Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #11   Report Post  
Old February 12th 18, 10:13 AM posted to uk.radio.amateur,rec.radio.amateur.homebrew
external usenet poster
 
First recorded activity by RadioBanter: Dec 2008
Posts: 375
Default 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.
  #12   Report Post  
Old February 12th 18, 10:57 AM posted to uk.radio.amateur,rec.radio.amateur.homebrew
external usenet poster
 
First recorded activity by RadioBanter: Sep 2015
Posts: 62
Default 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

  #13   Report Post  
Old February 12th 18, 11:35 AM posted to uk.radio.amateur,rec.radio.amateur.homebrew
external usenet poster
 
First recorded activity by RadioBanter: May 2017
Posts: 32
Default 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
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
[KB6NU] Is DMR a mass adoption phase winner in digital voice radio? KB6NU via rec.radio.amateur.moderated Admin Moderated 0 June 8th 16 05:15 PM
Computer Voice 'Glitch' on 4426 kHz [USB] @ 0610 UTC RHF Shortwave 0 May 19th 11 10:06 AM
FS: Digital VOM w/Computer Interface Bill Crocker Swap 0 November 27th 05 06:48 PM
How does digital voice work ? Tom Equipment 0 March 21st 04 04:32 PM
Digital voice on VHF marine? J999w Scanner 7 August 28th 03 06:08 PM


All times are GMT +1. The time now is 04:03 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017