 23cm

Post by M1EEV » Sun Feb 05, 2012 7:14 pm

Win tv pvr usb2 here but a bit expensive..
http://www.ebay.co.uk/itm/Hauppauge-Win ... 4160c800b4

9H1LO
Posts: 3
Joined: Wed Oct 05, 2011 7:26 pm

Re: power from digilite on 23cm

Post by 9H1LO » Thu Feb 09, 2012 11:26 am

how about this for o/p after the MAR-6 ?

http://www.9h1lo.net/ah1-v2.pdf

as soon as I get the DL board ready will try it

used to drive RA18H1213G to full o/p in analog/SSB

anyone daring to try it with DVB-S before me ?

G4EWJ
Posts: 1359
Joined: Wed Feb 17, 2010 10:11 am

Re: power from digilite on 23cm

Post by G4EWJ » Fri Feb 10, 2012 11:55 am

I think 200mW would be too much for DATV. My nominal 10mW PEP from the DigiLite drives an RA brick to about 10W and I don't think that will be very linear.

ZL2TAR's articles in the current CQ-TV show how to linearise the brick power output by increasing the standing current to about 700mA. After linearisation, he has 68mW in giving 22W out at the P1 point. I'd keep it a few dB below the P1 point to avoid regrowth.

On the diagram, the text at the top says 100uW input, but it says 10mW at the input itself.

Brian

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