RadioBanter - Transmitter splatter

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Transmitter splatter

I find that the Radio Marti tx from Greenville (I think) on 6030 in the
evenings NAm time really plays havoc with BBCWS West Africa stream on
6035 which is on between 0300-0400 UTC. Officially, it's not a problem
because the two stations are broadcasting to totally different areas,
but that's my best chance to get BBC news since the Americas schedule
was eliminated. The other option, 7160, is plagued by Cuban bubble
jamming meant for Radio Republica which was there B05.

John Plimmer wrote:

Many of you are unaware that transmitters emit splatter.
A bad transmitter on the HF shortwave spectrum can emit 12 kilohertz of
splatter, that is 6 kilohertz of splatter either side of the centre
frequency. Since the shortwave band has a channel separation of only 5
kilohertz, that means that such a transmitter will obliterate and interfere
with signals either side of it on the 5 Khz separation.

Many of you may think that this interfering splatter is a result of poor
filters on your portable radio, but this is not so. Even very expensive
professional grade receivers with top of the line filters cannot get rid of
the splatter, as it is inherent and is on the band.

On the BCB AM mediumwave band the situation is even worse as many
transmitters will occupy a massive 30 Khz of space, severely disrupting
reception of other stations either side of it. It is possible to observe
such effects with the modern receivers that have spectrum scopes and also
the new breed of computer radio's such as the Winradio G3 series.

What can be done to remove this splatter? Very little I am afraid. One of
the only possibilities is to "phase" out the splatter with a device such as
the MFJ 1025/6, but these devices also have severe limitations and will not
work in every circumstance. Despite the glowing reports of some users with
these phaser's, they will only work if the station you want to phase out is
not too strong and also that the offending transmitter is at right angles to
the transmitter you are trying to receive.

Secondly, the phasing works better the lower down the frequency spectrum you
are, so on the mediumwave band it can be quite effective, but as you go up
the band the effect is less noticeable, so that by the time you get up to
about 6 Megahertz the phasers become almost ineffective.

The idea that antenna tuner's and antenna matching units will improve
matters relating to removing splatter is also wrong. They will not improve
that situation at all.

A better bet than tuner's and matching units for optimising signal strength
is the simple 9:1 or 4:1 magnetic matching transformer. The 9:1 is suitable
for the lower reaches of the spectrum and the 4:1 if you do more listening
above 10 Mhz. I am sure RHF will rush to give you lots of leads on these
very effective devices that do not require endless knob twiddling.

Transmitter splatter

In article ,
running dogg wrote:

I find that the Radio Marti tx from Greenville (I think) on 6030 in the
evenings NAm time really plays havoc with BBCWS West Africa stream on
6035 which is on between 0300-0400 UTC. Officially, it's not a problem
because the two stations are broadcasting to totally different areas,
but that's my best chance to get BBC news since the Americas schedule
was eliminated. The other option, 7160, is plagued by Cuban bubble
jamming meant for Radio Republica which was there B05.

Snip

For 6030 where I'm located the bubble jamming of Radio Marti from Cuba
is the problem. Radio Marti itself is not very strong at my location. I
have to listen upper sync selective sideband on 6035.

There is another station near but not on channel that plays havoc with
the BBC on 7160. The carrier off something like 1 KHz is the main
problem. I again have to listen sync selective sideband on 7160 or use
the notch filter.

--
Telamon
Ventura, California

Transmitter splatter

Telamon wrote:

In article ,
running dogg wrote:

I find that the Radio Marti tx from Greenville (I think) on 6030 in the
evenings NAm time really plays havoc with BBCWS West Africa stream on
6035 which is on between 0300-0400 UTC. Officially, it's not a problem
because the two stations are broadcasting to totally different areas,
but that's my best chance to get BBC news since the Americas schedule
was eliminated. The other option, 7160, is plagued by Cuban bubble
jamming meant for Radio Republica which was there B05.

Snip

For 6030 where I'm located the bubble jamming of Radio Marti from Cuba
is the problem. Radio Marti itself is not very strong at my location. I
have to listen upper sync selective sideband on 6035.

There is another station near but not on channel that plays havoc with
the BBC on 7160. The carrier off something like 1 KHz is the main
problem. I again have to listen sync selective sideband on 7160 or use
the notch filter.

My Yaesu is currently casters up so I'm forced to rely on my Degen 1102,
which simply isn't up to this sort of challenge. I had a little extra
dough left over this month after bills so I may pack the Yaesu up and
ship it to LA for repair.

Transmitter splatter

In article ,
Telamon wrote:

There is another station near but not on channel that plays havoc with
the BBC on 7160. The carrier off something like 1 KHz is the main
problem. I again have to listen sync selective sideband on 7160 or use
the notch filter.

I think that's the second harmonic of the TV color burst frequency.
A lot of consumer electronics run their micro/TV video chips on
7.15909, or 14.31818 MHz resonators or xtals. And since the damn things
are always on to "listen" for remote control commands...

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)

Transmitter splatter