Due to the accessibility of the balcony at the place of my stay, I decided to install the Ground Plane antenna on all amateur ranges of 7-28 MHz, and, if possible to configure, then at 3.6 MHz. The basis was taken from the article http://www.dk3red.homepage.t-online.de/de/s15_01.htm. The antenna is a fishing rod with a tuner at the base, grounding on the railing or a balcony glazing frame.

1. The first version of the antenna is a 4.5m wire and a hand tuner

In the first version, I placed a radio station and a hand tuner on the balcony. This is an experimental option not for working on the air, but for "evidence of the concept" and checking the possibility of working from the balcony.

As a mast, I used a carbon fiber (carbon fiber) rod 7 meters long. Throughout its length, with the exception of the handle, which is located in the room, the wire with a large step of the turns is wound.

1. Antenna canvas - wire 4.5 meters long.
2. The same as 1 with an extension coil to ensure resonance at a frequency of 7 MHz.
3. Antenna canvas - wire 6.8 meters long.

All antenna options were measured by the Nanovna antenna analyzer without using a tuner.

1А. The first version of the antenna is a wire of 4.5 meters and an automatic tuner

The antenna without a tuner has an active resistance of 11 ... 53 Ohms (reactivity does not exceed 100 in the range of 28.14 and 10 MHz).
In all ranges, except for 3.5 MHz, the input resistance is convenient for coordination by an automatic tuner.

График Short wire

The resonance of the antenna with a wire length of 4.5 meters lies at 12.5 MHz (between the amateur radio ranges of 10 and 14 MHz).

It should be noted that the increase in the input resistance R Antenna at low frequencies 3.6 MHz is apparently due to the fact that:

• The tuner in the first version is connected to the ground using a wire 2 meters long - it turns out like a GP with a displaced power point, which increases RVX.

1Б. The first version of the antenna is a wire 4.5 meters + lengthening coil for the range of 7 MHz (without tuner)

График With a coil

A KSV in one low -frequency range of 7 MHz improved (SWR = 1.8), while in the rest the coordination of the antenna with the cable has sharply worsened.

Impressions from the first version of the antenna (1, 1a, 1b) with a length of the wire 4.5 m, grounding a wire 2 meters

In high-frequency ranges of 14-29 MHz, the antenna is little susceptible to interference (quiet), especially if you connect it to a manual tuner, and when the transceiver is powered by the battery. The antenna also works well in the ranges of 10-29 MHz.

2. The second version of the antenna is a radiator of 6.8 meters, the grounding wire of the minimum length (0.3m)

Для работы в диапазоне 7 МГц нормальная длина излучателя 10 метров - что составляет 1/4. Тем не менее. более короткий провод 6.8 метров тоже работоспособен: длина излучателя равняется 0.16 длины волны в диапазоне 40 метров и 0.08 длины волны в диапазоне 80 метров. Лучше всего такая антенна работает в WARC диапазонах 30 метров (10 МГц) и 17 метров (18 МГц).

Graph of a long wire 6.8 meters

In this version of the antenna, with a wire of 6.8 meters, the coordination with the cable in the range of 40 meters worsened compared to the first option (with a long grounding conductor). In the 3.5 MHz range, the antenna is built by a tuner (the active part 53 Ohms plus the capacitive component). In the range of 14 MHz high input resistance 1 kOhm.

Impressions from the second version of the antenna - wire 6.8 meters and a short grounding conductor 0.3 m

1. This version of the antenna is interesting in that the reception in the range of 14 MHz is much superior to the transmission.
2. The antenna of 14 MHz does not need counterweight - high input resistance of 1000 Ohms (voltage resonance). Nevertheless, the antenna is built by a tuner - several radio communications were carried out on the antenna with a wire length of 6.8 meters in the range of 14 MHz.
3. Despite the decent height, the antenna is very inferior to the directed (I hear who the other radio amateurs of St. Petersburg hear) - in the range of 14 MHz, 6 and 9 areas (Krasnodar, Urals) are good, but there are not even a presence, there are not even signs of stations from Siberia. On FT-8, only traces of stations from China are visible. Perhaps this is due to the shielding of the house from the northeastern direction. At the same time, Europe passes with high levels, at 2000-3000 km distances, everything is wonderful.
4. When placing the wire of the antenna canvas, although it is in isolation, it should not touch the railing of the balcony, because The Earth's container increases. Also, the lengthening coil at the base and the spiral antenna on the fishing rod should be far from the metal fence. Otherwise, the lengthening coil does not behave as a pure inductance L, but as Mr. From L and C, with unpredictable resonances and a decrease in efficiency.

The third version of the antenna - the wire 6.8m with an automatic tuner on the balcony

The purpose of the third option is to transfer the transceiver to the radio room (Shek) to work from more comfortable conditions. Of course, a decision was suggested with a remote automatic co-consonant of the CG-3000 manufactured by Belgium (for a capacity of up to 100 W), which was purchased earlier. The automatic tuner is tuned remotely at any frequency at the signal from the transceiver. It has no control cables, except for the 12 volts from power supply from the power circuit for the electrical circuit of the relay. The tuner is tuned to the frequency of the input high -frequency signal.

Impressions of the third option - with a volume tuner

1. Compared to the manual tuner, the reports I received (my signal ratings) have somewhat deteriorated (from 1 to 10 dB). This is most likely associated with inaccurate coordination to KSV = 1.5, while the manual tuner made it possible to achieve KSV = 1.0. But for the FT-8 mode, this is not significant, a fee for convenience (setting speed, multi-dimensionality).
2. In the range of 14 MHz, the noise of the ether increased to the S7 with an automatic tuner on the balcony compared to the S1-S3 when using a manual tuner. The reason for the poor technique is symphasial obstacles.
3. Wounding of domestic interference from an alternating current network to the tuner power cable was found. In the range of 80 meters (3.5-3.8 MHz), the most loud stations were heard against the background of the characteristic “growl” of interference from the electric network - a consequence of the symphazic interference and the current loop on the braid of the coaxial cable - the transceiver - tuner - control cable.

The fourth version of the antenna (final) - the option No. 3 with a volume tuner is taken as the basis. Added shut -off throttle on all cables and a symphasial filter for power 220 volts

Since the source of interference was installed accurately - symphasial obstacles, it took a bloom at a high frequency from the network of 220 volts and from the room (in which all wires are interfered):

1. To prevent symphasial interference on the outer braid of the coaxial cable, a large Balun is installed in front of an automatic tuner in the form of winding 8 turns on a plastic cylinder with a diameter of 10cm - the so -called "Ugly Balun".
2. To minimize interference along the tuner power cable, the wire near the coordinating device is passed through 7 ferrite rings - each in each of 3 turns. The “garland” from the filters was removed with the tuner in a plastic suitcase (bought for 500 rubles).
3. From the 220 volt power supply, the transceiver power supply is connected through the EMI Filter filter with AliExpress to a voltage of 220 volts and current 30 amperes. The interference filter is installed in a plastic mounting box purchased in a construction store. A socket is installed on top of the case, the filter has a wire with a fork for connecting to an electric network 220 volts.
4. To reduce the internal interference from the building on the antenna canvas, the loop of the wire from the fishing rod to the coordinating device was removed. For this, the tuner is raised up and tied to the railing of the balcony. The grounding wire to the railing of the balcony is shortened to a minimum.

The use of these measures made it possible to reduce interference from 8 to 4 points in the range of 80 meters (by S-meter with the IPO button on the preliminary amplifier), that is, the interference level was reduced by 24 dB! As a result, I hear 80 meters better than they hear me. I accept all local stations 80 meters from St. Petersburg and the Leningrad Region. The leading round table for 3630 kHz is 9+ points. They also answer me (of course, not 9 points, but "up to 9").

The connection diagram of the antenna is given below :

The appearance of the filter of interference from the network 220 volts

Click to increase:

The power filter is installed in the radio room. The transceiver power supply is connected through this filter.

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