ON1BES Labo 2022                      SDR End Fet Antenna

Back to Homepage

Voor NL versie klik hier

New antenna for SDR on the HF Bands (0 - 28MHz)
After years of designing and testing a MiniWhip that couldn't be improved much, I switched to an EndFet antenna. Since I have a small garden, the possibilities are limited, and stretching a dipole antenna was not possible.
But since an EndFet antenna is fed at the end, a short wire of 10 m had to be possible

Possible arrangement: Construction drawing and finishing:
EndFet Schema
Click on the photo for a larger view

Inside the house is a plastic box on the wall with a BNC mounted in it.
From here a coax cable RG58 50 ohm goes out to the duct with the 1:9 Balun.
Cheap TV cable of 75 ohm (RG59) is also good, it is only about a reception antenna.
Not shown, but optional, is a ground wire from the BNC to the outside, on a peg in the ground.
The balun 1:9 is a cheap ready-made PCB (for sale at Ali or Ebay), and is here in a closable plastic tube (made of chewing gum tablets).
From the tube to the wall there is a piece of nylon rope (40cm), (optional) an insulator and back a piece of nylon rope to an eye screw in the wall.
From the tube, 10m of copper wire or more, section 0.75 mm² or more, goes down to an eye screw in a pole about 2 meters high.
Note that the antenna wire ends at the bottom of the insulator in the air at least 0.5m in front of the pole. After all, this is the "hot" end of the antenna.
The 1:9 Balun needs a "counter" weight: an extra wire goes from the balun down the wall. This wire may or may not be grounded to ground, depending on whether the reception results are better or not.
At the end of the cable, down in front of the pole, there is also an insulator and a piece of nylon rope. In my case, to keep the antenna wire taut, the last piece of rope, 1.5m extra, goes through an eye screw at the top of the pole. A weight of approximately 300g hangs from the end of the nylon rope, pulling the antenna wire down, keeping it taut, or "settling" in high winds.
The antenna can be longer than 10m. In my case that was the maximum to stretch, but at the end of the antenna, I tied an extra 10 wire, and stretched it back, diagonally upwards, to where an old TV mast of 6m stands. Now I have a kind of EndFet "V" antenna.
This way I have an antenna of 10m + extra 10m back slanted upwards. Good for the low HF bands.

Photo of the Endfet and the Balun
Blun_2 Balun_2
Balun 1:9 in plastic case Schema Balun 1:9
Full Photo of the Endfet
Foto 3
Photo of the Balun and the Endfet
Click on the photo for a larger view

Receipt results
3 frequencies (EUR) have been tested with this antenna.
1) DCF 77 on 77,500Khz time channel was well received during the day.
2) NDB 355,097 Beacon was well received during the day
3) RWM_Rus_9.995.100 MHz was well received during the day
Certainly not bad with this short EndFet antenna.
This antenna is great for use with my SDR HF UP-convertor : SDR Up-converter v3.0 XT_125
mail on1bes at Scarlet.be