HIREC offers versatile performance in a wide range of fields.
Super repellent material HIREC provides superior functions and performance and comes in diverse product variations. This means it can be used in a wide range of applications.In addition to the examples below, we can help you put it to use in a variety of fields according to your needs.
An example of application to an antenna:
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| Fig.1 : Relationship between rain intensity and rain-attenuation |
Fig.1 shows the relationship between rain intensity and the amount of rain attenuation. Rain attenuation occurs when the transmission frequency is 10GHz or higher. The higher the frequency, the greater the rain attenuation will be. Attenuation is also greater the more it rains. In the 12GHz frequency band, the BS frequency band, rain attenuation is 1dB and 2dB, respectively for rainfall intensities of 5mm/h and 10mm/h.
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| Fig.2 : Relationship between rain and radio waves (example of a broadcast satellite) |
Fig.2 shows the appearance in a pattern chart of radio wave attenuation due to rain on a broadcast satellite (BS) antenna. As explained in Fig.1, rain attenuation occurs when the frequency is 10GHz or higher. This attenuation occurs between a satellite and a BS antenna when it is raining.
Reported cases are rare, but attenuation due to water film is present in addition to rain attenuation. When rain falls on a BS antenna, attenuation occurs due to the formation of a water film on the antenna's surface.
The use of the super-repellent material HIREC is a countermeasure for water film attenuation. When HIREC is applied to the surface of a BS antenna, water film attenuation is dramatically reduced because hardly any water film is able to form on the surface.
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| Fig.3 : Radio reception characteristics of a broadcast satellite antenna (12GHz-band) |
Fig.3 illustrates actual measurements of the reception characteristics of a BS antenna (12GHz-band).
When we ran comparisons with the super-repellent material HIREC present or not present, no attenuation occurred on antennas coated with HIREC in contrast to the approximately 3 to 4dB attenuation with antennas not coated with HIREC during a period of rainfall (17 to 19 hours). Rain intensity is unknown, but no attenuation occurred on the antenna coated with HIREC. Therefore, it is estimated to be 5mm/h from the rain intensity and rain attenuation graph.
As shown in the graph, the attenuation in the 12GHz band during rain of an intensity of 5mm/h was about 1dB. Therefore, the 3 to 4dB attenuation shown in Fig.3 can be attributed to water film attenuation instead of rain attenuation. In addition, the fact that attenuation occurred even 19 hours or more after the rain cleared proves that it is attenuation resulting from a water film still present on the antenna's surface. More specifically, it demonstrates that, when rain falls on the antenna, slight water film attenuation occurs after the rain clears up.
By contrast, no attenuation occurred on antennas coated with super-repellent HIREC. This demonstrates that, virtually no water film occurred on the antenna surface. Based on these observations, the super repellent HIREC can be considered a leading countermeasure for water-film attenuation.
Lastly, you may have heard that water-film attenuation occurs at frequencies below 10GHz, but that is unconfirmed at the present time. We will add the latest information as soon as we know the facts.
A case of snow and ice control measures with a water-repellent sheet for an antenna:
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| A countermeasure with a water repellent sheet makes application possible even in the winter. |
In the past, most of the snow and ice countermeasures were taken by working directly with antennas, and not being able to work on-site as the temperature dropped was a problem in the winter. Here you see an example of a water-repellent sheet that enables snow and ice countermeasures for field equipment even in the winter.
- ♦ Water-repellent sheet advantages:
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- Installation available even in winter weather ← On-site coating on antenna at below 5°C is inadvisable
- Installable in 1 to 2 hours ← Minimum of 2 days necessary for on-site antenna work
- ♦ Water-repellent sheet drawback:
- Lifespan is about 1 year depending on weather resistance of sheet material ← about 3 years for existing on-site coatings
Water repellent sheet structure and actual conditions
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- Reflecting mirror: Apply the super-repellent materials
- HIREC primer coat (pale green section) and HIREC 100 (red section)-to water-repellent polyethylene or polyester sheet (blue section).
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- Photo at right is of a water-repellent sheet on antenna reflecting mirror.
- Converter: Coated by brush only with HIREC 100 (red section).
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- HIREC 100 is a functional material, and causes brush marks (unevenness) when applied with a brush because it is not a coating compound. The white indentations are evidence of good water repellency. (Enlarged view of converter)
Measures against snow and radio reception conditions
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| Feb. 16, 2008 - 8:00 am: Yuzawa, Niigata (approx. 40 cm of snowfall in half a day by 8:00 a.m.) | |
Antenna condition:
- Snow accumulated on arm element, and adhered to part of water-repellent sheet.
- Accumulation of snow to a thickness of 4 to 5 cm on the converter.
Reception conditions:
- Normal reception was confirmed after studying BS broadcasts recorded between 7:00 and 8:00 a.m. on Feb. 16, when snow steadily adhered to the converter.
The fact that reception of BS broadcasts was normal even with snow on the converter is attributed to fact that the converter had been given a water-repellent finish that prevented water from freezing to any significant extent. The super-repellent (HIREC 100) [because it repels water forcefully], is assumed to have repelled the water in the accumulated snow, which did not freeze.
Example of application for bridges or similar structures
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As ice and snow countermeasures, the following two conditions are indispensable to causing deadweight snow to drop off.
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Case of a telecom line snow and ice control measure
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Snow accumulates on telecom wire. |
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Water repellent cover attached to a telecom wire. |
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[captions in photo: Covered wire Wire covers → Cover present] Example of wires with water-repellent covers (foreground). Less snow accumulated than on wires without covers (in back). |
| Water-repellent cover capable of mitigating snow accumulation on telecom wires. | |
Problems such as disconnections on telecom lines or damage to wire fasteners can occur when snow sticks and accumulates on lines in snowy regions.
Snow accumulation countermeasures are also no easier when lines are thin.
Here we show an example of a water-repellent cover that can mitigate snow accumulation on telecom lines.
Features of the telecom line water-repellent cover:
- Snow accumulation breaking points occur because hardly any snow accumulates on the lines with water-repellent covers.
- The telecom line water-repellent cover catches the wind and swings more than when cover is not in place.
Less snow accumulates because of these two functions:
When line water-repellent cover is attached:
- The lower part of the water-repellent cover is built to open up into 2 legs.
- Fasteners are installed on left and right sides of the water-repellent cover.
* Telecom line water-repellent cover material: Polypropylene (PP)
Case of a telecom line snow and ice control measure
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Applications in Electric Power and Energy Field
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Meteorology and Astronomy
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Construction
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Other
- Signs
- Traffic signal hood
- Condensation countermeasures
- Water countermeasures
- Snow countermeasures
- Icicle countermeasures
- Others