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--- In loopantennas@..., "C. Beijersbergen"
<c.beijersbergen@...> wrote:

Recently I received the following message about the WL1030

loopantenna. It is an action with an offer for a set of difficult to
get components for the WL1030 antenna. The time window is this
weekend only, and the website is in dutch.

I am not involved, so no credits to me.

And I do not know how many sets are available, but you can always

try

Hi c.beijersbergen

Thanks for the advisory... regarding the offered "parts kit".... I
have just emailed my "intention to purchase" to the WL1030 email
address.

I used Babel Fish translator to read the site and it looks to me as
though this is an invitation to show interest in buying the parts.
The author of the offer will then place a bulk order. The unit cost
is stated as between 20 and 30 Euros depending on the number of
kits "ordered" by 1 July 07. I may be wrong but I think the "kit"
includes the newly designed PCB.

Site url: www.wl1030.com

This is just my take on the offer so anyone interested should visit
the site and draw their own conclusions. I for one would happily pay
30 Euros for the parts :-)

Fraser

Recently I received the following message about the WL1030 loopantenna. It is an action with an offer for a set of difficult to get components for the WL1030 antenna. The time window is this weekend only, and the website is in dutch.

I am not involved, so no credits to me.

And I do not know how many sets are available, but you can always try



Cor Beijersbergen van Henegouwen



Very recently an initiative started by a couple of radio enthusiast to help the HAM radio community with kits, containing the 'difficult' SMD components, coils and an amplifier pcb. They also support the builders with additional information, tips, pictures and the site has an active forum.

You can find their site (which is in Dutch) at: www.ng-ronde.nl/wl1030.

Oops. Yup, it does run off batteries. Just flip it over :))

-Mark

+++++++++++++++++++++++++++++++++

Wellbrook K9AY AM/MW Loop Antenna Is Back In Production

Wellbrook Product News


The renoun Wellbrook K9AY LF to 160m 4 Direction antenna is
back in production and is available at a new lower price.

The Wellbrook K9AY is the only commercial version to offer:

1) Remote control variable termination for optimum front to back ratio.

2) A low noise LF to 10MHz high gain pre-amplifier with a higher
IP2+80/90dBm and IP3+43dBm than any other commercial K9AY

and now you know - iane ~ RHF
.
.
. .

If anyone is interested,the patent # is 6529169,



you need to select "IMAGES",requires DJVUE plug-in.

This has schematics,with some shortcomings,and an in-depth
discussion of the underlying theory???
I'm interested in any comments from RF-Professionals.
Eb.

Building a Larger AM Loop Antenna for the Radiosophy
"HD100" Radio to capture more of the 1% Digital Signal
beyond the 10mv/m Contour of an AM Radio Station

{How To - Listening to "HD" Radio in the Fringe Areas}


ABOUT - The standard (OEM) little AM Loop Antenna
that comes with the Radiosophy "HD100" Radio and
is UN-TUNED : It Measures 4.25"x5" and has Six-Turns
(6-T). Using the "AM Loop Antenna Calculator"
-by- Bruce Carter

This would result in aproximately a 11.2 uH Inductance;
with 8 Feet of Wire in the Windings.


To create a bigger UN-TUNED AM Loop Antenna with
a Larger Signal Capture Area I used a 23" Hula
Hoop as a Tubular Form to hold the Turns of Wire.
Again using the on-line "AM Loop Antenna Calculator"

A Two Turn (2-T) Loop Antenna would be about 8.1 uH
of Inductance; with 12 Feet of Wire in the Windings.
- - - Experience with Loop Antennas has taught me
it is always better to start with a few 'extra' Turns
and 'trim-down' to find the better 'practical-answer'
to Loop Antenna "Sizing" mainly due to the Distributed
Capacitance of the Turns-of-Wire within the Loop Antenna
Element and other minor factors.


Empirical Testing {Trial-and-Error} Results :
[ With Respect to the smaller OEM AM Loop Antenna ]
* Five Turns (5-T) was "So So" about the same
as the smaller OEM AM Loop Antenna
* Four Turns (4-T) was Fair - slightly better
* Three Turns (3-T) was Good - much better
* Two Turns (4-T) was Fair - slightly better
So I settled on a Three Turn (3-T) Loop Antenna
Element. [ What Works . . . WORKS ! ]
According to the "AM Loop Antenna Calculator"

A Three Turn (3-T) Loop Antenna would give 16.3 uH
Inductance; with 18 Feet of Wire in the Windings.


The difference in size between the 'original'
OEM AM Loop Antenna and the new Hula Hoop AM
Loop Antenna -with respect to- Signal Capture
Area was 21 Sq In -vice- 415 Sq In about 1:20 :
The new Hulla Hoop AM Loop Antenna should
yield about 4 Times the Signal as the 'original'
and may be a 1 to 2 S-Unit improvement in the
Signal seen by the Radio.


iane ~ RHF
.
.
. .

You ask many questions in a short space.

I am a big fan of the straight, long/random wire antenna as a starting point. You can add loops, dipoles, active antennas, and other fancy antennas, but you should start with a simple long wire (really known as a "random wire") antenna, and enjoy listening to the radio right away.

Foremost, your long/random wire antenna will enable you to listen to the many interesting stations which are broadcasting from around the world without delay, while you construct other antennas, and test them against your initial random wire antenna, which will be your test or "control group."

Start with a simple wire antenna that has no coax cable feed line, but which uses a simple wire feed line - and locate the antenna outside your mobile home. Perhaps you could string one from one end of the home to the other, on poles attached to each end of the home, projecting higher than the roofline. Bring the feed line in through a window or some other crevasse, and start listening right away. Connect this to the high impedance terminal on your radio. You may or may not benefit from an RF ground wire connected to a copper/steel ground stake. (I do not get any benefit from one at my location, but things may be different at your lication.)

Next, construct that 40 foot long wire you mention, using coax cable feed line, and employ, perhaps, a 9:1 balun/transformer to match the high impedance of the random wire antenna element to the 50 ohm input on your receiver. Compare the performance of that second antenna to the initial random wire antenna you set up.

Then, perhaps, purchase one of the Kaito/Degen SWL loop antennas from one of our Chinese friends selling them on eBay for something like $16-$20 plus shipping, or, perhaps, from one of the American vendors for slightly more, depending on your socio-economic and political predilections, and threshold for economic pain. I have had good luck purchasing such items from Radios4you.com which charges a little more for these items, but has quick, reliable service. I have had good luck with from the Chinese guys on eBay, as well. There are other sellers, as well, many of whom are reliable, also. I am not picking favorites here.

I am not sure what you intend by "wrapping the coax cable around a homemade dog bone" -- Are you trying to make some sort of RF choke? If so, I would start out without it, and only add one if it becomes necessary to solve some kind of interference or noise problem you encounter. Usually, the most parsimonious solution is the best solution, and certainly the least expensive in terms of time and effort. However, post back if I am missing your point, and perhaps you could explain why your want to "wrap the coax" as you describe.

The purpose of a balun/transformer is to match the high impedance of the long/random wire to the lower 50 ohm input on your radio. You can use the high input connection and not use any impedance transformer, and see how it goes. You may get good reception with that simple arrangement.

Conversely, many suggest coax cable can reduce the pickup of environmental electronic and magnetic interference (noise) from household appliances, the home's electrical system, a television set, a light dimmer, florescent lights, and other sources of EMI/RFI in and around the home. The balun is a transformer to that converts the high impedance of the random wire down to the 50 ohm impedance of the radio input and matches the long wire impedance to the rated impedance of the coax cable (typically 50 or 75 ohms). Many times, however, you can feed the radio directly with a simple straight wire connected to the high impedance connector on the radio, and get listening with good results. You will have to determine whether or not you need to use coax cable in your case, depending on the noise and interference you receive at your listing location.

Keep it simple to start with, and compare other antenna designs to your original high impedance random wire antenna. If you do not like the notion of stringing your initial antenna from one end of your home to the other, you might just lay the initial antenna right on the roof (temporarily) as you compare it against other antennas that you install. As you get better antennas, take down the weaker ones, and continue building other ones, continually comparing them to what you know is a good performer.

You may find however, that one antenna works better one day than another, but on another day, it rates the other way around - depending on many often unquantifiable factors, including weather, propagation, directionality vis-a-vis the broadcast station you are listening to, various different frequencies, various different times of the day, and various unknown factors including good and bad luck.

Do not consider one antenna a weaker performer until you have compared it against another antenna(s) for several days under differing conditions at differing frequencies and differing times of the day and night. Only move to a different antenna design after much testing and consideration. I had up to seven antennas installed at my old home, and it amazed me that the different antennas were comparatively better and worse vis-a-vis the others under various differing conditions. Only after much testing and experimentation good one or two of them proved to be best, overall.

One final note concerning your intended long wire, which you say can only be 10 feet high. Make sure that it does not sag in the middle, and become a danger to yourself and others.

Just MY take. Best Regards. //// Richards ////
==============================================
bongo432002 wrote:

soon put up a longwire about 40'long and 10'high(best I can do)but I
would like to have them both just to have 2 antennas.

re..I'm going to wrap the coax around a

homemade 'dogbone'and

On 6/24/07, airchecklover <mdh@...> wrote:

Conclusion: Impressive. Fun. Wish it ran off batteries.

Mine has been running off the same 9V battery for years. (I don't use
it all that much.) You sure it doesn't take batteries?

-- Jay

On 6/24/07, Jon P <ny911truth@...> wrote:

regenerative amplification. Googling around to find out more,
however, I came across one article that basically pooh-poohed the
concept, at least for use with serious antennas and receivers:

(see the section titled "regeneration" toward the end)

Does anyone have any experience with this technology?

My Quantum QX Pro antenna has regen circuitry. I don't generally use
it a lot for MW, but there are occasions where nothing else in my
arsenal will do the job. I use the regen all the time when listening
for NDBs.

I don't know what that author's issue is with regen, but about the
only thing I'd agree with him on is that a bigger antenna that doesn't
need regen would be preferable to a smaller one that does. And if I
owned a small farm where I could lay out three or four Beverages, then
I probably wouldn't need regen. But I have a house with almost no yard
and regen with my tabletop antenna is a huge plus in my book.

I definitely have no idea what he was talking about with the comments
about a good receiver adjusting the gain and resulting in the system
being deaf. I have an excellent receiver renown for its front end
performance, and I know I benefit from having the regen.

If you don't need the great portability or the extended range of the
Kiwa pocket loop, you might want to take a look at the Quantum QX
antenna. I think it's likely to be a bit easier to use and will
certainly be easier as far as maximizing the nulls. The base unit will
be a bit cheaper too. Not that there's anything wrong with the Kiwa
stuff. Craig puts out an excellent product. But it's something else to
consider.

-- Jay

EMI/RFI antennas in general, not just loops, are designed for maximum
bandwidth and not efficiency. A capacitor tuned loop is the opposite end of
the spectrum from an amplified LF/MF/HF loop. An EMI test requires sweeping
broad frequency spans, and the less bandswitching, or tuning of the antenna
necessary the better, because that makes the test more efficient. The
efficiency and selectivity that are prized by someone trying to pull in a
weak signal in the presence of a strong one is just the opposite of the
efficiency desired by the EMI test engineer.

From: keith beesley <keith1226@...>
Reply-To: loopantennas@...
Date: Sun, 24 Jun 2007 01:56:34 -0700 (PDT)
To: loopantennas@...
Subject: Re: [loopantennas] Anyone know abt these LF-MW-HF loops?


Mark,

I've seen those military surplus loops on Ebay from
time to time. I'm no expert, but I don't see why they
wouldn't work on at least MW and SW if tuned to the
proper frequency. $600. is a little steep for me.

There's also a guy in Australia (PK's Loop Antennas)
who sells MW loop antennas for around USD$50. I have
one and it works very well; can pull in DX stations on
any average radio. Would probably work great with a
higher-end radio. He also makes LW loops and will
custom-build them for other frequency ranges if asked.

Keith

Does anyone know anything about the Kiwa Pocket Loop and Pocket
Regeneration Module? Note: this is NOT the same thing as the Kiwa MW
aircore loop.

see it here:

I'm especially interested in the regeneration module. I assume this
means regenerative *amplification*, yes? The copy on the Kiwa page
reads: "As the regeneration is increased the gain increases and the
received bandwidth decreases." This sounds like one sweeeeeeet
accessory for a loop. Apparently this is the "pocket" version of a
similar gizmo Craig Kiwa included with his big MW aircore loop. I'm
presently building a loop antenna and am tempted to experiment with
regenerative amplification. Googling around to find out more,
however, I came across one article that basically pooh-poohed the
concept, at least for use with serious antennas and receivers:

(see the section titled "regeneration" toward the end)

Does anyone have any experience with this technology?

- Jon

--- In loopantennas@..., "airchecklover" <mdh@...> wrote:

Broad Description:
(about) 24" diameter. Passive 6 position switch at base covering
150khz-30mhz. Mil-spec &/or calibrated to Standards. Described Uses:
magnetic field testing, direction finding or as a part of a noise
isolation kit. Some are old - military surplus from the 50's and

some

are being made new.

A couple makes/models:
Empire LP-105
PRD AT-1026/URM-85
CU-890/URM-85

I've seen the first two on eBay in the last few months selling
$200-$300. I can post the links if you want to see what I'm talking
about. Googling, there is scant little on these things. I found a
schematic for the CU-890/URM-85, a specialty RF shop that will rent

an

LP-105 for $200/wk or sell it used for $600 and indications of other
manufacturers still making these types of loops new.

What's with these things? Can they/why can't they be used for

LW/MW/SW

listening?

-Mark/airchecklover

I have used EMC loops, both passive and active in design. The passive
loops are OK for shortwave/Medium wave listening but can be
insensitive due to their broadband passive design.

The active broadband EMC loops use a lot of gain in the amplifier to
overcome the insensitivity of such a compact loop. In my experience
the noise floor of these active loops is quite high and thios makes
them a poor choice for DX work.

These types of loops are generally designed for near field operation
and were not designed with Shortwave DX work in mind. They will work
OK with Medium Wave due to the greater signal strengths of such
signals. The problem will then be Intermodulation products in the
active loop amplifier.

Just my 5 Cents worth.

Fraser

Mark,

I've seen those military surplus loops on Ebay from
time to time. I'm no expert, but I don't see why they
wouldn't work on at least MW and SW if tuned to the
proper frequency. $600. is a little steep for me.

There's also a guy in Australia (PK's Loop Antennas)
who sells MW loop antennas for around USD$50. I have
one and it works very well; can pull in DX stations on
any average radio. Would probably work great with a
higher-end radio. He also makes LW loops and will
custom-build them for other frequency ranges if asked.


Keith

Hi Everyone;

Just rcv'd a CCrane Twin-Ferrite for MW.

Preface: To get the most out of this unit, you have to like
'playing/fildding' with radio & Twin-Ferrite antenna position and T-F
tuning controls.

Test setup: CCrane Twin-Ferrite direct connected to a Kaito RP2100* in
the geographic middle of 2 million people (Milwaukee) in an old
neighborhood w/ power lines running N-S 40 ft from house (not good). I
can position the RP2100 just right to null 95% of noise coming from 40
feet to my west. I figure I'm also nulling radio signals from the east
and west. Hey, at least there's no noise.

6/23 /07 - High Noon ...

WLW AM700 50KW - Cinci to Milwaukee, abt 350 miles ... 2100 solo -
just a hint of a station. 2100 + T-F ... Hissy but very listenable &
understandable.

WJR AM760 50KW - Detroit to Milwaukee abt 275 miles ... 2100 solo - if
you strain you can make out what they're saying. 2100 + T-f ...
sounding like a Chicago 50KW station (90 miles) on a typical radio -
ie, some hiss/almost local.

WLS AM890 50KW - SW Chicago burb to Milwaukee abt 90 miles ... 2100
solo - hard to listen to and understand due to weaker signal than
other Chicago 50KW + nasty splatter from a 250watt local noisemaker at
860KHz (2 miles east) and a 5KW/30KHz wide HD hiss factory at 920KHz
(10 miles south - in line w/ WLS). 2100 + T-F ... Local. Yup. Local.

Conclusion: Impressive. Fun. Wish it ran off batteries.

Tips:
(1) Experiment with postioning radio, Twin-Ferrite antenna and
magnetic coupler if you're using it. You'll find a sweet spot if you
work at it.
(2) Moving T-F antenna closer to radio causes increased RF gain due to
coupling/feedback - putting the 2100 into silent overload at about 3
inches. Going with the sweet spot idea, I've found a position for the
antenna about 6 inches from the radio where I get some feedback (gain)
but not too much. Fiddling w/ the T-F tuning dial, I have a radio
signal Q-multiplier/notcher effect. I've found this can help peak a
weak adjacent station next to a splatter hog (see WLS above). I've
also found at night when several stations are competing, this
technique helps me peak or null the station I am aiming at.

Kaito RP2100* - I've compared the RP2100 on MW to a Sat 700, Sat 800,
Eton E1, GE SRII, GE SRIII. It's one of the best. I'll give an edge to
the SRII for sensitivity but the 2100 is tighter in narrow. RP2100
works better w/ T-F using direct connect.

-Mark/airchecklover

Broad Description:
(about) 24" diameter. Passive 6 position switch at base covering
150khz-30mhz. Mil-spec &/or calibrated to Standards. Described Uses:
magnetic field testing, direction finding or as a part of a noise
isolation kit. Some are old - military surplus from the 50's and some
are being made new.

A couple makes/models:
Empire LP-105
PRD AT-1026/URM-85
CU-890/URM-85

I've seen the first two on eBay in the last few months selling
$200-$300. I can post the links if you want to see what I'm talking
about. Googling, there is scant little on these things. I found a
schematic for the CU-890/URM-85, a specialty RF shop that will rent an
LP-105 for $200/wk or sell it used for $600 and indications of other
manufacturers still making these types of loops new.

What's with these things? Can they/why can't they be used for LW/MW/SW
listening?

-Mark/airchecklover

Greeting folks..first timer here.Would it be a good idea to use a loop
antenna for a Kenwood R-1000? It's going to be right in front of a
window facing south and I live in a mobile home.I'm going to sometime
soon put up a longwire about 40'long and 10'high(best I can do)but I
would like to have them both just to have 2 antennas.I also have a
DX-302 that was given to me.My choices are the
DE31MS..MFJ-1020C..MFJ-1020.I'm sure that ya'll know about the MFJ's
and you can google the DE31MS to see what it looks like.Money's an
issue here people and the wife is allready looking at me funny.100
bucks tops.About the longwire..I'm going to wrap the coax around a
homemade 'dogbone'and solder the shield to one wire and then the
centerline to the other then use some weather seal on the
connections.Would it be better to use a balum at the connection point
instead.Any feedback would be great.Thanks and hope to be a regular.

Don't you need _very_ well matched JFETs
to ensure drain current balance in that circuit?

Could this be avoided by giving each JFET source
an independent primary and 330 ohm resistor,
then linking the "centre-tap" with the capacitor?

If you were making a differential amplifier for instrumentation
purposes, yes. But in this application you are making a pair of source
followers, and the amount of error in using an unmatched pair in such an
application would hardly be noticeable. However, if you want to go to the
extreme of precisely matching (meaning "very well") devices down to 0.01%
you may feel free to do so.

Your second suggestion would be sufficient to overcome the adversity of
using unmatched FETs if you feel that it's necessary to be that exact. I
had thought of doing so, but the application is not that demanding since the
load impedance presented by the 2N5109 as seen through the transformer is
quite high.

Chris

,----------------------. High Performance Mixers and
/ What's all this &#92; Amplifiers for RF Communications
/ extinct stuff, anyhow? /
&#92; _______,--------------' Chris Trask / N7ZWY
_ |/ Principal Engineer
oo&#92; Sonoran Radio Research
(__)&#92; _ P.O. Box 25240
&#92; &#92; .' `. Tempe, Arizona 85285-5240
&#92; &#92; / &#92;
&#92; '" &#92; IEEE Senior Member #40274515
. ( ) &#92;
'-| )__| :. &#92; Email: christrask@...
| | | | &#92; '.
c__; c__; '-..'>.__

Graphics by Loek Frederiks

Hi Andy,
Yes, I agree. It makes sense that that efficiency would be a power in -
power out ratio. I was wondering how to compare it, though. E.g.,
what would be the efficiency of a plain old dipole up 30 feet in my
backyard? If the efficiency for that arrangement were, say, twice that
of a proposed rigid loop as calculated via the KI6GD program, I would
have second thoughts about spending the money to build such a loop (or I
would increase circumference up to 33 % or increase pipe diameter up to
the limit of my wallet.)
As I play with the program, using "reasonable" copper diameters and side
lengths (reasonable to me), I come up with efficiencies in the 25 to 40
% range.
Thanks,
Dave

--- In loopantennas@..., Andy <Andy.groups@...> wrote:

Also, what is the LoopCalc program comparing to when it states that a
certain configuration is , e.g., 51% efficient. Compared to a

standard

dipole?

I think all antenna efficiency programs use a resonant dipole

in free

space as the standard for antenna efficiency.

Actually, as far as efficiency is concerned, the reference is ideal or

no

loss. Efficiency, unlike gain, is not compared to a dipole or anything
else. 100% efficiency just means that all the power you feed into the
antenna, gets turned into radio waves and none is lost in the form of

heat

(resistance losses). 50% means half your input power is lost as heat

and

never gets out.

After dealing with the power lost to heat, then what's left over is

affected

by the antenna's gain ... which IS compared to a reference antenna

(dipole

or isotropic), and is a function of direction (since antenna gain is

all

about concentrating signals in some directions while sacrificing signal

in

other directions).

Andy

Also, what is the LoopCalc program comparing to when it states that a
certain configuration is , e.g., 51% efficient. Compared to a standard
dipole?

I think all antenna efficiency programs use a resonant dipole in free
space as the standard for antenna efficiency.

Actually, as far as efficiency is concerned, the reference is ideal or no
loss. Efficiency, unlike gain, is not compared to a dipole or anything
else. 100% efficiency just means that all the power you feed into the
antenna, gets turned into radio waves and none is lost in the form of heat
(resistance losses). 50% means half your input power is lost as heat and
never gets out.

After dealing with the power lost to heat, then what's left over is affected
by the antenna's gain ... which IS compared to a reference antenna (dipole
or isotropic), and is a function of direction (since antenna gain is all
about concentrating signals in some directions while sacrificing signal in
other directions).

Andy

Sam Morgan wrote:

using hamcalc
for 1.9mc
I come up with
a ~15 turn coil of RG-58
on a 3.5" coil form
using ~13' of coax
and the 80m loop needs to be shortened by ~ 13'

These lengths sound short to me.

I have had other replies that mentioned
using an open 1/4 wavelength stub
using RG-58 that would be ~ 128'
am I on track here?
would either way work?
is one way more narrow banded than the other?
meaning if I made this for 1.9mc
would it still work at 1.8 or 2.0mc?

I think a 1/4 wave shorted stub would be wider band than a half wave open stub. The open stub is also prone to arching from the high peak voltage at the open end during transmitting.