Transmit Line up which Works!

Latest News and Discussion about the use of the DATV transponder on Es'hail-2
G4uvz
Posts: 164
Joined: Sat Dec 09, 2017 10:30 am

Transmit Line up which Works!

Post by G4uvz » Fri Jun 28, 2019 12:31 pm

DRIVE AMPS FROM LIME TO SPECTRIAN

At last I have my system putting pictures through Oscar 100! My Spectrian produces around 50 watts and has the Ebay '8 watt' as a driver .The 8 watt amplifier as most know only produces 2- 2.5watts ....I am running this at 500mW to 1 watt max into the Spectrian. All this is located at the end of 15 M of low loss coax ..around 8dB at 2400.

At the other end, in the shack ..I have my Lime ..running from the Portsdown at a Lime gain between 62 and 74 ....this then feeds into a pair of Ebay 'Black Amplifiers' ( there seem to be 2 varients of this amp on the market some give around 12-15dB at 2400 the other gives nearer to 20dB) ..With Lime gain of 70 this will drive the Spectrian to about 20 watts .. As it is recommended to run the Lime as low as possible I use a second '8watt Wifi amp' in the shack with around 600mW output which in turn drives the 'ground station' to full power with Lime at 60-64 gain.

So in conclusion 2 off 8 Watt Wifi providing 13dB gain each. 2 off Ebay Black amps giving 15+dB gain each overall system gain 55-60dB minus 8dB cable loss

Hope that this is of help / interest G4UVZ

radiogareth
Posts: 317
Joined: Wed Jan 06, 2016 9:46 am

Re: Transmit Line up which Works!

Post by radiogareth » Fri Jun 28, 2019 7:47 pm

Interesting, I'm assuming that this is the Spectrain PA unit (with 2 devices) not the pre-driver?
Gareth

G4uvz
Posts: 164
Joined: Sat Dec 09, 2017 10:30 am

Re: Transmit Line up which Works!

Post by G4uvz » Fri Jun 28, 2019 9:21 pm

Spectrian is 3 device unit from Pyrojo on ebay

G8AGN
Posts: 21
Joined: Mon Mar 05, 2018 1:41 pm

Re: Transmit Line up which Works!

Post by G8AGN » Sat Jun 29, 2019 7:17 pm

Do you have a link to the eBay black box amplifiers please ?

Barry, G8AGN

G4uvz
Posts: 164
Joined: Sat Dec 09, 2017 10:30 am

Re: Transmit Line up which Works!

Post by G4uvz » Sun Jun 30, 2019 7:42 am

Hi Barry..a couple of options.....https://www.ebay.co.uk/itm/Low-Noise-Am ... SwLKhcNK~C
These are slightly lower gain but a good robust construction.

These https://www.ebay.co.uk/itm/2Pcs-Low-Noi ... 0005.m1851

Are obviously a bit more vulnerable ..and this model indicates lower gain at 2.4....as with all things Ebay,,,you can find what appears to be identical but gains turn out differently! What I can say is that cascade no problem and then feed into the big 8Watt (1-2 Watt amplifier) ..Adrian

G8AGN
Posts: 21
Joined: Mon Mar 05, 2018 1:41 pm

Re: Transmit Line up which Works!

Post by G8AGN » Mon Jul 01, 2019 6:44 am

Adrian

Many thanks for the links

73 Barry, G8AGN

g8lce
Posts: 74
Joined: Sun Dec 06, 2015 10:26 am

Re: Transmit Line up which Works!

Post by g8lce » Wed Jul 10, 2019 10:19 pm

G4UVZ, what do you use to modulate your setup?
I have tried a Lime mini with DATV Express from Windows 10 and also from a Portsdown. The nearest to working the way I want was the Portsdown using video and audio in through the usb device. I have tried streaming from vMix but that was too high a data rate so had breakup. The static testcard gets a bit boring after a while! Streaming DVB-S2 H265 at 250SR would probably be good but I cannot seem to sort that out...
I think 333SR is probably the highest I can go with my setup as the power level returning is then near the limit. 250SR seems to be too low a data rate unless I ditch the audio.
I would like to know the settings you find work for you. I have seen some good results from others with low SR but good video and audio but have not found the right settings myself.

Martin G8LCE

G4uvz
Posts: 164
Joined: Sat Dec 09, 2017 10:30 am

Re: Transmit Line up which Works!

Post by G4uvz » Fri Jul 12, 2019 7:07 pm

Hi Martin..I use the Lime with the Portsdown and it seems to work very well.

At an SR1000 and FEC up to 2/3 I can get through Oscar 100 with 40 watts and a 1.2 M dish

This was using the Pi Cam...£6 on Ebay! and a C290 Webcam for the audio.

There is a very useful table which helps to show what will and wont work ...

See attached Image
Attachments
Screenshot (68).png
Screenshot (68).png (276.27 KiB) Viewed 880 times
Screenshot (68).png
Screenshot (68).png (276.27 KiB) Viewed 880 times
Screenshot (68).png
Screenshot (68).png (276.27 KiB) Viewed 880 times

G4uvz
Posts: 164
Joined: Sat Dec 09, 2017 10:30 am

Re: Transmit Line up which Works!

Post by G4uvz » Fri Jul 12, 2019 7:09 pm

Hope that the above is helpfull ...sorry about the multiple copies...The pasting of images on this forum always catches me out!

g8lce
Posts: 74
Joined: Sun Dec 06, 2015 10:26 am

Re: Transmit Line up which Works!

Post by g8lce » Fri Jul 12, 2019 11:24 pm

Thanks for that. Here is the link to that page as well...

viewtopic.php?f=103&t=6070#p19583

Martin G8LCE

Post Reply

Return to “Es’hail-2 - DATV Transponder”