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UK Caravanning (uk.rec.caravanning) A forum for the discussion of caravanning undertaken by residents of the United Kingdom, whether in the UK or abroad. It encourages the interchange of views on the merits of models of caravan, makes of tow car, accessories, caravan sites, caravan clubs, and other related topics. The term caravan is to include trailer vans, motor caravans and trailer tents.

'Noisy' radio when listening on MW



 
 
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  #1 (permalink)  
Old July 3rd 09, 11:36 AM posted to uk.rec.caravanning
DartMan
external usenet poster
 
Posts: 9
Default 'Noisy' radio when listening on MW

When hooked up to the mains and wishing to listen to medium wave there
is considerable hum etc.
Can anyone suggest a suitable method of cancelling it? In the "good
old days", we merely fitted a suppressor into the 12v feed from the
car but I suspect it's a mains problem.
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  #2 (permalink)  
Old July 3rd 09, 11:44 AM posted to uk.rec.caravanning
DieSea
external usenet poster
 
Posts: 508
Default 'Noisy' radio when listening on MW


"DartMan" wrote in message
...
When hooked up to the mains and wishing to listen to medium wave there
is considerable hum etc.
Can anyone suggest a suitable method of cancelling it? In the "good
old days", we merely fitted a suppressor into the 12v feed from the
car but I suspect it's a mains problem.


Usually the caravan power supply / charger

I've got the same with my 'Van

Where's Harry ??

He'll have the answer

DieSea


  #3 (permalink)  
Old July 13th 09, 07:19 PM posted to uk.rec.caravanning
Harry Bloomfield[_2_]
external usenet poster
 
Posts: 278
Default 'Noisy' radio when listening on MW

After serious thinking DieSea wrote :
"DartMan" wrote in message
...
When hooked up to the mains and wishing to listen to medium wave there
is considerable hum etc.
Can anyone suggest a suitable method of cancelling it? In the "good
old days", we merely fitted a suppressor into the 12v feed from the
car but I suspect it's a mains problem.


Usually the caravan power supply / charger

I've got the same with my 'Van

Where's Harry ??

He'll have the answer


Sorry, the OP didn't get through here...

If he really meant a low pitched mains hum, then I would suggest it is
an old fashioned transformer type of charger rather than a more modern
switch mode type. As he says it only affects MW, I would suggest it
probably is a switch mode type and it is the switching of this breaking
through and causing a shriek on reception.

He didn't make clear whether it was a 12v powered radio or one running
from an internal battery, however assuming it is a switch mode type...

Check the metal case of the power supply is properly grounded to the
mains earth. Check the mains input of the power supply has a filter to
prevent the mains cabling from radiating noise.

Finally, if you think the noise could be radiating from the 12v
output...

Check the battery terminals are clean and tight and consider fitting
some ferrite toroids or rings on the 12v cables where the exit the PSU
- as close as possible.

You can get the ferrites from Maplins, if you just explain what you
want them for - you need two around 1" ID. Find some 20amp insulated
wire and wind as many turns as will fit tightly on each toroid, leaving
a space between start and finish. Connect one in series with positive,
one in series with the negative 12v.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk


  #4 (permalink)  
Old July 13th 09, 08:15 PM posted to uk.rec.caravanning
DieSea
external usenet poster
 
Posts: 508
Default 'Noisy' radio when listening on MW


"Harry Bloomfield" wrote in message
k...
After serious thinking DieSea wrote :
"DartMan" wrote in message
...
When hooked up to the mains and wishing to listen to medium wave there
is considerable hum etc.
Can anyone suggest a suitable method of cancelling it? In the "good
old days", we merely fitted a suppressor into the 12v feed from the
car but I suspect it's a mains problem.


Usually the caravan power supply / charger

I've got the same with my 'Van

Where's Harry ??

He'll have the answer


Sorry, the OP didn't get through here...

If he really meant a low pitched mains hum, then I would suggest it is an old
fashioned transformer type of charger rather than a more modern switch mode
type. As he says it only affects MW, I would suggest it probably is a switch
mode type and it is the switching of this breaking through and causing a shriek
on reception.

He didn't make clear whether it was a 12v powered radio or one running from an
internal battery, however assuming it is a switch mode type...

Check the metal case of the power supply is properly grounded to the mains
earth. Check the mains input of the power supply has a filter to prevent the
mains cabling from radiating noise.

Finally, if you think the noise could be radiating from the 12v output...

Check the battery terminals are clean and tight and consider fitting some
ferrite toroids or rings on the 12v cables where the exit the PSU - as close as
possible.

You can get the ferrites from Maplins, if you just explain what you want them
for - you need two around 1" ID. Find some 20amp insulated wire and wind as many
turns as will fit tightly on each toroid, leaving a space between start and
finish. Connect one in series with positive, one in series with the negative
12v.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk


I've got the same problem when the 'van is connected to the mains

My simple solution is to disconnect the 'van from the mains and the problems gone

The fitted radio in the 'van is useless any way

I haven't checked it out but I recon there's a problem with the antenna

DieSea


  #5 (permalink)  
Old July 13th 09, 08:38 PM posted to uk.rec.caravanning
Harry Bloomfield[_2_]
external usenet poster
 
Posts: 278
Default 'Noisy' radio when listening on MW

DieSea explained :

I've got the same problem when the 'van is connected to the mains

My simple solution is to disconnect the 'van from the mains and the problems
gone

The fitted radio in the 'van is useless any way

I haven't checked it out but I recon there's a problem with the antenna

DieSea


If with no antenna connect the noise is still there, then generally the
noise is getting in via the power cables.

If it is entering via the antenna, then the better the antenna and
further out into the 'clear' the less likely there will be noise
problems.

I don't get any such noise problems - I use the radio channels
delivered via satellite (Astra 28.2), combined with a small portable
radio.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk


 



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