Computer / radio isolation for digital (or even voice?)
 

Ian Jackson wrote:
In message , Lucifer
Morningstar writes
On Sat, 10 Feb 2018 11:21:17 +0000, Ian Jackson
wrote:

In message , Lucifer
Morningstar writes
On Fri, 9 Feb 2018 21:53:50 +0000, Ian Jackson
wrote:

In message , Gareth's Downstairs Computer
headstone255.but.not.these.five.words@yahoo. com writes



https://www.ebay.co.uk/itm/10x-Audio...Ohm-Europe-1-1
-EI14-Isolation-Transformer-Newest/172824007609?epid=2184088304&hash=ite
m283d1d13b9:g:d2EAAOSwDmtZlWH2

That's a fantastic price. I'm using a 600/600 ohm audio transformer to
isolate an earth-loop problem between the rig and the PC (extracting the
audio to feed into the sound card so I can get SSTV and DRM pictures
using MMSTV and Easypal).

I intend to try transmitting DVB-T on 438 Mhz but from what I have
read doing such will result in extra bandwidth due to sidebands.

I'm not sure how wide a single 'programme' DVB-T MUX is - but I suspect
it should fit inside the top end of the band. However, be aware of the
presence of certain non-standard repeater shifts (some up to 7.6MHz, I
think). Aren't some people trying live digital in the 1MHz extension of
2m? You need to check with the BATC.
http://www.batc.org.uk

I have DVB-T encoder modulator that can do 4 programs anywhere
from 30 to 960 Mhz.

But how wide is it when it carries only one 'programme'?

In theory it could omit carriers and transmit a narrower signal at
lower bitrate, but in practice "standard DVB-T transmitters" cannot
do this. I heard some amateurs produced modulators and alternative
firmware that can do e.g. a 2 MHz wide DVB-T signal.

Computer / radio isolation for digital (or even voice?)
 

"Ian Jackson" wrote in message
...
In message , Lucifer
Morningstar writes
On Sat, 10 Feb 2018 11:21:17 +0000, Ian Jackson
wrote:
In message , Lucifer
Morningstar writes
On Fri, 9 Feb 2018 21:53:50 +0000, Ian Jackson
wrote:
In message , Gareth's Downstairs Computer
headstone255.but.not.these.five.words@yahoo. com writes

https://www.ebay.co.uk/itm/10x-Audio...Ohm-Europe-1-1
-EI14-Isolation-Transformer-Newest/172824007609?epid=2184088304&hash=ite
m283d1d13b9:g:d2EAAOSwDmtZlWH2

That's a fantastic price. I'm using a 600/600 ohm audio transformer to
isolate an earth-loop problem between the rig and the PC (extracting
the
audio to feed into the sound card so I can get SSTV and DRM pictures
using MMSTV and Easypal).

I intend to try transmitting DVB-T on 438 Mhz but from what I have
read doing such will result in extra bandwidth due to sidebands.

I'm not sure how wide a single 'programme' DVB-T MUX is - but I suspect
it should fit inside the top end of the band. However, be aware of the
presence of certain non-standard repeater shifts (some up to 7.6MHz, I
think). Aren't some people trying live digital in the 1MHz extension of
2m? You need to check with the BATC.
http://www.batc.org.uk

I have DVB-T encoder modulator that can do 4 programs anywhere
from 30 to 960 Mhz.

But how wide is it when it carries only one 'programme'?

Its width will always be the same, even when switched off.
--
;-)
..
73 de Frank Turner-Smith G3VKI - mine's a pint.
..
http://turner-smith.uk

Computer / radio isolation for digital (or even voice?)
 

In message , FranK Turner-Smith G3VKI
writes
"Ian Jackson" wrote in message
...
In message , Lucifer
Morningstar writes



I have DVB-T encoder modulator that can do 4 programs anywhere
from 30 to 960 Mhz.

But how wide is it when it carries only one 'programme'?

Its width will always be the same, even when switched off.

You mean..... like....... 19.5"? That'll fit in the 70cm with room to
spare.
--
Ian