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 Post subject: best sw antenna
PostPosted: Dec Fri 27, 2019 3:12 pm 
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Joined: Nov Thu 14, 2019 5:03 am
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Location: n.ca.
has anyone tried this antenna ? if so , did you like it ? did it work for ssb ? …………. thanks .. steve

MLA-30 Loop Antenna Active Receiving Antenna 100kHz-30MHz for Short Wave Radio

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 Post subject: Re: best sw antenna
PostPosted: Dec Fri 27, 2019 3:38 pm 
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Joined: Jul Mon 26, 2010 8:30 pm
Posts: 27290
Location: Annapolis, MD
Where is that blurb from? If it was something like EBay. then post a link.

In general, the best antenna is the one you have room for. The most important parameter is aperture...with higher frequencies--up to light-- it's typically the area--eg the "size of the hole in front of the camera". With the lower frequencies, it's length---eg the ubiquitous "long wire"

For something like the BC band, read any of the many threads here about loop antennas.

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"Measure voltage, but THINK current." --anon.


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 Post subject: Re: best sw antenna
PostPosted: Dec Fri 27, 2019 6:42 pm 
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Location: Mountains of Mourne. Ireland.
If I'm not mistaken the MLA-30 is based on...
Charles Wenzel's Active 3-30 MHz Hula-Loop Antenna for Shortwave...
http://www.techlib.com/electronics/antennas.html

Greg.


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 Post subject: Re: best sw antenna
PostPosted: Dec Fri 27, 2019 7:06 pm 
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Location: n.ca.
thank you for the link ………. im learning slowly . ham radio is just … 1) beam 2) power

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 Post subject: Re: best sw antenna
PostPosted: Dec Fri 27, 2019 8:25 pm 
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kzsteve wrote:
thank you for the link ………. im learning slowly . ham radio is just … 1) beam 2) power

Good insight...

Here is what I have always called the "antenna equation":
P(received) = P(transmitted) * (A1 * A2 / R^2)
A1 and A2 are the areas of the transmitting and receiving antennas, and R is the distance between them.

The equation is valid at the higher frequencies (including light) where antennas tend to be flat circles, ovals, etc.

For the lower frequencies, I'm sure there's an "equivalent area"

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"Measure voltage, but THINK current." --anon.


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 Post subject: Re: best sw antenna
PostPosted: Dec Sat 28, 2019 1:35 am 
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Joined: Nov Thu 14, 2019 5:03 am
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Location: n.ca.
insite ??? just mo power ………..

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 Post subject: Re: best sw antenna
PostPosted: Dec Sat 28, 2019 1:48 am 
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kzsteve wrote:
insite ??? just mo power ………..

?

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"Measure voltage, but THINK current." --anon.


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 Post subject: Re: best sw antenna
PostPosted: Dec Sat 28, 2019 4:15 am 
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Location: n.ca.
more power from amp

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 Post subject: Re: best sw antenna
PostPosted: Jan Sat 25, 2020 6:48 pm 
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Joined: Nov Thu 14, 2019 5:03 am
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Location: n.ca.
still checking on swl antenna . is there better than what I have ?

mla-30 @ 30' with rotor ………… any ideas appreciated ………… steve

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Last edited by kzsteve on Jan Sat 25, 2020 7:16 pm, edited 1 time in total.

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 Post subject: Re: best sw antenna
PostPosted: Jan Sat 25, 2020 6:48 pm 
Member

Joined: Nov Thu 14, 2019 5:03 am
Posts: 34
Location: n.ca.
still checking on swl antenna . is there better than what I have ?

mla-30 @ 30' with rotor ………… any ideas appreciated ………… steve

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 Post subject: Re: best sw antenna
PostPosted: Jan Sat 25, 2020 6:57 pm 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 10154
Location: Santa Rosa, CA
KZST Santa Rosa ???

Quote:
insite ??? just mo power ………..


Are you seeking a transmitting antenna? Loops and "active antennas" are usually used for receivers. MFJ sells transmitting loops, but beware the high voltages necessary with such compromises.

The fun experience of ham radio is about learning, not buying "mo power."

Rich


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 Post subject: Re: best sw antenna
PostPosted: Jan Sat 25, 2020 7:15 pm 
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Joined: Nov Thu 14, 2019 5:03 am
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Location: n.ca.
receiving only . just using left overs from ham ……….. thanks... steve

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 Post subject: Re: best sw antenna
PostPosted: Jan Sat 25, 2020 7:53 pm 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 10154
Location: Santa Rosa, CA
OK

Adding "mo power" to a receive antenna.... adding a high gain amplifier as most "active" antennas do, can mean just amplifying noise. A good tuned loop will "peak up" what you want to hear, and lose some of the "noise." It is also directional.

http://kr1s.kearman.com/html/hooploop.html

Rich


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 Post subject: Re: best sw antenna
PostPosted: Jan Tue 28, 2020 2:11 pm 
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Joined: Jan Thu 16, 2020 12:29 am
Posts: 177
Best Short Wave Antenna ?

I found out the answer to this question unexpectedly after research on transmitting antennas.

I was comparing loop antennas to whip antennas over the range of 1MHz to 30MHz. This involved a variety of loops and wire antennas, looking at the EM radiation mainly in the near field. Of course, as is mostly the case, a good radiating antenna is also a good receiving one.

So, for the whip antenna I started out with a tune-able antenna from Tarheel in the USA. These were made to be mounted on cars, where the car, to an extent, acts as a ground plane. They have a motor adjustable loading coil to tune them.

So I manufactured another type of ground plane with a large octagonal plate and long radial rods made of 1 cm square section aluminum and fitted the antenna to the corner of my house (see attached photo). The ground plane is also Earthed. (That blimp in the photo just happened to be there and ignore the VHF antenna on the mast)

As a receiving antenna is unbeatable on the SW band and out does all of the other antenna variants I tried. Also as a transmitting antenna, say on 1.4MHz, with a mere 50mW of power the transmission range is astonishing, some hundreds of meters. Though I do not use it for this application, just short wave reception now, but it was an interesting research project.


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 Post subject: Re: best sw antenna
PostPosted: Feb Thu 20, 2020 4:04 am 
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Joined: Jun Mon 04, 2018 3:35 am
Posts: 39
Rich, W3HWJ wrote:
OK

Adding "mo power" to a receive antenna.... adding a high gain amplifier as most "active" antennas do, can mean just amplifying noise. A good tuned loop will "peak up" what you want to hear, and lose some of the "noise." It is also directional.

http://kr1s.kearman.com/html/hooploop.html

Rich

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fm453@ncf.ca


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