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Old September 4th 06, 07:02 PM posted to rec.radio.shortwave
Telamon Telamon is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 4,494
Default Antenna blues, so far my Sony AN-1 wins!

In article . com,
"Jeroen" wrote:

Hello All,

Thanks for your replies. Here some reactions from my side:

I used an AN-1 in a concrete apartment for a year and it worked well
after I had made a change to it. Unmodified, it was quiet, didn't hurt
the signals but it didn't seem to have much gain. I added a thin
hustler 2 meter 5/8 whip to the end of the AN-1 whip (about 4 feet as I
recall) and that improved it consiserably. I think that Sony was
worried about generating spurious in high-signal areas like Europe and
used very a conservative amplifier. Adding a length to the whip in
weak-signal areas had no bad effects.


I did this as well, I do live in Europe (Holland) and it increased the
noise heavily, making it not really usefull for me.

Small active loop antennas are pricey but are most likely the best in
town choice.


Unfortunally, no money for that :\

To get an idea how this type of antenna will work in your location you
could build a passive loop at small cost using just coax cable.


This is what I am going to do. Aftre some digging around I will go for
copper tubing however, as on one site I found that on lower frequencies
thicker copper will do better then the thinner one advised in the
article I gave the URL for.

I'm looking forward to building somehting of my own though! And I'll
probably experiment afterwards to improve the results. Can't wait to
see wether it will outperform my AN-1 antenna.... The costs are, like
you said, minimal.

I'll post back when I have done some testing on my to-be magnetic loop


You don't have to use copper tubing. You can build the antenna using
just the coax.

If you build a 40 foot loop you would build it like this:
1. Cut a piece of coax 40 feet long.
2. Cut the shield only at 20 feet separate the shield about an inch.
3. Bring the ends of the loop together connecting the shields and center
conductor on one end.
4. Connect the shield of the lead-in coax shield to the shields of the
loop and the remaining free center conductor of the loop to the center
conductor of the lead-in coax.

The loop will be somewhat unbalanced but should work pretty good. You
can improve the balance of the loop by using a BALUN made of enamel
coated wire and a ferrite toroid core. If you use the BALUN you would
have both ends of the loop center conductors connected to a bifilar
winding on the core of a few turns where the other end of the winding is
connected to the lead-in center conductor and common ground made of both
end of the loop shields and the lead-in shield. All this should only
cost under $50 dollars.

--
Telamon
Ventura, California