RadioBanter

RadioBanter (https://www.radiobanter.com/)
-   Shortwave (https://www.radiobanter.com/shortwave/)
-   -   balun and image (https://www.radiobanter.com/shortwave/94056-balun-image.html)

Charly May 6th 06 11:54 PM

balun and image
 

Dear all,

I just noticed tonight that, while listening what seemed to be Bucurest radio on
5900 kHz between 2100 and 2200 UTC, I had a strong image of Vatican Radio. This
Vatican radio transmition was on 5885 kHz, much stronger (closer, I'm in Paris
surburbs, France) than Bucarest. I disconnected my external antenna with balun,
and Vatican radio image disapeared from 5900 freq just listening off the whip.
Then I tried the antenna without the balun : the signal improvement is less than
with the balun, but at least I don't have the image...

The balun is home made, with a ferrite core than comes in two clippable parts
(used to reduce noise on wires) : so it is not a perfect balun for sure, but it
gives good results anyway for me...

I had the same thing occuring with my Sangean 909 and Sony SW100.

Can anyone explain that image phenomena to the humble radio beginner that I am ? :-)

Thanks in advance !!!

Charly

[email protected] May 7th 06 12:57 AM

balun and image
 
You would have to do some math to show you have an image. That is, an
image is very predictable if you know the IFs used in the radio.

Maybe your front end is overloaded, and going to the whip provides less
signal.

Generally if your radio input is a whip, the radio has a huge amount of
gain at the input to make up for the weak signal provided by the short
whip. Some radios have a switch that you set for either a whip, long
wire, or 50 ohm feed, adjusting impedance and gain accordingly.


Charly wrote:
Dear all,

I just noticed tonight that, while listening what seemed to be Bucurest radio on
5900 kHz between 2100 and 2200 UTC, I had a strong image of Vatican Radio. This
Vatican radio transmition was on 5885 kHz, much stronger (closer, I'm in Paris
surburbs, France) than Bucarest. I disconnected my external antenna with balun,
and Vatican radio image disapeared from 5900 freq just listening off the whip.
Then I tried the antenna without the balun : the signal improvement is less than
with the balun, but at least I don't have the image...

The balun is home made, with a ferrite core than comes in two clippable parts
(used to reduce noise on wires) : so it is not a perfect balun for sure, but it
gives good results anyway for me...

I had the same thing occuring with my Sangean 909 and Sony SW100.

Can anyone explain that image phenomena to the humble radio beginner that I am ? :-)

Thanks in advance !!!

Charly



Telamon May 7th 06 04:23 AM

balun and image
 
In article .com,
wrote:

Charly wrote:
Dear all,

I just noticed tonight that, while listening what seemed to be
Bucurest radio on 5900 kHz between 2100 and 2200 UTC, I had a
strong image of Vatican Radio. This Vatican radio transmition was
on 5885 kHz, much stronger (closer, I'm in Paris surburbs, France)
than Bucarest. I disconnected my external antenna with balun, and
Vatican radio image disapeared from 5900 freq just listening off
the whip. Then I tried the antenna without the balun : the signal
improvement is less than with the balun, but at least I don't have
the image...

The balun is home made, with a ferrite core than comes in two
clippable parts (used to reduce noise on wires) : so it is not a
perfect balun for sure, but it gives good results anyway for me...

I had the same thing occuring with my Sangean 909 and Sony SW100.

Can anyone explain that image phenomena to the humble radio
beginner that I am ? :-)

Thanks in advance !!!

You would have to do some math to show you have an image. That is, an
image is very predictable if you know the IFs used in the radio.

Maybe your front end is overloaded, and going to the whip provides
less signal.

Generally if your radio input is a whip, the radio has a huge amount
of gain at the input to make up for the weak signal provided by the
short whip. Some radios have a switch that you set for either a whip,
long wire, or 50 ohm feed, adjusting impedance and gain accordingly.


Yes, either it's an image or the radio front end is just overloaded
because if the BALUN is working right you will have stronger signals at
the radio input. If the radio has a sensitivity switch moving it to
local will do the same thing as removing the BALUN or just using the
whip on the radio.

--
Telamon
Ventura, California

RHF May 8th 06 10:30 PM

Balun Hook-Up and Signal Images - What is the Connection ?
 
Charly,

Balun Hook-Up and Signal Images - What is the Connection ?
http://groups.yahoo.com/group/Shortw...a/message/9411
http://groups.yahoo.com/group/Shortw...a/message/9393

So by itself the Radio using the built-in Whip Antenna
receives the 5900 kHz signal from Bucurest Radio - OK.

Questions - The Basic Wire Antenna :
1 - How are you connecting the External Wire Antenna to the Radio ?
2 - Are you connecting the Wire to the Radio
via the External Antenna Jack ?
3 - Are you connecting to the Wire to the Radio
by 'attaching' the Wire to the Whip Antenna ?
4 - Are you using a Ground Connecting with the Wire Antenna ?

Questions - The Balun and Wire Antenna :
1 - How are you connecting the Balun Wires (2) to the Radio ?
2 - Are you connecting the Balun Wires (2) to the Radio
via the External Antenna Jack ?
3 - Are you connecting to the Balun Wires (2) to the Radio
by 'attaching' the one Wire to the Whip Antenna and the
other Wire to where ?
4 - Are you using a Ground Connecting with the Balun ?


i want to know - iane ~ RHF
..
Shortwave Listener Antennas = http://tinyurl.com/ogvcf
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL Antenna Group = http://tinyurl.com/ogvcf

David May 8th 06 10:55 PM

Balun Hook-Up and Signal Images - What is the Connection ?
 
On 8 May 2006 14:30:27 -0700, "RHF"
wrote:

Charly,

Balun Hook-Up and Signal Images - What is the Connection ?
http://groups.yahoo.com/group/Shortw...a/message/9411
http://groups.yahoo.com/group/Shortw...a/message/9393

So by itself the Radio using the built-in Whip Antenna
receives the 5900 kHz signal from Bucurest Radio - OK.

Questions - The Basic Wire Antenna :
1 - How are you connecting the External Wire Antenna to the Radio ?
2 - Are you connecting the Wire to the Radio
via the External Antenna Jack ?
3 - Are you connecting to the Wire to the Radio
by 'attaching' the Wire to the Whip Antenna ?
4 - Are you using a Ground Connecting with the Wire Antenna ?

Questions - The Balun and Wire Antenna :
1 - How are you connecting the Balun Wires (2) to the Radio ?
2 - Are you connecting the Balun Wires (2) to the Radio
via the External Antenna Jack ?
3 - Are you connecting to the Balun Wires (2) to the Radio
by 'attaching' the one Wire to the Whip Antenna and the
other Wire to where ?
4 - Are you using a Ground Connecting with the Balun ?


i want to know - iane ~ RHF
.
Shortwave Listener Antennas = http://tinyurl.com/ogvcf
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL Antenna Group = http://tinyurl.com/ogvcf
.
The Shortwave Listener's Blessing :
SWL BLESSING = http://tinyurl.com/s2bjm
May You Never Tire of Listening to the Radio and Always
have Strong Signals and Noise Free Reception ~ RHF {ibid}
http://groups.yahoo.com/group/Shortw...a/message/9233
.
.

No mystery. Too much antenna. The radio is operating in the
non-linear portion of the curve.


Adam Zapple May 8th 06 11:21 PM

Balun Hook-Up and Signal Images - What is the Connection ?
 
"RHF" wrote in
oups.com:

Charly,

Balun Hook-Up and Signal Images - What is the Connection ?
http://groups.yahoo.com/group/Shortw...a/message/9411
http://groups.yahoo.com/group/Shortw...a/message/9393

So by itself the Radio using the built-in Whip Antenna
receives the 5900 kHz signal from Bucurest Radio - OK.

Questions - The Basic Wire Antenna :
1 - How are you connecting the External Wire Antenna to the Radio ?
2 - Are you connecting the Wire to the Radio
via the External Antenna Jack ?
3 - Are you connecting to the Wire to the Radio
by 'attaching' the Wire to the Whip Antenna ?
4 - Are you using a Ground Connecting with the Wire Antenna ?

Questions - The Balun and Wire Antenna :
1 - How are you connecting the Balun Wires (2) to the Radio ?
2 - Are you connecting the Balun Wires (2) to the Radio
via the External Antenna Jack ?
3 - Are you connecting to the Balun Wires (2) to the Radio
by 'attaching' the one Wire to the Whip Antenna and the
other Wire to where ?
4 - Are you using a Ground Connecting with the Balun ?


i want to know - iane ~ RHF




What radio? If it's one of them cheap plastic ones, you found the
problem.

AZ

Charly May 9th 06 09:59 AM

Balun Hook-Up and Signal Images - What is the Connection ?
 
Adam Zapple wrote:
What radio? If it's one of them cheap plastic ones, you found the
problem.


Hello Adam,

The radios were mentionned in the initial post :
- Sangean 909
- Sony SW100

Small plastic radios I agree. Cheap ?... Well this can be a subjective matter...

Charly


All times are GMT +1. The time now is 10:37 PM.

Powered by vBulletin® Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
RadioBanter.com