Yagi

82 83TELE-audiovision International — The World‘s Largest Digital TV Trade Magazine — 03-04/2014 — www.TELE-audiovision.com www.TELE-audiovision.com — 03-04/2014 — TELE-audiovision International — 全球发行量最大的数字电视杂志

Yagi U-PA UHF Antenna

• very good performance• very wide beam • ideal to use with local reception• compares favorable to a much bigger

outdoor antenna• home-friendly design

TEST REPORT Terrestrial Antenna

03-04/2014

www.TELE-audiovision.com/14/03/yagi

84 TELE-audiovision International — The World‘s Largest Digital TV Trade Magazine — 03-04/2014 — www.TELE-audiovision.com

TEST REPORT Terrestrial Antenna

Terrestrial TV does not offer as wide a channel choice as satellite TV, but it has other strong points, namely in most countries among the terrestrial chan-nels you can find the local tv channels providing informa-tion on what is going on in your neighborhood. Another strong point is that setting up a terrestrial antenna can be a simple and easy-to-do task.

“Can be” does not mean “always is”. If you want to install a multi-element yagi antenna with complex reflec-tors your antenna setup will become a rather complex one. That’s why many people prefer simpler solutions and small compact TV antennas are becoming more popu-lar. Generally, they cannot offer as good performance as a full size multi-element yagis but if you live not very far from the TV transmitters they can ensure a quite solid reception while being very simple in installation. And, if nicely designed, they can be more esthetic than yagis.

The Yagi U-PA fits all of the above. Its size is quite small: 35 x 13.5 x 12.5 cm and it is very light – ca. 0.6 kg. It can be used either indoors or outdoors. In the latter case you simply attach it to a pole with two butterfly nuts, which are part of the pack-age. You do not need to use any further tools.

Its double panel radiators are completely hidden in a plastic enclosure so in fact the antenna does not look even like an antenna. That is especially nice when you opt to use it indoors rather than outdoors. The antenna is available in white or black color.

And what about the tech-nical specifications of the Yagi U-PA? The manufac-turer promises a reasonably wide frequency range of 470 ~ 770 MHz (UHF channel 13 through 69) and a good gain: 4 ~ 5 dB. Its Half Power Beam Width (HPBW) is very large: 76°. This means that when it receives a signal lo-cated +/-38° off its center line the antenna output will

Yagi U-PA UHF AntennaExcellent

technical performance

Small But Surprisingly Efficient

be attenuated only by 3 dB compared to the signal com-ing directly from the front. Thanks to this uncommon feature this antenna in many cases will be suitable to re-ceive not just one but two or more TV transmitters that are located in a similar di-rection from your home. And this means, of course, more channels to watch, without moving the antenna to an-other direction.

The Yagi U-PA is not sym-metrical – it has a front and a back. If you turn it around

(180°) it will attenuate the signal by 9-12 dB. In this as-pect it is similar to a multi element yagis.

Speaking of multi element yagis: we decided to use one as our reference antenna for comparison. Of course this big yagi had much more su-perior parameter specifica-tions. Its gain was 9 ~16.5 dB and thus 4 ~ 12.5 dB bet-ter than the Yagi U-PA. We decided to measure both antennas to check if the dif-ference was not greater than our theoretical calculations.

www.TELE-audiovision.com/13/09/spaun

■Fig. 1 Reference antenna spectrum

■Fig. 2 Yagi U-PA antenna spectrum

Transmitter Frequency [MHz] 561 634 666U-PA Antenna Output Power [dBμV] 57 55.2 50.4

Multi-element Yagi Output Power [dBμV] 60.5 59.8 56.9

Transmitter Frequency [MHz] 561 634 666U-PA Antenna MER [dB] 31.8 31.9 25.4

Multi-element Yagi MER [dB] 33.2 32.7 31

■Table 1: Antenna Measurements - Gain

■Table 2: Antenna Measurements - Quality


As can be seen in Table 1, the difference in antenna gain was from 3.5 to 6.5 dB. This means much less than what we expect-ed from the specifications. This point clearly goes to the Yagi U-PA!

Then we observed the full spectrum at the output of the Yagi U-PA and the output of our reference multi element yagi. As you can see in the pictures, the difference is indeed surprisingly small.

Please note: at the left hand side of the picture you can see the VHF radio band. None of these antennas is suitable for the reception of this band – so the difference between them does not matter. What counts are the three peaks in the right hand side of the spectrum which are 561, 634 and 666 MHz, rep-resenting the terrestrial UHF transmitters available at our test location. It is clearly visible in the screen shots that the dif-ference between the antennas is just a few decibels, matching the results of the channel power measurements we did before.

Naturally, if the signal at the antenna output is weaker, than its separation from noise de-creases. We measured MER for both antennas to evaluate qual-ity of the output signals.

MER was almost equally good for the YAGI U-PA as for our much bigger reference antenna for 561 and 634 MHz. Only for the third lower power transmit-ter at 666 MHz we noticed a de-terioration of the signal quality. However, it still had almost 4 dB (3.9 dB) noise margin. So, even in worse weather conditions you should not be afraid of loosing the service.

To sum it up, the Yagi U-PA performed very well for its class. If you receive a signal from typical local TV transmit-ter you can expect solid recep-tion within a distance of 30 km or so around the transmitter site. If you put the antenna in-doors the practical range will decrease to 20 ~ 25 km.

OPINIONExPERT

+

–

RECOMMENDEDPRODUCT BY

Jacek PawlowskiTest Center

Poland

Yagi U-PAUHF Terrestrial Antenna


● Small compact size and weight● Unobtrusive design● Large HPBW allowing reception of a few transmitters at dif-

ferent azimuths● Surprisingly good signal gain despite its small dimensions

● Its frequency range does not cover the full UHF range and is limited to 770 MHz

Documents

Yagi