Antenna location : 52.104213, 5,016324 20260512.
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Antenna location : 52.104213, 5,016324
20260512.
| Until 2010 i lived near Rotterdam. After that i
moved to De Meern (Utrecht, NL). I used there the by me designed square
loop antenna of 2,5m x 2,5m for the 80m
and 40m bands. After a very loud BANG from a very nearby lightning strike, my loop antenna showed tuning- and VSWR problems. Parts in the matchbox were posebily damaged due to large RF induction currents in the loop and in the series tuning capacitors. I already had made a spare Matchbox. Several people wanted to help me with replacing the matchbox, but became scared after they discovered that they must stand on a ladder, or had to tilt tthe whole loop horizontally. So i had for more than a year no antenna. "Where is Nico? I do not hear him anymore". I moved. My back hurted and my hart became very weak. In 2025 my spine became so bad, that I could not stand free nor walk free without pain anymore. I needed to much help from my wife. She became overloaded. So I desided mysself, that i had to move to an elderly full care facilty. In june 2025 I therefore moved to such a facility in Vleuten (Utrecht NL). My son-in-law Marc, helped by my grandson Brian, removed the loop antenna from the roof. A new antenna. My appartment is at ground level. But a new Magloop antnna here was to much in plain site. The only possibility was to install a nearly invisible wire antenna. Starting at 3m hight running in direction West to a big oaktree upto 7m hight. From there cornered at 90degr. running in direction South, to another big oaktree down to 5m height.So this is an "End fed" wire antenna. At the start of the antenne is a (2 : 14) turns broadband matching transformer. It is matching the 50 Ohm coax feeder to the 2450 Ohm antenna. The total length of RG316 coax feeder is ca.9m. A commonmodechoke is inserted at 7m coaxlength from the transformer. Ground. I mounted the transformer just outside my livingroom, as high as possible near the ceiling. Screwed to an ALU window frame.That ALU frame is scewed with a havy steel clamp to a steel bushing in the concrete ceiliing. I suppose all these bushings are directly connected to the reïnforcing steel bars of he concrete. In this way all the ALU frames of all appartments above (and maybe aside me) are interconnected with me. Thus forming a big vertical metal frame. A nice "Counterpoise" for an endfed antenna. And I connected the transformer "Ground" connection to the ALU frame. VSWR. i measured the antenna resonance frequencies. At the frequencies of best VSWR (the antenna resonance frequencies) the "VSWR < 1.5" bandwidths were VERY WIDE. A big surprise ! When the antenna is trimmed for correct resonance frequencies, whole amateurbands above 7MHz could possebly show VSWR < 1.5 A true wideband antenna HI. .Maybe a tuner is not needed! At the mment resonaces are still about 4% to low for bands from 40m to 10m. On the 80m band the resonance frequency was even 12% to low. Antenna trimming is therefore needed. Trimming. First trim the long antenna wire for correct resonances on all 7Mhz, 14MHz, 21MHz and 28MHz bands. When one band resonates on the mid of the band, all these bands should show good VSWR over the entire band range. Trim short peces and check resonaces. Other bands inbetween need a tuner and possebly lower RF power. Secondly trim the short antenna wire carefully for 80m midband resonance. The "VSWR<1.5 bandwidth" will however be very narrow (60 kHz ?).
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