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Locked Re: Building my first loop

 

At 14:26 07/05/21, Digest Number 822 wrote:
Posted by: "gandalfg8@..." gandalfg8@... bibliophileuk
Date: Sun May 20, 2007 11:39 am ((PDT))
[snip]
If you want to increase capacitance you need to wire them in parallel.
[snip] 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.
But with a lot of not very useful overlap.

A better way, with one less switch, would be to
- wire the first section across the loop,
- parallel the second section with 280pF and
connect via a switch to the first section, and
- parallel the 3d and 4th sections and 840pF
and connect via a 2nd switch.

If you can find a 3-position progressive shorting
switch, so much the better.

This scheme will give you 3 non-overlapping ranges,
0 - C, C - 3C, and 3C - 7C, though in practice you
might choose to use slightly smaller fixed capacitors
so there is just a little overlap between ranges.

The reason for adding sections 3 and 4 as one range
is that otherwise the tuning rate would be very slow
on the lowest frequency range, because of the large
fixed capacitor and the fact that the tuning ratio is
the square root of the capacitor ratio.

[You can get another high range by switching two
sections in series to halve the values. Since the
minimum variable capacitance will be halved but not all
the strays will be, this will not be a 2f frequency range
but will be a 0 - C/2 top range with considerable overlap
with the 0 - C single-section range - unless you choose
to pad that with 140pF to become a C/2 - C range.]

Note that the "0" in each case is theoretical only, in practice there will
always be some residual capacitance at the minimum setting,
The minimum capacitance could be 20pF or more.
If you want to find out accurately and you have a frequency
counter or accurate receiver scale, it can be done by making
an oscillator using a fixed inductor and comparing the
variable against some small fixed capacitors.

Even if you don't have one which exactly matches the
minimum capacitance, you can get a calibration which
will allow you to calculate the minimum capacitance
from the maximum frequency.

that will again increase as more sections are added in parallel.
This no longer matters if the ranges are extended with fixed
capacitors, as the minimum capacitance and strays can be
incorporated into the value of the fixed capacitor. Only the
maximum frequency on the highest range is limited by the
minimum variable capacitance plus strays.


Regards, LenW
Locked Re: Building my first loop

 

At 14:26 07/05/21, Digest Number 822 wrote:
Posted by: "noswadplease" ewdawso_1@... noswadplease
Date: Sun May 20, 2007 8:38 am ((PDT))

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
Since the rotors are very likely on a common metal shaft,
probably you cannot connect more than 2 sections in series.

and connect the antenna to the first ant last section
or is there a better way to wire this.
Much depends on how big your loop is and what frequencies
you want to tune, which you haven't cared to tell us :-(
Locked Re: building my first loop

[email protected]
 

In a message dated 21/05/2007 16:01:10 GMT Daylight Time,
ewdawso_1@... writes:

Thanks Nigel and Jim, you both clarified for me what I need to do. I am
just a novice and am learning as I go. Ed Dawson



----------------------------------
Hi Ed

Glad to be of help.

Have fun, always the most important bit:-), and let us know how it goes.

regards

Nigel
GM8PZR
Locked Re: building my first loop

 

Thanks Nigel and Jim, you both clarified for me what I need to do. I am
just a novice and am learning as I go. Ed Dawson
Locked Re: Interesting Loop Antenna On Ebay

Richard Zolla
 

Michael,

Its a collectors item, and if you had a radio as old as the antenna
you might fine it a great part of your collection.

Rick





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

Ah!! Now I see how much it is going for, $99.00 but no bids yet
with only 17 hours to go! Does this mean that the antenna would not
be worth the $99.00 or does it mean that it would not be much of a
performing antenna compared to the latest designs??

Best wishes!

Michael S
----- Original Message -----
From: van lincoln
To: loopantennas@...
Sent: Monday, May 21, 2007 1:43 AM
Subject: Re: [loopantennas] Re: Interesting Loop Antenna On Ebay


here's the link:



van lincoln wd8aam

At 09:01 AM 5/20/2007 -0000, you wrote:
>--- 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)
>
>
>
>If you've got links, post them in the Links section!
>
>
>Post files here. If the file comes from a website, please put it
in the
Links rather than uploading the file.
>
>
>You can now view images at higher resolution in Photos. Upload
JPG and GIF
into Photos. Please convert BMP or TIF to JPG or GIF before
uploading.
>
>
>And please trim all this when replying!
>Yahoo! Groups Links
>
>
>
>




[Non-text portions of this message have been removed]
Locked Re: Interesting Loop Antenna On Ebay

Michael Stevenson
 

Ah!! Now I see how much it is going for, $99.00 but no bids yet with only 17 hours to go! Does this mean that the antenna would not be worth the $99.00 or does it mean that it would not be much of a performing antenna compared to the latest designs??

Best wishes!

Michael S

----- Original Message -----
From: van lincoln
To: loopantennas@...
Sent: Monday, May 21, 2007 1:43 AM
Subject: Re: [loopantennas] Re: Interesting Loop Antenna On Ebay


here's the link:



van lincoln wd8aam

At 09:01 AM 5/20/2007 -0000, you wrote:
>--- 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)
>
>
>
>If you've got links, post them in the Links section!
>
>
>Post files here. If the file comes from a website, please put it in the
Links rather than uploading the file.
>
>
>You can now view images at higher resolution in Photos. Upload JPG and GIF
into Photos. Please convert BMP or TIF to JPG or GIF before uploading.
>
>
>And please trim all this when replying!
>Yahoo! Groups Links
>
>
>
>
Locked Re: Interesting Loop Antenna On Ebay

Michael Stevenson
 

Ah yes, it is a huge oblong loop for medium wave, I wonder how it worked compared to the more conventional looking Lincoln loop beside it?

I was going to build an active medium wave loop antenna back in the early 1990s, I had all the materials ready to go and then we moved house, I lost the construction details and diagrams and some of the parts and for the life of me, I could not locate them or even come across the same article again, it was in Practical Wireless from the mid 1980s, I have searched everywhere through Practical Wireless archives but no luck!

Never mind! What cost was the Bodine loop going for?

Best wishes!

Michael S

----- Original Message -----
From: Paul Norman
To: loopantennas@...
Sent: Sunday, May 20, 2007 7:01 PM
Subject: [loopantennas] Re: Interesting Loop Antenna On Ebay


--- 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)
Locked Re: Building my first loop

Jim Dunstan
 

At 02:49 PM 5/20/2007 +0000, you wrote:

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,

You did not say what frequencies you are building the new loop. I am assuming the loop is for the MW frequencies ... eg 540-1700Khz.

In any event it sounds as if you don't quite understand how such a capacitor can be connected in series or parallel. So here goes:

Your capacitor will have 4 sections .... each section will have 1 or 2 connectors for each of the sections. Each of the connectors will represent 1 capacitor between it and the frame. In other words each capacitor section will be 280 uufd maximum between one tab and the frame.

Each tab will represent 280 uuf between it and the frame. If you connect 2 tabs in parallel then it will represent 560 uufd to the frame. If you connect 3 tabs in parallel you will have 840 uufd between them and the frame. If you connect all of them in parallel you will have 1120 uufd maximum to the frame.

Now it is possible to connect the in series .... to do so you will have to isolate the frame. Connect 2 tabs in parallel and the other 2 tabs in parallel and the maximum capacity between these pairs will be 280 uufd.

If your loop is designed for MW then a series connection will result in too little capacitance, you generally need a capacitor that will give you a maximum of 350 to 500 uufd.

Jim
Locked Re: Interesting Loop Antenna On Ebay

 

Some of the old Zenith floor model tube radios from the 40's used a loop antenna called the Wave Magnet.It was wound on a cardboard form.

----- Original Message -----
From: van lincoln
To: loopantennas@...
Sent: Sunday, May 20, 2007 10:43 AM
Subject: Re: [loopantennas] Re: Interesting Loop Antenna On Ebay


here's the link:



van lincoln wd8aam

At 09:01 AM 5/20/2007 -0000, you wrote:
>--- 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)
>
>
>
>If you've got links, post them in the Links section!
>
>
>Post files here. If the file comes from a website, please put it in the
Links rather than uploading the file.
>
>
>You can now view images at higher resolution in Photos. Upload JPG and GIF
into Photos. Please convert BMP or TIF to JPG or GIF before uploading.
>
>
>And please trim all this when replying!
>Yahoo! Groups Links
>
>
>
>
Locked Re: Interesting Loop Antenna On Ebay

 

looks well engineered even for today

Paul V Birke PEng
Guelph ON Canada

----- Original Message ----
From: van lincoln <vlincoln@...>
To: loopantennas@...
Sent: Sunday, May 20, 2007 11:43:55 AM
Subject: Re: [loopantennas] Re: Interesting Loop Antenna On Ebay













here's the link:



. com/2r57qp



van lincoln wd8aam



At 09:01 AM 5/20/2007 -0000, you wrote:

--- In loopantennas@ yahoogroups. com, "portstevos" <portstevos@ ...> wrote:
--- In loopantennas@ yahoogroups. com, "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:
eum.com/MISCACCY .HTM
(Bottom left, c. 1926)
Regards, Paul Norman (Left Coast)
If you've got links, post them in the Links section!
. yahoo.com/ group/loopantenn as/links
Post files here. If the file comes from a website, please put it in the
Links rather than uploading the file.

. yahoo.com/ group/loopantenn as/files
You can now view images at higher resolution in Photos. Upload JPG and GIF
into Photos. Please convert BMP or TIF to JPG or GIF before uploading.

. yahoo.com/ group/loopantenn as/photos
And please trim all this when replying!
Yahoo! Groups Links











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Locked Re: Interesting Loop Antenna On Ebay

 

That's how I found it in an instant awhile ago as well.

Don
Upland, CA



Richard Zolla wrote:

Strange, I just type in "Bodine loop" in the search and there it is!!!








--- In loopantennas@..., van lincoln <vlincoln@...> wrote:

here's the link:



van lincoln wd8aam


At 09:01 AM 5/20/2007 -0000, you wrote:

--- 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)



If you've got links, post them in the Links section!


Post files here. If the file comes from a website, please put it
in the

Links rather than uploading the file.



You can now view images at higher resolution in Photos. Upload JPG
and GIF

into Photos. Please convert BMP or TIF to JPG or GIF before
uploading.



And please trim all this when replying! Yahoo! Groups Links







If you've got links, post them in the Links section!


Post files here. If the file comes from a website, please put it in the Links rather than uploading the file.


You can now view images at higher resolution in Photos. Upload JPG and GIF into Photos. Please convert BMP or TIF to JPG or GIF before uploading.


And please trim all this when replying! Yahoo! Groups Links
Locked Re: Interesting Loop Antenna On Ebay

Richard Zolla
 

Strange, I just type in "Bodine loop" in the search and there it is!!!








--- In loopantennas@..., van lincoln <vlincoln@...> wrote:

here's the link:



van lincoln wd8aam


At 09:01 AM 5/20/2007 -0000, you wrote:
--- 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)



If you've got links, post them in the Links section!


Post files here. If the file comes from a website, please put it
in the
Links rather than uploading the file.


You can now view images at higher resolution in Photos. Upload JPG
and GIF
into Photos. Please convert BMP or TIF to JPG or GIF before
uploading.


And please trim all this when replying!
Yahoo! Groups Links
Locked Re: Interesting Loop Antenna On Ebay

van lincoln
 

here's the link:



van lincoln wd8aam


At 09:01 AM 5/20/2007 -0000, you wrote:
--- 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)



If you've got links, post them in the Links section!


Post files here. If the file comes from a website, please put it in the
Links rather than uploading the file.


You can now view images at higher resolution in Photos. Upload JPG and GIF
into Photos. Please convert BMP or TIF to JPG or GIF before uploading.


And please trim all this when replying!
Yahoo! Groups Links
Locked Building my first loop

 

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
Locked Re: Building my first loop

[email protected]
 

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
Locked Re: Interesting Loop Antenna On Ebay

Paul Norman
 

--- 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]
Locked Re: Interesting Loop Antenna On Ebay

Fraser
 

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
Locked Re: Interesting Loop Antenna On Ebay

Paul Norman
 

--- 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)
Locked Re: Interesting Loop Antenna On Ebay

portstevos
 

--- 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
Locked Interesting Loop Antenna On Ebay

Richard Zolla
 

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

N6NKN
17521 - 17540 of 21030