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In a message dated 20/05/2007 16:39:19 GMT Daylight Time,
ewdawso_1@... writes:

I am in the parts gathering stage to building my first loop. I have
picked up a 4 section tuning capacitor 280 uuf per section. I am not
sure if I should connect each section in series and connect the antenna
to the first ant last section or is there a better way to wire this.
Thanks Ed Dawson


---------------------------------------------------

Hi Ed

If you wire all your capacitor sections in series you'll reduce your maximum
capacitance to 70pF, capacitors in series act in a similar fashion to
resistors in parallel.

If you want to increase capacitance you need to wire them in parallel.

If, as sometimes happen, the capacitors share a common ground terminal then
wiring them in series wouldn't be an option anyway.

How to wire them depends on the loop and the frequency range you want to
cover but a reasonable general solution for experimantation might be to wire one
section across the loop and then wire a switch so as to add the other
sections in parallel one at a time.
This will give you full range swings of 0 to 280, 0 to 560, 0 to 840, and 0
to 1120, which is quite a range.

Note that the "0" in each case is theoretical only, in practice there will
always be some residual capacitance at the minimum setting, that will again
increase as more sections are added in parallel.

regards

Nigel
GM8PZR

--- In loopantennas@..., "Fraser" <fraser.castle@...> wrote:

I had a search on ebay but could not find it, can you please give me
some further details or send me the link?

Thanks and best wishes from Australia!

Michael S

It's on ebay.com

Look here:


1925_W0QQitemZ180117646543QQihZ008QQcategoryZ38033QQssPageNameZWDVWQQrdZ
1QQcmdZViewItem

Fraser

That URL broke up and I couldn't seem to mend it. But here's what one
looks like:

Paul Norman [Seattle, Left Coast]

I had a search on ebay but could not find it, can you please give me
some further details or send me the link?

Thanks and best wishes from Australia!

Michael S

It's on ebay.com

Look here:


1925_W0QQitemZ180117646543QQihZ008QQcategoryZ38033QQssPageNameZWDVWQQrdZ
1QQcmdZViewItem

Fraser

--- In loopantennas@..., "portstevos" <portstevos@...> wrote:

--- In loopantennas@..., "Richard Zolla" <N8NKN@> wrote:

Loops have been around for quite a while.
Check out the "Bodine Loop" on Ebay.

N6NKN

I had a search on ebay but could not find it, can you please give me
some further details or send me the link?

Thanks and best wishes from Australia!

Michael S

I couldn't find it on ebay either. But Google yielded this charming item:

(Bottom left, c. 1926)

Regards, Paul Norman (Left Coast)

--- In loopantennas@..., "Richard Zolla" <N8NKN@...> wrote:

Loops have been around for quite a while.
Check out the "Bodine Loop" on Ebay.

N6NKN

I had a search on ebay but could not find it, can you please give me
some further details or send me the link?

Thanks and best wishes from Australia!

Michael S

Loops have been around for quite a while.
Check out the "Bodine Loop" on Ebay.

N6NKN

I measured the noise
(actually, noted it) out to about 15 feet while walking around with a
portable radio.

This discussion about noise reminds me of the really nasty noise problems I
finally overcame. I needed clear reliable WWV reception for astronomical
observations (asteroid occultation timing). Tried more than a dozen
different antenna systems, including phased multi-elements. Each different
antenna system helped with only some aspect of the total noise problem and I
still couldn't satisfactorily eliminate the noise.

Strong -off frequency- interference, from multiple sources, was causing the
poor reception. I even tried different radios hoping for a better "front
end". No luck until I stumbled across the idea of putting resistors in the
loop. No doubt doing that "eats up" some of the desirable received signal,
but it also "knocks down" the interference to a lever that the receiver can
reject. Putting resistors opposite the feed point worked so well that I may
never build another antenna without using resistive loading.

If anyone is fighting a noise problem that seems to defy solution, they
might want to try incorporating carbon resistors into the design.



Doug Kniffen

--- Marc <marcsje@...> wrote:

ultraorthodoxmindstream schreef:

Hello , i am new to this group and this type of

hobby.

i know my yahoo id is kind of long , people call

me ("Ultra")

for short. I bought a grundig S350 short wave

radio.

I unpacked it and connected it , i recieved some

stations but i

started thinking , ( I think if i get a antenna ,

i can get better

reception and more stations ). So i thought of

ccraine inc.

I bought a ( Kaito KA33 ) loop antenna. My

question is,

1) Are These 2 Devices very copatable together or

should i buy another

anteena or short wave radio? Thank You ,

Sincerely Ultra.....

I have a Degen SW antenna. It has a clip to connect
to an antenna, so
it works, even if you don't have an antena in
connector ..

Marc

-- Ok , Thank You.....
--
Shortwave transmissions in English, Francais,
Nederlands, Deutsch, Suid-Afrikaans, Chinese, Dansk,
Urdu, Cantonese, Greek, Spanish, Portuguese, ...
Updated every 2-3 months.

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ultraorthodoxmindstream schreef:

Hello , i am new to this group and this type of hobby.

i know my yahoo id is kind of long , people call me ("Ultra")

for short. I bought a grundig S350 short wave radio.

I unpacked it and connected it , i recieved some stations but i
started thinking , ( I think if i get a antenna , i can get better
reception and more stations ). So i thought of ccraine inc.

I bought a ( Kaito KA33 ) loop antenna. My question is,

1) Are These 2 Devices very copatable together or should i buy another
anteena or short wave radio? Thank You , Sincerely Ultra.....

I have a Degen SW antenna. It has a clip to connect to an antenna, so it works, even if you don't have an antena in connector ..

Marc

--
--
Shortwave transmissions in English, Francais, Nederlands, Deutsch, Suid-Afrikaans, Chinese, Dansk, Urdu, Cantonese, Greek, Spanish, Portuguese, ...
Updated every 2-3 months.

Hello , i am new to this group and this type of hobby.

i know my yahoo id is kind of long , people call me ("Ultra")

for short. I bought a grundig S350 short wave radio.

I unpacked it and connected it , i recieved some stations but i

started thinking , ( I think if i get a antenna , i can get better

reception and more stations ). So i thought of ccraine inc.

I bought a ( Kaito KA33 ) loop antenna. My question is,

1) Are These 2 Devices very copatable together or should i buy another

anteena or short wave radio? Thank You , Sincerely Ultra.....

Oh yes!
You must be a Great genius, because I also was thinking about trying to use some kind of tepe to keep the small thing on the radio receiver... This happened a few hours ago, I mean immediatelly reading those lines of the poor man without a way to use it in a proper way....
(Just to keep up a nice smile.)
ami
Richards <jruing@...> wrote:
I agree, but I fugure that is why they invented electrical tape... or
maybe use duct tape... or whatever works. Photographers gaffers tape
is a good choice because it comes off without leaving residue. Maybe
masking or blue painter's tape...

Just MY take... /// Richar5ds ///
======================================================

Marc wrote:

The MW loop is a bit difficult to handle, since you need to put the
small ferrite on the radio, and it is too small and light to remain
there ...

---------------------------------
Food fight? Enjoy some healthy debate
in the Yahoo! Answers Food & Drink Q&A.

The RFI field from the average home extend much less then I had

thought. <<<<

Hi Will,
I'm not sure how much you were thinking it extended, but here I use a
figure of about 20 feet to be on the safe side. I measured the noise
(actually, noted it) out to about 15 feet while walking around with a
portable radio. I have also tried to catalog and describe each noise for
each appliance or device because there were so many before I switched to
an outside loop and I wanted to know which plug to pull when necessary.
Dave

--- In loopantennas@..., "gfreport1" <gfreport@...> wrote:

--- In loopantennas@..., Ken Javor <ken.javor@> wrote:

But that discussion misses the point that the high impedance rfi you

are

avoiding with a shielded loop comes from nearby, in the near field,

while

the signal you are receiving is from far away. If the problem is two
intentional signals from far away, then the discussion is correct

and you

rely on frequency discrimination (tuned loop and/or tuned front-end)

to

discriminate between two closely spaced but different frequency

signals.

Finally, there is a very real value to shielding against the

electric field

of the very signal you are trying to receive - when you are

interested in

direction finding. The direction finding property of the loop is

related to

the magnetic, not electric field you are receiving.

Take a look at Dallas Lankford's measurements on "Measurements of
Some Antennas Signal to Man Made Noise Ratios" at:
<

Measurements%20Of%20Some%20Antennas%20Signal%20To%20Man%20Made%20Noise%20Ratios%20II.pdf>

The RFI field from the average home extend much less then I had thought.

Will

I agree, but I fugure that is why they invented electrical tape... or
maybe use duct tape... or whatever works. Photographers gaffers tape
is a good choice because it comes off without leaving residue. Maybe
masking or blue painter's tape...

Just MY take... /// Richar5ds ///
======================================================



Marc wrote:

Hi, folks!
I'd like to inform you about the underlying text also by this way, because it is a rather long letter.
The Peng Wang's address down went a little wrong, so I try to put it right here: aeriepx@...

Best Regards from Aimo

aimo ruoho <aimounto@...> wrote:
Hi,Folks!

I finally received the BCL-01A V2.0 HF ACTIVE LOOP ANTENNA yesterday after 3 weeks of waiting from China.
I purchased it through eBay on the 23rd of April from the seller Peng Wang (aeripx@...). Transaction amount:$99.00 including the postal etc. expences. ( €74,83 EUR from my VISA)
The producer is told to be a local Radio Amateur (un Radio Aficionado) in Jinan, China.

Well, I really was not able to know what to expect for, other than a really low price, but when I opened the very well secured package, I realized, that I was a winner, this time!
There was a rather short, but adequite USER MANUAL of 3 A5 pages with a photo and a BLOCK DIAGRAM OF BCL-01A V2.0; OPERATION INSTRUCTIONS FOR BCL-01A; FOR CHARGE; NOTES; SPECIFICATIONS; and PACKING LIST:
1. Amplifier Base Unit; 2. Loop Element ( 5MHz-19MHz); 3. Li-Ion Charger (8,4V); 4. 0.8M BNC (Q9) TO 3.5MM STEREO Cable; 5. 0.8M BNC (Q9) Cable; 6.Manual.

Finally into the machine itself: It really is a very directive device to be used with a radio receiver inside the house ( and of cource outside the house in a good weather! )
I especially was astonished at the capability of this rather small aluminium ( or Steel ) tube Loop ( 27.5cm/ 10,3" Diam.) to find the same stations from 153KHz to 30MHz as my other antennas on my roof! 5 of them: The RF Systems DX-One professional Mark II, DATONG AD-370 Active Dipole, a home made 120 cm Helically wound vertical, another longer Broom-Stick, "the Cuban imitation" ( a so-called Broom-Stick low noise ant.), and a 3-wire horizontal.

It must have a very good and capable amplifier to do that. I tested my roof antennas with the amplifier unit, and noticed a +40dB (9+40dB) increase of the signal, without any noticeable interference or noise of any kind! ( My receiver does not overload! )The best S/N ratio of my life!

If the much talked about Wellbrooks are sooooo much better antennas, I must be a poor old man and a stupid fool! (But they cost a lot more, do they not?!!!!!!!!) Remember: IT IS STUPID TO PAY MORE!

This Anglo-American Commonwealth!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!With all due respect, of course......................................................................

I have to tell you, that I am using one of the best professional U.S.-made receivers ever produced in that bold country, the famous TEN-TEC RX340 HF DSP RECEIVER!!!!! Congratulations to this innovative and nice nation of good people. I have some very good real friends over there.

Just this once, I think, this receiver has met THE antenna it seems to need! What will be the next stage of the marvellous flashes of genius of the brains of the Chinese inventors? --------Did I make this clear enough?

But, please, do not try to use the Power Unit to anything else, than to charge the battery inside of this Universal Vehicle! I tried to do it before I read the Instructions more thoroughly, but it only gave me a really bad whistling as a not expected gift!
So it only is a battetry charger, not a power unit to be used while listening! The main unit will work for 50 hours after fully charged.Try to find the best place to use it to find the Signals you are trying to listen.... I repeat: It is very directive!

I expect the German DX-specialists are soon going to tear this Marvel into parts and let us know all about it. They are so strict and thoughtful in their activities....Because they take their hobby so seriously, I think. And the Japanese, did you ever study their way of doing things so perfectly in what ever they do?

Anyway, please ask me more, if I really had you interested. I am going to try to be of use.
I must add, that I really am satisfied with my new toy! Really, it is not just a toy, but a very valuable helping hand to me and I think, to anyone interested and courageous enough to try it! Even more so than the famous other Loops from China, two of which I also have, namely the Degens, very cheap and respectable pieces of Active Loop Antennas from China!

I am waiting for the next future steps from that direction to enhance our marvellous hobby..............................................................................................................
You may disagree, for sure, but many others may agree with me and be happy with this Chinese Marvel.....................................?

Best Regards from Aimo, the Finnish veteran DX-listener spending his last days in the sunny and warm country of joy and wide smile, Spain.

---------------------------------
Don't be flakey. Get Yahoo! Mail for Mobile and
always stay connected to friends.

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---------------------------------
Moody friends. Drama queens. Your life? Nope! - their life, your story.
Play Sims Stories at Yahoo! Games.

[Non-text portions of this message have been removed]

But that discussion misses the point that the high impedance rfi you are
avoiding with a shielded loop comes from nearby, in the near field, while
the signal you are receiving is from far away. If the problem is two
intentional signals from far away, then the discussion is correct and you
rely on frequency discrimination (tuned loop and/or tuned front-end) to
discriminate between two closely spaced but different frequency signals.
Finally, there is a very real value to shielding against the electric field
of the very signal you are trying to receive - when you are interested in
direction finding. The direction finding property of the loop is related to
the magnetic, not electric field you are receiving.

From: "gfreport1" <gfreport@...>
Reply-To: loopantennas@...
Date: Fri, 18 May 2007 16:20:02 -0000
To: loopantennas@...
Subject: [loopantennas] Interesting page on RF noise, H versus V and why
loops may not be the answer


To quote frome tis page:

"We often hear things about high E-field response being bad and low
E-field response being good. Another thing we might hear is that loop
antennas are "magnetic", and the magnetic field is good for desired
signals while rejecting undesired noise. Along the same lines we
sometimes hear a "shielded loop" rejects noise while good signals pass
right through the shield walls. In fact none of these explanations are
technically accurate.

At distances more than 1/10th wavelength, a magnetic loop actually
responds better to electric fields than it does to magnetic fields! As
distances increase to 1/2 wavelength and beyond the electric and
magnetic fields even-out. The field impedance becomes fixed at the
impedance value (or field ratio) of freespace regardless what the
source or receiving antenna actually is. The graph below shows the
field ratio or field impedance of a small "magnetic" loop and a very
small dipole:"

<>

msznh schreef:

I'm thinking of buying a Kaito KA-31 shortwave active loop antenna but before I do I thought I'd ask if anyone has any experience with this antenna and if so, would you be good enough to share your opinions on it?

I have both the SW an AM loops, I bought them for 16,9$ from tku-china on ebay ..

They are worth the money, ie the sw loop is better than a self made 85cm loop (without ampli ..).

The MW loop is a bit difficult to handle, since you need to put the small ferrite on the radio, and it is too small and light to remain there ...


Marc

--
--
Shortwave transmissions in English, Francais, Nederlands, Deutsch, Suid-Afrikaans, Chinese, Dansk, Urdu, Cantonese, Greek, Spanish, Portuguese, ...
Updated every 2-3 months.

In a message dated 18/05/2007 03:22:03 GMT Daylight Time, msznh@...
writes:




I'm thinking of buying a Kaito KA-31 shortwave active loop antenna but
before I do I thought I'd ask if anyone has any experience with this
antenna and if so, would you be good enough to share your opinions on
it?






------------------------------------------
Hi Tom

These antennas are available under a variety of names and, from online
checks, the KA31 looks to be equivalent to the Degen DE31, covering shortwave
3.90MHz to 22MHz.

The DE31 has been superseded by the DE31MS which has the same shortwave
coverage but also covers Medium wave broadcast. The Kaito equivalent of this
looks to be the KA33.

You'll find discussion of the DE31MS in the archives here, as well as an
internal photo in the photos section.

I don't know what price you've seen the KA31 at but when I checked online
the Kaito versions seem to be selling for approx twice the price of the Degen
equivalents. A KA33 from a US seller was $49.99, a DE31MS on ebay, direct from
China was $22.90.

I bought one direct from China following the discussions here and it arrived
quickly.
One item missing from mine was the suction cup for window mounting. When I
commented I was told that was no longer supplied and that the advertising
literature would be changed.
I was quite surprised, it is a fairly fundamental part of the mounting kit
after all, but no real problem as it's a cheap enough item from any hardware
store.
The online literature doesn't look to have changed so perhaps they just
didn't want the extra expense of posting one, which I can understand.
So no big deal but thought I'd mention it just in case it is a universal
change.

In use it's a bit fiddly, tuning is very sharp on medium wave, so a bit of a
pain tuning around the band, although not so bad on shortwave, but very good
value at $23, and it works ok.
I personally wouldn't have wanted to pay $50 but take a look at the archives
and see what others thought of it.
If I was travelling a lot, or had problems putting up other antennas, I
would probably value it more but I bought mine mainly as a curiosity and just to
have a play with it.
Having said that, I'm not implying it's "just a toy", as a general purpose
antenna, within it's frequency range, it does a reasonable job.

regards

Nigel
GM8PZR

I'm thinking of buying a Kaito KA-31 shortwave active loop antenna but
before I do I thought I'd ask if anyone has any experience with this
antenna and if so, would you be good enough to share your opinions on
it?

Thanks,

Tom

Rob Moore <rmoore5@...> wrote: Actually Patrick,

Just shorting together the bottom points of the tube where it meets
the base, would cause it to be a shorted turn, which would then
totally disable the antenna, whether or not there were wires inside of


Hi Rob,

You are absolutely right; if the Al tube is a shield, it would then become a shorted shield which would short-out the magnetic field. I was just thinking of the reason why you still picked-up a signal although you shorted the Al tube; it is a short for DC but definitly not for AC.

Pat.



---------------------------------
Bored stiff? Loosen up...
Download and play hundreds of games for free on Yahoo! Games.

Hi Nigel,

Well, just put it down to intellectual curiosity. I want to
completely understand how the loop works. Having the loop be the
antenna is certainly one answer but that's not what I seem to see when
I look in mine. Short of de-potting a lot more of it (a slow time
consuming process!), cutting a small window in the top of the tube
seems like a good solution.

I'll let you know what I find.

Rob

Hi Rob

I really do thing this is a red herring.
I bought my 1530 2nd user with a radio and it was posted to the

first user

with the only protection being foam water pipe insulation

surrounding the

loop, on a par with the perf board construction I guess.
That might be fine sometimes but in this case the loop got a few

knocks and

ended up somewhat dented and distorted.
It still works fine but the point is I can't see how it would have

dented if

it was filled with the same potting material as used in the junction

box at

the base.
Not only that but I'm sure it would have been quite a bit heavier if

that

was the case.

I would expect to see potting material in the ends of the tubes, and

would

expect to see wires connecting the tube to the amp, but can't see

any reason to

assume the loop isn't the antenna.
That's the norm, so why should this one be any different?

regards

Nigel
GM8PZR






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