In december 2015 I completed a new antenna for shortwave in the garden!
The construction is an EWE-antenna, based on Koontz concept from 1995.
Since the EWE is known for low signal output, I have constructed the balun (transformer) with 25 turns of trifilar 0,6mm (#23) enameled copper wire on a FT140-43 toroid. The FT140-43 was not the toroid suggested in most articles, but I found a few that had it in their construction! And the usual suggested turns was 9-11 trifilar, certainly not 25! Did I do wrong, would the impedance fail?! In the real world I just can conclude that my EWE-antenna does not need a preamplifier to let me hear stations out there. And the signals are low noise compared to my other antenna systems. Especially on the lower bands, but it can be noticeable even up to 15MHz.
(See also a presentation of the EWE-antenna hold 2017-10-03: Experience of an EWE-antenna presentation 20171003 engl ver ).
Here is the layout for the termination net. The reed relays are closed by neodym magnets placed outside the plastic holder. When the first relay was just inside the opening of the plastic holder, I bent it out to the surface of the holder. Then I made the same procedure with the next relay as it reach inside the opening. By making the relays come close to the surface of the holder, I can use magnets outside the holder to close them. Carbon resistors have the best RF-properties.
As antenna line I have used a 3,5 mm insulated copper wire, with 7 strands of 0,57 mm (23# AWG), forming 1,78 mm2 (3,6 kcmil).
After the installation of the EWE-antenna my AR7030 have been spinning around the world! And in march 2016 I have logged transmission sites in 59 countries. Although they are not confirmed with QSL-cards, the verification has only been done via ‘short-wave.info’ and ‘mwlist.org’, I think this is a great success as a start in my DX-career! The verification is done by recording the display and sound on the receiver with a videocamera and at the same time also the information on the appropriate site. The sound ID from the videocamera has then been extracted and is listed beneath. All those heavy videorecordings are then stored in an archive.
After living in our house for 30 years, now (spring 2020, during the peak of the Covid 19 pandemi!!) its time to move to a flat close to the centre of Härnösand. This means the end of the EWE-era for me. The antenna has been dismantled from the garden and is now in care by another DX-er here in Härnösand.
To be able to DX from our flat I will try to build a loop-antenna, based on Chris Trask’s design “A High Dynamic Range Amplifier for Wideband Active Loop Antennas”, see side 28.
The printed curcuit board has already been etched and the components bought from Mouser!
63. Tajikistan sound ID, Radio Free Asia, Dushanbe-Yangiyul, 13830khz, 20170420
64. Slovenia sound ID, Radio Murski Val, Murska Sobota_Nemčavci, 648kHz, 20171110
65. Slovakia sound ID, R.Patria Maďarsk_R.Devín, Nitra_Jarok, 1098 kHz, 20180107,
66. Russia sound ID, Radiogazeta Slovo_Pravoslavnoye Radio Sankt-Peterburg, Sankt-Peterburg_Sosnovka, 828kHz, 20180906
67. Egypt sound ID, ERTU Al-Quran al-Karim, Santah, 864 kHz, 20181011
68. Syria sound ID, SRTV 1 Dimashk SRTV Radio Damascus, TartusBesira, 783 kHz, 20181014
69. Cyprus sound ID, Radio Sawa, Cape Greco, 990 kHz, 20181105
70. Israel sound ID, KAN Bet, Tel Aviv_Yavne, 657 kHz, 20181109
71. Saudi Arabia sound ID, Republic of Yemen Radio, Jeddah, 11860 kHz, 20181128
72. Djibouti sound ID, Radio Sawa, Doraleh, 1431kHz, 20190219