MW basket antenna!!

This antenna was an inspiration from a ham radio operator and friend who made a nearly same design using a vegetable basket from bazaars . Although I have two MW antennas this idea made made me very curious for testing such an antenna

This is a useless basket taken from a mini market . Trying to unwind the wire was very hard as it was hardly bended and I lost about `1.5 hour to straighten it … And still there was a small problem as about 6-7 cm were bended insie

Calculations have been made with the jelp online loop calculator at this address after a discussion on loopantennas goup

http://www.angelfire.com/mb/amandx/loop.html

Using the exact dimensions of 30 x 50 x 26 height the result was 22 winds with 0.5 inch step of winding and start from 1620 kHz to ca 530

Coiling the basket was then quite easy though several winds were terminated on the ‘bones’ of the basket and soe oter windings were a little loose . Stepping in practice was quite lower just 4- 10 mm due to basket height restraints . I kept 23 windings and a multi stranded wire of 0.5 mm2 thickness (specialized for cars ) that was on my 'garage'

The blackbox of the mag loop has been used as tuning capacitor a very good design with 2 step multi turn and total capacitance of nearly 650 pF . The switch is here off using only the 450 pf.

Here is the inner side of the black box The real capacitances are 11-188 pf and 125-452 pf

Wires are directly connected to the inner part of SO239 connectors The technician suggested the wires to connect to the black sockets ('bananas')

And finally the antenna worked ! I was expecting it to work to max 1700+ but the highest freq was 1620kHz . POssibly one less winding could resolve it but i didnt test so far

This 2 step capacitor tuned :

With main cap with the range of 720- 1620kHz

Using the 2 step cap : ca 480-837kHz

MY tests in the night revealed induction signals to vanish to 45 cm of distance !! You can compare with the distance of An 200 which is ca 15 cm Thus the most modest distance with still good results on nights are this (about 15 cm from the basket frame ): My next experiment is to compare this induction distance with the Australian loop (the 1x1 m antenna shown here )

Another way to have very great signals is to put your radio inside the basket : this idea can offer the highest signals even if the radio was put on the top of the basket

New testing with antenna touching the marbled wall hugely increased the signal and touching the radio near to the edge of the basket receives the highest possible signal . Using the DE 17 radio and tested with the signal indication , a signal rated as 15 can have a signal of 26 atop the antenna and 45 in the edge! However I am not 100% sure if these indications correspond to db units

New test using a 3 x500 pf ,that possibly willb e permanent

As the capacitor is for use with the mag loop , i used another cap of 3x500 pf of my shack . As the test in the srtart will be just temporaary i used alligator clips for the joints:

Here is a close up with the connections :

and here is how i 'fixed' the capacitors on the basket ! the fixing was still veryloose and i used a useless pencil to keep some of the air!

the results are exactly the same though in the start due to possibly compact winding on windings , the highest frequency dropped to several kz and it was the start freq for the capacitor!!

New experiments : comparing basktena with Australian loop and AN200

Yesterday 3-7 i was experimenting with m 1x 1 sqm loop and the AN200 antenna

The forst test was between 1x1 m loop and the basketena .

as oyu watch in the above photo , both antennas have at least 3 m distance so that none cold effect the other antena .

I put the 'black box' as tuning capacitor fort the 1 x 1 m loop and the basketena used the 3 x 500 pf capacitor . There was a problem with the black box as it tuned only in the higher freqs of the spectrum with high Q

Mathematically the 1 x 1 m antenna has 6 times the area of the basket.

These are the results for 1404kHz which was the only freq tested with it with three DSP radios :

Under this i suppose that 17 and 380 have the same readings and the field is 9 db higher than the basket's .

Her is a closeup of the 1 x 1 m loop antenna

and here are the results between An 200 and basketena with nly De17 . I can suppose that the readings on the radio could be in db , though as noticed in a web page the db readings are of the current received in a pin of the IC

MY opinion is that basket in the middle between Australian and AN200 in terms of efficiency .

Update :

ON the end of September the loop has by itself increased inductance, lowering the top frequency by 30-40 kHz , ie from ca 1650 to 1620 . I unwounded the loop by 1 wound .This happened 2 times again and I responded the same way . Now end of October the loop consists of 20 wounds and tunes to 460 - 1750 kHz (measured with PL380)

And some experiments :

Some hard to listen stations as revealed with this antenna on times 2030 -2100

792 Arabic station

927 Arabic

1044 Spanish , poor

1323 a Greek pirate

1395 Russian – golos rosii poor

1413 Spanish RN 5 poor

1476 Arabic poor