Basketenna!

Look also https://sites.google.com/site/zliangas/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 temporary 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 :

radio alone	PL360 : 24 /10	DE17 : 53	PL380  25
besketena	37/24	53	52
1 x 1 loop	55/24	64	63

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

Freq	AN200	basketena
531	15	25
576	25	40
864	35	45
1008	35	44
1404	40	49

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

ADDITION 30/6/23

After very long time and leaving that in a corner in the house i once again used it to test and comparing with the AN200 . Previously i used part of its wire for other uses and possibly reused it after keeping it I m not very sure 

 

using a viontage PL250 radio and the vintage antenna This radio is one of the oldst tescun radios we had as itis in the vintage box used only as alarm for my wife and then was put in the box it is just a monophonic radio  it can be shown There is a jumper missing but still has some goos amplification in all the MW band Fond another alligator jumper from the nomad;s bag and used it but..

...this jumper was shortcut as tested with the multi-meter ! Finally after buying a new battery (more than 5 years to use it )and buying  a new set  of cables the problem solved. Previously reception was too wide with the cap with a bandwidth of 400+kHz

Experimenting once again with this antenna . 

The wire windings are only 20 and tested well with the capacitor to give quite narrow bandwidth but ....

....  the 3 position capacitor  works as like it is connected in between with the same top in each end!

.....the total tune with the 20 winds are 430-1140 kHZ . Used the PL330 for cheeking that. IN contrast with the 22 winds the antenna cold rage between 1700 to 530 kHz..

....with the remain add-on cable with bandwidth down to 360-kHz good for checking a few local NDBs , There was a funny problem . the highest tuning frequency is higher than with the 20 wounds!

Experimenting by stripping parts of the cables  i found the same problem . The antenna shown some highest that are lower than of the 20 turns!!! As for example the 15 turns point shown highest tune no 1170!!

I really wonder on how it can happen this antenna is now voiding any theory!