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At 12:06 pm ((PDT)) Sun May 27, 2007, Jim Dunstan wrote:

[big snip]
A tuned loop (about 3' in diam.) is my favorite receiving antenna when
living at the apartment on the 9th flr. I put mine on the balcony and tune
it remotely with 12 ft of 300 ohm twin lead fed into a Z-match antenna
tuner.

Does this mean there is no capacitor attached to the loop
and all tuning is done by the ATU? So the resistance of the
feeder is included in the loop resonance?

If so, you could get higher Q and hence more output by
tuning at the loop. OTOH, Q is one of those good things
one can have too much of. ;-)


Regards, LenW
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From Yahoo! Groups Help: ... trim all the irrelevant quoted text
out of your message (as a courtesy to the other members of
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Hey Everyone,

Excuses for those who saw this message as well on the
Shortwave-SWL-Antenna group; someone posted off list about this list
to me, so I just signed up here!


Who here has built a WL1030 and can help me answer these questions?

1) How do you like it? Its said its comparable to a Wellbrook, if you
know, can you comment on it?

2) Did you built one without the PSU? If so:
2a) What did you used for the 10v supply? (especially regarding their
comment it must be a "smooth 10v DC")
2b) Am I right to assume if you manually supply the amplifier 10v you
need to cut connection L1 - J3? And the 1/2Vcc is being supplied by
the extra/separated piece of circuit top-right on the diagram?

Anything else you would like to say about building this antenna?

Building circuits is rather new for me, but am keen to built this
antenna, as its both lots cheaper then a Wellbrook, and more fun to
make it yourself.

Thanks all,

Jeroen Kloppenburg

Jim, I don't even have to go out to the patio to make adjustments as my loop is mounted indoors where it picks up just as much noise as my whip antenna (36") and actually is capable of discriminating against some of it. I cover 8300-28900 khz on the smaller section of the dual capacitor, and with a small clip connector 4400-22000 khz both sections in parallel. Clipping in a 250 mmfd. mica gets me down to 3450 so I have the 80/75 meter band covered. Space constrictions in the apartment mean that my whip is not fully extended, so I get stronger sigs from the loop (the Sat 800 antenna systems are instantly switchable for comparison). I have a triple-spaced variable I could try if I wanted to transmit, but I found out a few years ago that sigs from the apartment were getting into the cable tv system and also into people's hearing aids {senior citizens' home} and as I will be 90 myself later this year I don't want to "make waves". Of course, reception is not what it used to
be but dividing my time between the computer and SWL fills in my hobby time. John M.

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At 07:16 PM 5/26/2007 -0700, you wrote:

I was a member of this group some time ago... somehow I became disconnected but the daily message content continued to be delivered to my e-mail address. While continuing to read the mail, I was struck by a construction note that discouraged the use of variable condensers for tuning purposes.because, as I interpreted it, the result would be weak signals. I decided to experience this phenomenon myself, so I have built a relatively crude loop, based on materials already at hand plus a 30 inch hula hoop. I was startled at how strong the signals are, because I had been led to believe that a loop delivered somewhat weaker signals along with a substantial loss in noise, in other words a better signal-to-noise ratio at the cost of a few S points on a tuning meter. I do have solid-state varactors on hand but I have been trying a selection of two-gang tuning condensers, mostly from surplus stores of around fifty years ago. I concluded that the weak link would be the connection
to the moving vanes (rotors) which is made via a ball-bearing race at one or both ends, and a spring brass or phosphor bronze contact finger resting against the metal frame. With 50 years of oxidation on the contactor, this could lead to vastly diminished performance by introducing resistance or diode action (or both) into the circuit. Therefore, I prepared the end of the contactor for soldering rather than a pressure fit. I rubbed it CAREFULLY (!) with a sand or emery board such as used in manicuring and tinned it with solder without damaging the rest of the structure. One end of the loop would be soldered there. The other point of contact ia where the grounded shaft rotates against the finger. To deal with the oxide there, I gave a couple of puffs of contact cleaner and worked the rotation about 20 times and hoped for the best. I also gave a couple of puffs to the ball race and to the shaft bearing at the back of the condenser. My loop is crude: a single turn of
insulated stranded hook-up wire fastened to the outer edge of the hula hoop with strips of masking tape about every 8 inches. The tuning conderser is mounted at the top of a piece of wood about 64" x 1 1/2 " , the loop mounted directly below with a couple of plastic ties, one end soldered to the contact finger, the other end soldered to the fixed plates (stators). For the pick-up loop, the experience of other people suggested 1/5 the diameter of the main loop, which would put me at 6". I happened to have on hand a circular antenna of the type that used to be supplied with TV sets using UHF tuners.... it has a diameter of 9" but that is what I am using for now. It is connected via RG58/U to the 52 ohm input of my Grundig Sattelit 800 and at the moment (0205 utc) I am listening to a strong signal from Habana, Cuba on 6180 khz. I know I have gone on and on somewhat, but I felt it worthwhile to dispel the notion that old tuning capacitors were no good and, who knows,
it might encourage some hesitant souls to try their luck at constructing a "crude" loop. John MacKay, VE7AFN.

Hi John,

If you are building a tuned loop for MF or HF receiving purposes the quality of the (air gap) variable capacitor is of minor consequence. In most cases the advantages of a tuned loop (even those using 30 year old variable capacitors with some rust in their joints) is a quantum leap ... and in most cases they are fed into or inductively coupled to modern high gain receivers. The quality of the capacitor becomes significant when the tuned circuit performance is more critical as for example when using a crystal radio receiver, or when feeding power to the loop antenna.

There are some tricks that can be used with old variable capacitors with questionable contact surfaces .... for example if you have a 2 gang (365 pfd per gang) capacitor you can connect them in series and isolate the frame from the circuit. This will give you a maximum of 182 pfd capacity .... but no questionable contact surfaces. If you have a 4 gang 500 pfd capacitor (as someone on this group mentioned) you could hook them into 2 parallel/ series pairs and have a full 500 pfd capacitor with no contact surface to deal with.

The added advantage is that the voltage capability is also doubled. If your dealing with power, then the capacitor problem is not only one of rusty joints but voltage capability .... since voltage across the capacitor gap rises very quickly as power is increased.

A tuned loop (about 3' in diam.) is my favorite receiving antenna when living at the apartment on the 9th flr. I put mine on the balcony and tune it remotely with 12 ft of 300 ohm twin lead fed into a Z-match antenna tuner. In order to rotate it I walk out on to the balcony and give it a twist hi hi . PS ... I have fed power into such a loop and have made several contacts ... but the design was intended for reception only. I am sure if I constructed the loop from larger diameter copper tubing instead of RG-58 coax and heavy duty home brew open wire feed line instead of 300 ohm twin lead, it would make a decent antenna for transmission as well.

Jim, VE3CI

I was a member of this group some time ago... somehow I became disconnected but the daily message content continued to be delivered to my e-mail address. While continuing to read the mail, I was struck by a construction note that discouraged the use of variable condensers for tuning purposes.because, as I interpreted it, the result would be weak signals. I decided to experience this phenomenon myself, so I have built a relatively crude loop, based on materials already at hand plus a 30 inch hula hoop. I was startled at how strong the signals are, because I had been led to believe that a loop delivered somewhat weaker signals along with a substantial loss in noise, in other words a better signal-to-noise ratio at the cost of a few S points on a tuning meter. I do have solid-state varactors on hand but I have been trying a selection of two-gang tuning condensers, mostly from surplus stores of around fifty years ago. I concluded that the weak link would be the connection
to the moving vanes (rotors) which is made via a ball-bearing race at one or both ends, and a spring brass or phosphor bronze contact finger resting against the metal frame. With 50 years of oxidation on the contactor, this could lead to vastly diminished performance by introducing resistance or diode action (or both) into the circuit. Therefore, I prepared the end of the contactor for soldering rather than a pressure fit. I rubbed it CAREFULLY (!) with a sand or emery board such as used in manicuring and tinned it with solder without damaging the rest of the structure. One end of the loop would be soldered there. The other point of contact ia where the grounded shaft rotates against the finger. To deal with the oxide there, I gave a couple of puffs of contact cleaner and worked the rotation about 20 times and hoped for the best. I also gave a couple of puffs to the ball race and to the shaft bearing at the back of the condenser. My loop is crude: a single turn of
insulated stranded hook-up wire fastened to the outer edge of the hula hoop with strips of masking tape about every 8 inches. The tuning conderser is mounted at the top of a piece of wood about 64" x 1 1/2 " , the loop mounted directly below with a couple of plastic ties, one end soldered to the contact finger, the other end soldered to the fixed plates (stators). For the pick-up loop, the experience of other people suggested 1/5 the diameter of the main loop, which would put me at 6". I happened to have on hand a circular antenna of the type that used to be supplied with TV sets using UHF tuners.... it has a diameter of 9" but that is what I am using for now. It is connected via RG58/U to the 52 ohm input of my Grundig Sattelit 800 and at the moment (0205 utc) I am listening to a strong signal from Habana, Cuba on 6180 khz. I know I have gone on and on somewhat, but I felt it worthwhile to dispel the notion that old tuning capacitors were no good and, who knows,
it might encourage some hesitant souls to try their luck at constructing a "crude" loop. John MacKay, VE7AFN.

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I am building the contol boxes for the K9AY Loop and am using
the FAR Circuits boards. I would love to hear from anyone who has built
them

73 John NS5Z

Automatic tuning could be made to work, but you will have to furnish a
pilot carrier for the coupler to know how to tune the loop. The SGC
"stealth kit" is basicly a green camouflaged loop and support with a
"smart-tuner". Information on the smart-tuner states that as soon as
you begin to transmit, the coupler senses your frequency and tunes the
antenna, so your transmitted signal is the pilot carrier. The signal
level required to tune the coupler/antenna may be quite small, perhaps
1.5 watts, but is required. Because the coupler could tune in just a
few seconds, you could, with a transfer switch, replace the receiver
with a signal generator on-frequency, tune the antenna to frequency,
and switch the antenna back to the receiver. The radiated signal from
1.5 watts injected into the antenna would not be easy to detect for
that brief period.

The other possibility that does work is to store presets for all
possible frequencies, and then simply go to those frequencies. We do
that with many of our commercial HF transmitters. A simple way to
implement this is to use a motor-driven capacitor with a "follow-pot"
to tune the antenna, and sense the position of the tuning capacitor.
Regards,
Paul
WA5LFY


--- In loopantennas@..., Jim Dunstan <jdunstan@...> wrote:

At 03:59 PM 5/25/2007 +0000, you wrote:

Hi, loop fans! I'm thinking of using an auto antenna tuner to match a
HF square loop's internal impetance with RG58. Is that possible?
Thanks in advance...

Yes, it is certainly possible. ATU's are primarily designed to tune

2-30

mhz and go into the auto tune mode when they receive an injection of
several watts of power from your xmitter. The larger the loop the more
efficient it will be as a radiator and receiver of radio signals.

The SGC

company advertises a 'Stealth' package based on an 80 ft wire loop

and an

ATU. The 80' wire is formed into a loop of a single, 2, or 3 turn
loop. They have lots of info on their site.

Jim, VE3CI

At 03:59 PM 5/25/2007 +0000, you wrote:

Hi, loop fans! I'm thinking of using an auto antenna tuner to match a
HF square loop's internal impetance with RG58. Is that possible?
Thanks in advance...

Yes, it is certainly possible. ATU's are primarily designed to tune 2-30 mhz and go into the auto tune mode when they receive an injection of several watts of power from your xmitter. The larger the loop the more efficient it will be as a radiator and receiver of radio signals. The SGC company advertises a 'Stealth' package based on an 80 ft wire loop and an ATU. The 80' wire is formed into a loop of a single, 2, or 3 turn loop. They have lots of info on their site.

Jim, VE3CI

Hi,

An automatic antenna tuner works matching the transmitted signal of the
transmitter to the antenna. If you are using it for this purpose it
will work well. I am using an LDG AT-200Pro autotuner for this purpose.
If you want to use it on a receiver only, it will not tune.

Hi, loop fans! I'm thinking of using an auto antenna tuner to match a
HF square loop's internal impetance with RG58. Is that possible?
Thanks in advance...

Hi Fraser,

I'll give them a try and see what's still available. I had already
ordered the "2nd half of the 90's" CD from the Medium Wave Journal,
which should include several of Andy's articles.

Thanks,
Rob

Hi Rob,

Shortwave Magazine became part of Radio User magazine which is a PW
Publishing product. Since the change it has not been very clear on
the website how you get copies of older SWM articles.

You can buy SWM articles via the following email address and phone
number:

Book & Back Issue Orders

books@...

Tel: 0870 224 7830
Fax: 0870 224 7850

At the back of the Radio User magazine another email address is
listed against the back issue charges (?5 per back issue magazine).

bookstore@...

Damn, Yahoo Groups Email address detector has hidden the email
addresses in my message.

Here they are again but I've used AT instead of @ so you will need to
change the email address accordingly before use.

Book & Back Issue Orders

booksATpwpublishing.ltd.uk

bookstoreATpwpublishing.ltd.uk

Fraser

--- In loopantennas@..., "Rob Moore" <rmoore5@...> wrote:

Hi John,

Unfortunately, there doesn't seem to be a way to order individual
articles (or even entire back issues) from SHortwave (Wireless?)
magazine when I looked on their website. Do you have a method?

Rob

Hi Rob,

Shortwave Magazine became part of Radio User magazine which is a PW
Publishing product. Since the change it has not been very clear on
the website how you get copies of older SWM articles.

You can buy SWM articles via the following email address and phone
number:

Book & Back Issue Orders

books@...

Tel: 0870 224 7830
Fax: 0870 224 7850

At the back of the Radio User magazine another email address is
listed against the back issue charges (?5 per back issue magazine).

bookstore@...

I ordered some photocopied articles from the 1980's and they cost me
?3 each inc P+P. Overseas orders attract a ?1 additional charge. Two
of the articles that I asked for were unavailable as the original
archive magazine had been lost.

Hope this helps

Fraseer

Hi John,

Unfortunately, there doesn't seem to be a way to order individual
articles (or even entire back issues) from SHortwave (Wireless?)
magazine when I looked on their website. Do you have a method?

Rob

--- In loopantennas@..., crabtreejr@... wrote:

Hello Rob et al

Andy Ikin did write a number of articles, as listed below. There

may have

been more.

A. Ikin, Active solution?, Short Wave Magazine, Oct 1996, pp 22, 23,

23 36

A. Ikin, Intermodulation - General Consideration for Active

Antennas, Short

Wave Magazine, Nov 1996, pp 28, 29
A. Ikin, Quieten it Down, Short Wave Magazine, Dec 1996, pp 32
(about low noise performance from long wire antennas)
A. Ikin, Broadband Loop Aerials (part 1), Medium Wave News, Jan

1998, pp

13-16
A. Ikin, Broadband Loop Aerials (part 2), Medium Wave News, Mar

1998, pp 9-12

A. Ikin, Receiving Loop Antennas, Short Wave Magazine, Oct 1998, pp

26-28

HTH and 73

John KC0G


In a message dated 5/22/07 6:19:49 PM Central Daylight Time,
rmoore5@... writes:

snip > Hi Nigel,

Actually, I'd be really interested to hear something about his
background. Did he work for a Radio company or has this always been a
hobby? When did he get the idea to make a better loop antenna? What
new things will be coming from his shop in the future? Would he be
willing to "Educate" some of us here on antenna design? It would be
fascinating.

snip >

Rob

***
See what's free at .

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

Hello Rob et al

Andy Ikin did write a number of articles, as listed below. There may have
been more.

A. Ikin, Active solution?, Short Wave Magazine, Oct 1996, pp 22, 23, 23 36
A. Ikin, Intermodulation - General Consideration for Active Antennas, Short
Wave Magazine, Nov 1996, pp 28, 29
A. Ikin, Quieten it Down, Short Wave Magazine, Dec 1996, pp 32
(about low noise performance from long wire antennas)
A. Ikin, Broadband Loop Aerials (part 1), Medium Wave News, Jan 1998, pp
13-16
A. Ikin, Broadband Loop Aerials (part 2), Medium Wave News, Mar 1998, pp 9-12
A. Ikin, Receiving Loop Antennas, Short Wave Magazine, Oct 1998, pp 26-28

HTH and 73

John KC0G


In a message dated 5/22/07 6:19:49 PM Central Daylight Time,
rmoore5@... writes:

snip > Hi Nigel,

Actually, I'd be really interested to hear something about his
background. Did he work for a Radio company or has this always been a
hobby? When did he get the idea to make a better loop antenna? What
new things will be coming from his shop in the future? Would he be
willing to "Educate" some of us here on antenna design? It would be
fascinating.

snip >

Rob

***
See what's free at .

Shucks!... All Andy did was repeat the info that is on his ALA1530 web
page.

Take that bit and some study of Dallas Lankford's material at...

<>

Hmmm... certainly not out of the realm of homebrew possibility.

73,

'Bear' NH7SR

Hi Nigel,

At least, as I said before I don't have to "operate" on the Aluminum.
I'm glad I held off for a few days thinking about it. Mea culpa!

Andy's a good guy and I understand why he doesn't want to talk much
about the amp, provide circuit diagrams, etc. He's spent a number of
years working on it and perfecting his antennas and according to the
reviews, has done a great job on it. The antennas are his livelihood
so why should he give out his secrets?

Actually, I'd be really interested to hear something about his
background. Did he work for a Radio company or has this always been a
hobby? When did he get the idea to make a better loop antenna? What
new things will be coming from his shop in the future? Would he be
willing to "Educate" some of us here on antenna design? It would be
fascinating.

Transformers can be calculated based on the core material, frequency
response, and impedance desired and then measured and tried to tweak
them up. Go for it!

Rob


--- In loopantennas@..., gandalfg8@... wrote:

Hi Rob

Being the totally wonderful and noble sort of chap that I am, I

shall resist

even the slightest temptation to say.....
"told yer so" :-)

Joking apart, whilst the content of Andy's emails don't surprise me,

that

you got them at all could be considered surprising given his earlier

comments.

Although I'm not daft enough to suppose he'll want to supply us with

all the

circuit information, well...I probably am daft enough but don't

suppose he

is:-), it is gratifying to think we might not be perceived as quite

such a

threat or adversaries after all.

As I said before, it's quite intriguing how much conjecture this

group,

myself included, has entered into regarding the make up of the

Wellbrook

antennas, and yet none of us has actually gone so far as breaking

apart our own

working 1530s etc.

Given that it wouldn't be all that difficult, I think that's a fair
indication that those of us who've got them appreciate them enough

that we just

prefer to use them.

Having said that, how many turns did you say was on that

transformer?:-)

regards

Nigel
GM8PZR








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

Here is a synopsis of messages I recently received from Andy Ikin,
they're pretty interesting and put to rest several questions that
people have about the ALA-1530. I stand corrected on the loop
configuration - The aluminum is the actual loop.

Rob

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

Dear Rob,

Further to your questions ref the above.

The loop is a single turn "un-shielded" coupled to a centre tapped
grounded phase reversal transformer at the input of a balanced
amplifier. The phase reversal transformer forces the two halves of the
loop to be at 180 degree phase difference. Hence the "Vertical"
E-field will cancel out and only the H field will induce a current
into the loop. The H-field will not induce any current into the loop,
when the plane of the loop is facing the lines of magnetic flux. Hence
the figure of 8 pattern.

Btw, during the development phase of the loop design many years ago,
several shielded versions were made; I was unable to measure any
difference rejection of local E-Field radiation. In fact the shield
reduced the HF sensitivity.

The ALA100 works in the same way. However, because the ALA100 has a
much larger aperture, then less amplifier gain is needed, hence a
lower amplifier noise floor.

Kind regards

Andy

In a message dated 22/05/2007 22:25:20 GMT Daylight Time,
rmoore5@... writes:




Here is a synopsis of messages I recently received from Andy Ikin,
they're pretty interesting and put to rest several questions that
people have about the ALA-1530. I stand corrected on the loop
configuration - The aluminum is the actual loop.






--------------------------------
Hi Rob

Being the totally wonderful and noble sort of chap that I am, I shall resist
even the slightest temptation to say.....
"told yer so" :-)

Joking apart, whilst the content of Andy's emails don't surprise me, that
you got them at all could be considered surprising given his earlier comments.

Although I'm not daft enough to suppose he'll want to supply us with all the
circuit information, well...I probably am daft enough but don't suppose he
is:-), it is gratifying to think we might not be perceived as quite such a
threat or adversaries after all.

As I said before, it's quite intriguing how much conjecture this group,
myself included, has entered into regarding the make up of the Wellbrook
antennas, and yet none of us has actually gone so far as breaking apart our own
working 1530s etc.

Given that it wouldn't be all that difficult, I think that's a fair
indication that those of us who've got them appreciate them enough that we just
prefer to use them.

Having said that, how many turns did you say was on that transformer?:-)

regards

Nigel
GM8PZR

At 3:19 pm ((PDT)) Mon May 21, 2007, Len Warner wrote:

[snip]
... high range ... two sections in series ... 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 [snip]

Oops: wouldn't be a 2f range anyway, forgot the sqrt.

Should read "... this will not be a 1.4f frequency range
but will be a 0 - C/2 top range with considerable overlap
with the 0 - C single-section range ...".