Wednesday, 25 September 2013

Antenna options for ISM 433 MHz frequency band - a short guide

The ISM (industrial, scientific, medical) frequency band at 433 MHz is a popular frequency for control, telemetry and access applications. The choice of antenna types is not as great as at 2.4 GHz due to 433 MHz having a longer wavelength than 2.4 GHz, however in most cases there are enough off-the-shelf external antenna options available to address most customer requirements. We'll take a look a some of them here.

In terms of antenna connectors, we are going to assume for the benefit of this overview that the radios are fitted with SMA-Female Jack connectors. In practice, the connector may be different, RP-SMA or BNC or TNC for example.

433 MHz Whip antennas  - often a moulded 1/4 wave whip antenna. It offers more bandwidth than a stub or helical antenna and is often better suited to mobile applications because the inherent flexibility of the whip antenna (they can withstand knocks a bit better than rigid antennas). A typical 433 MHz whip antenna will be approximately 170mm in overall length and will look something like:

433 MHz Whip antenna

The moulded antennas can often have what is known as a skirt - this is the length of moulding that extends past the end of the barrel of the connector (this can be seen in the image above). The 1/4 Wave whip requires a groundplane to operate correctly. Whips can also be permanent mounted with a flying lead for applications where a bulkhead mounted antenna is not desirable.

433 MHz Helical antennas - often a moulded 1/4 wave helical antenna. A typical 1/4 helical antenna is approximately 75mm in overall length. Like a whip antenna, it needs a groundplane to operate effectively, but due to the design the bandwidth of the antenna is smaller than the whip antenna. A typical moulded helical antenna will look something like:

433 MHz Helical antenna

433 MHz Stub antenna - usually shorter than a 433 MHz Helical antenna, the stub is actually also a 1/4 wave helical antenna, but the pitch of the radiating coil is smaller. This affects bandwidth and gain, but when the overall length is 55mm, the small size of the antenna may make the compromised in performance worthwhile. A typical 433 MHz stub antenna would look like this:

433 MHz Stub antenna

433 MHz Wall-Mount - wall-mount antennas come in various flavours, high gain or low cable and with options for integrated cables. As a minimum the wall-mount antenna typically offers 2 dBi gain and is generally designed to feed via a cable to the radio. One example of a wall-mount 433 MHz antenna is shown below:

433 MHz Wall-Mount antenna

433 MHz High Gain Omni antennas -  usually designed for pole-mouned applications, these antennas are typically constructed using a fibreglass tube and can offer 5 dBi or 8 dBi gain. However the compromise for high gain omin antennas is the length of the antenna (they are not discrete), the 5 dBi antenna is approximately 140cm long and the 8 dBi nearly 3M long. These antennas will give you much more range that terminal mount or the wall-mount antennas and some applications require this performance. Below is an example of a high gain omin antenna for 433 MHz:

433 MHz High Gain Omni antenna

433 MHz Yagi antennas - directional antennas offer much higher gain than omni antennas as they radiate broadly in one direction. At 433 MHz frequencies, a Yagi antenna will be similar in size to a traditional TV antenna. 433 MHz Yagi antennas can vary in gain depending on the number of elments the yagi has, but typically the gain can range from 7 or 8 dBi to 14-15 dBi. These antennas are usually pole mounted with a jumper cable to the radio or modem and are designed for outdoor deployment. A typical six element yagi looks like this:

433 MHz Yagi antenna (6 Element)

433 MHz Panel antenna - a panel antenna is also directional in its radiation pattern, more discrete than a yagi antenna, but not offering as much gain, typically gain at 433 MHz could be 6 to 10 dBi. The panel antenna can usually be wall or pole mounted and is fed by a jumper cable. A typical panel antenna looks like this:

The above antennas are the common options for 433 MHz applications - there are of course more specialist antennas such as robust low profile magnetic mounts or collinear vehicle mount antennas - but in many applications a terminal mount, an omni or a directional antenna will fit the bill. The challenge is to understand the trade-offs in performance and select the correct antenna for your application.

For further information, please visit our websites or contact us via e-mail at

Tuesday, 24 September 2013

Maxtena M1621HCT-SMA antenna now available to buy online

The popular Maxtena M1621HCT-SMA antenna is now available to purchase online from the Connex webshop. The product is in stock and ready for dispatch.

M1621HCT-SMA at the Connex webshop

The M1621HCT-SMA is a passive helical style antenna for Iridium applications. A discrete product, the antenna is terminated in a SMA-Male connector. It's small size - just 48mm in height - make idea for mobile terminal applications. The datasheet can be downloaded here via the SAS webpage.

The M1621HCT-SMA antenna is just one antenna from an extensive range of GPS and GNSS antennas from Specialist Antennas including roof-mount, magnetic mount, timing and reference and internally mounted antennas, For more information, please contact us with your requirements.

Sunday, 22 September 2013

New Access Point Enclosure Brochure

A new weatherproof enclosure for access points brochure is now available from PCTEL. Summarising the wide range of PCTEL NEMA-rated enclosures for access points from Cisco, Aruba and Motorola with options for ventilation, PoE, antenna ports and cabling, the brochure is a go to reference point for what is available. The enclosures are typically built and configured to order.

You can download the brochure from the SAS Press Release here.

For further information and to price up an exact configuration, please contact us.

Wednesday, 4 September 2013

Keeping the elements out of your network - NEMA enclosures from PCTEL

Specialist Antennas PCTEL's NEMA rated enclosures are designed to protect a good number of access points from various manufacturers from the elements including wet, corrosive and dusty environments whilst adding security against theft or vandalism. Lightweight and rugged, they are designed to provide maximum durability whilst making handling and installation easier and more straightforward for the installers.

The features of these enclosures include:

• High impact resistance: 1200-1400 in-lb Falling Dart Impact per ASTM 3029
• Ratings: UL/cUL-508A, UL/cUL-50E Type NEMA 3R, 4, 4X, 12, IP66, F1 UV-light, 5VA flammability
• Flat lid surface for easy HMI/pilot device mounting
• Latches and hinges do not penetrate the enclosure
• High performance inserts, molded bosses and integrated hasp lock
• Multi-directional mounting foot kit standard with all models
• Sizes from 6x6 to 18x16 inches
• Seamless gasket for water-tight and dust-tight seal for IP66 integrity
• Customizable mounting panels
• Industrial grey gloss finish

The PCTEL NEMA range accomodates most acces point lines from Cisco in most environments including the following CISCO access points: AP1200, AP1242, AP1250, AP2600, AP3500 and AP3600.

For more information, please contact us on telephone 01280 824055 or via email at

Specialist Antenna Solutions is a specialised distributor of antennas, RF accessories, connectors and cables from market leading suppliers such as Smarteq, Laird, Sirio, MPAntenna, Star-H, Beta Cavi, and more. We offer standard antennas with customised versions available - we can customise cable lengths and connectors in-house. We also offer custom cables based on RG174, RG316, RG58, BW195 and BWL400 terminated with your choice of connectors on rapid turn-around.

Multi-band ceiling antenna for in-building 4G and 3G network deployments

The Connex webshop now has the Laird CMD69273 2 port MIMO ceiling mount antenna available. It is intended to address 3G and 4G inbuilding applications. An aesthetically pleasing antenna, the CMD69273 is designed to be attached to a ceiling grid or ceiling tile. With excellent peak gain figures for a ceiling mount antenna, this is an ideal MIMO antenna for indoors/in-building build outs of 3G and 4G multiband networks.

CMD69273 4G/3G/GSM Ceiling Mount Antenna

Antenna Specification:

Frequency: 690-2700 MHz
698-806 MHz < 2.5: 1.0
806-960 MHz < 2.0: 1.0
1710-2110 MHz < 2.0: 1.0
2110- 2170 MHz < 2.5: 1.0
2300- 2700 MHz < 2.0: 1.0
Nominal Peak Gain
698-960 MHz 3.5 dBi
1710-1990 MHz 5.5 dBi
2100-2700 MHz 4.6 dBi
Average Efficiency
698-960 MHz 90% (max: 96%)
1710-1990 MHz 91% (max: 95%)
2100-2700 MHz 80% (max: 86%)
Polarization Vertical
Pattern Omnidirectional
Input Impedance 50 Ω
Maximum Power 100 W

The CMD is in stock now and is terminated with a 30cm cable and N-Female connector. Go to the product page on the Connex webshop here.