Dear all,

I'm wondering wether I can use my Kaito KA31 active antenna (aka Degen DE31)
with a Sony SW100 radio... The manual says not to use any other antenna (at
least connected to the antenna jack) because of the 3v DC the radio supplies to
the AN100 antenna designed for this radio...

I don't want to blow up the antenna or the radio...

Any advice around there ???

Thanks in advance,

Charly

Hi Charly,

I don't have an answer, but a good source of information is here.

http://groups.yahoo.com/group/SonyICF-sw100/

I am certain someone there would have an answer.

Tom

I've never owned that particular small radio, but a ton of others. If I
was a betting man, I would bet your results would be poor using an
active antenna. Probably 8-10 feet of long wire is about all that
little radio can take before overloading the front end. More than that
and you'll hear images and junk all over the spectrum. An active
antenna would be much worse!

Try a few feet of simple wire and see what you get. Sell the active
antenna on eBay to finance the wire if you have to - he he. You'll
still have left over $$$.

-Tim
__________



Charly wrote:

Dear all,

I'm wondering wether I can use my Kaito KA31 active antenna (aka Degen
DE31) with a Sony SW100 radio... The manual says not to use any other
antenna (at least connected to the antenna jack) because of the 3v DC
the radio supplies to the AN100 antenna designed for this radio...

I don't want to blow up the antenna or the radio...

Any advice around there ???

Thanks in advance,

Charly

In article ,
Charly wrote:

Dear all,

I'm wondering wether I can use my Kaito KA31 active antenna (aka Degen DE31)
with a Sony SW100 radio... The manual says not to use any other antenna (at
least connected to the antenna jack) because of the 3v DC the radio supplies
to
the AN100 antenna designed for this radio...

I don't want to blow up the antenna or the radio...

Any advice around there ???

Thanks in advance,

Wire in a series capacitor to block the DC from the radio. A .1 uF 16V
should do fine.

--
Telamon
Ventura, California

The Sony SW100 (excellent radio) does indeed put a voltage on the antenna
jack. You will need to place a capacitor in series to block it. However, a
Sony AN-LP1 will work just fine but you have to turn it on manually with the
SW100.

"Charly" wrote in message
...
Tim wrote:
I've never owned that particular small radio, but a ton of others. If I
was a betting man, I would bet your results would be poor using an
active antenna. Probably 8-10 feet of long wire is about all that
little radio can take before overloading the front end. More than that
and you'll hear images and junk all over the spectrum. An active
antenna would be much worse!

Try a few feet of simple wire and see what you get. Sell the active
antenna on eBay to finance the wire if you have to - he he. You'll
still have left over $$$.

-Tim
__________

Thanks Tim for the advice...

I tried the wire and the active antenna with an ATS 909 : The wire does a
great
job when you can extend it in an "open area"... In some buildings or
hotels made
of steel+concrete you must put your wire outside... when you can open
windows !

With the small active loop, you just put it in front of the window...

In general, the active antenna (at least the one I own) outperform the
wire in
most cases... and it can also help keeping noise level a bit lower than
with a wire.

That's why I'm asking with the SW100...

Charly

SeeingEyeDog wrote:
The Sony SW100 (excellent radio) does indeed put a voltage on the antenna
jack. You will need to place a capacitor in series to block it. However, a
Sony AN-LP1 will work just fine but you have to turn it on manually with the
SW100.


Good morning,

Thanks for the advice...

I have another solution, using the adaptor that comes with my antenna : female
stereo jack to plug in the antenna at one end, two alligator clips on the other
end, 1 for the signal on the whip, 1 for the ground. I will connect the ground
to the "line-out" ground of the radio via a another jack.

It will be a starting point since I won't need to solder anything here...

I keep in mind the capacitor (I've read 470mF on the Yahoo SW100 group) for a
later use...

Charly

Hello again,

I just found this schematic of my active antenna :
http://www.drmrx.org/forum/attachmen...6&d=1130372787
(beware of wrapped URL)

I seems that (if I can read properly AND if I understand correctly the
schematic) the RF signal is delivered to the radio via C1 capacitor...

Another simpler schematic (made by the same person a little earlier) is here and
confirms this idea...

Can anyone give me a hint ?

Thanks !

Charly

I forgot to put here the link to the forum thread dealing with this antenna :
http://www.drmrx.org/forum/showthread.php?threadid=1210

I found a first answer here :
http://www.dai.ed.ac.uk/homes/cam/gadgets/SW100.html

Extract :
"If you want to use a Datong or other active/passive aerial plugged into the
external aerial socket then insert a .01uF capacitor in the centre lead to block
the power (this remark may not apply to the post-1997 SW100)."

As far as I know : 0.01 uF = 10 nF, so IF the lead-in center connector of the
DE/KA31 jack is protected by C1 in the schematic, then the antenna will work
with SW100... according to what is said on Chris Malcom's web page.

But is it ????

Charly

I will fill the thread all by myself :-) ...

I was wrong... Having a closer look on the schematics and pictures of the
internal parts of the antenna revealed that I was missunderstanding the
schematics... (I'm not an electronic guy...)

This schematics is concerning the loop amplifier circuit based at the bottom of
the loop :
http://www.drmrx.org/forum/attachmen...6&d=1130372787

Then we have the "battery box" here :
http://www.drmrx.org/forum/attachmen...1&d=1128874226
and also :
http://home.arcor.de/carsten.knuetter/DE31_inside.JPG
http://www.drmrx.org/forum/attachmen...9&d=1132431663

OK. I think I will open the box to check if there is really a capacitor and what
is its capacitance... Unless someone knows ???

Thanks

Charly