In a radio component store, I bought a room antenna for 200 rubles ($ 3) in order to check what it is capable of taking radio waves of the VHF range.

The television antenna ZOLAN FB-618 was made in China, designed to install indoors: on a table or other flat surface (on a shelf, windowsill). It consists of two parts-a dipole of meter waves 49-230 MHz with a variable angle between the shoulders of the dipole and a circular vibrator (two combined frames) for taking decimeter waves of 470-900 MHz. The antenna is connected to the television receiver with a 75 ohm cable 1 meter with a standard TV F-type connector.

Antenna check on a vector analyzer

Using an antenna analyzer nanoVNA I checked the antenna's operation Zolan FB-618 in various ranges of radio and 2-meters amateurs' band.

Aviation band 108-135 MHz - The telescopic shoulders of the dipole are laid out to the sides.
The antenna shows a good matching with the cable in this range. Active and reactive resistance almost does not change, the SWR (Standing wave ratio) in the range from 118.7 to 130 MHz is no worse than 3. The input resistance is low 20-40 Ohms with the capacitive component of reactivity, which, depending on the frequency, gives 1,5-3 SWR.

Two-meter band, 140-170 MHz - it is necessary to reduce the length of the shoulders of the dipole, folding it to 2 knees on each side and place it with V-shaped.
The antenna is not agreed with the cable: even when choosing the length of the shoulders according to the analyzer, the SWR remains higher than 3.

The UHF television band or "decimeter waves" in the range of 470-790 MHz, for DVB-T2
(The elements of the dipole are folded and set vertically).
The antenna in the UHF band is perfectly matched with the cable (input resistance from 40 to 100 Ohms and has 9 resonans (I express respect to the developers!). SWR in the entire range of 470-790 MHz is not more than 2. The input resistance of the antenna 50-100 Ohms provides good consent with a 75 Ohms cable.

Practical test antenna

Antenna was connected to the receiver for the air band (transciever Yaesu VX-6r is used) through an F-SMA adapter and showed high signal levels near Pulkovo Airport: S9 pilots, S3 controller. Compared to the standard dual-band 144/433 MHz antenna, when using Zolan FB-618 anetnna there was no disappearance of voice and potato-potato-potato-potato (Squelch).

Advantages and disadvantages

Advantages: Antenna Zolan FB-618 has a low price, but at the same time it is made qualitatively: the dipole shoulders are securely fixed in the right position, the nested frames are connected by welding and the chrome coating is applied, the plastic base looks neat. You can choose the options for the diploma configuration: both shoulders are horizontally or one of the shoulders vertically (for taking horizontal or vertical polarization).

The main application of the antenna is for DVB-T2 digital television in a decimeter range of 470-790 MHz. In this range, Zolan FB-618 is well matched with a 75 Ohm cable.

Disadvantages : High SWR in a two -meter band of radio waves (VHF), except for the aviation range. The spot of the best SWR is above the broadcasting FM band, which does not allow the use of this antenna for the receiving of the FM radio stations. It is impossible to configure the antenna for receiving a radio amateur range of 144 MHz.

Conclusion

Antenna Zolan FB-618 is good purchase for receiving digital television DVB-T2. Radio amateurs and can use this indoor antenna to receive an aviation band.

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