Sunday, June 24, 2012
Tyco enhances SFP product line/Mindspeed debuts 11.3G chipsets
APRIL 28, 2009 -- Tyco Electronics (search Lightwave for Tyco Electronics) offers a complete small-form-factor pluggable (SFP) product line, including single-port and higher density multiport SFP cages in single row and stacked configurations. Tyco Electronics has introduced new options, including integrated lightpipes for port indicators, connectors with improved signal integrity, enhanced EMI springs for increased EMI suppression, and riding heatsink technology for thermal management.
The pluggable I/O interface includes a standard equipment I/O interface; with the flexibility of pluggable modules and cabling come options of fiber and copper links. It also supports various data rates and protocols including Ethernet, Fibre Channel, and InfiniBand standards. As a result, the integrator can design the cabling structure based on the application needs.
To address market needs for greater density in high-speed pluggable devices, the quad small-form-factor pluggable (QSFP) interface was developed, providing a four-channel, 40-Gbps pluggable interface. As data rates reached 10 Gbps, Tyco Electronics played a role in developing the 10-Gigabit Serial (XFP) standard and the X2 MSA, the XAUI-based 10-Gigabit standards solution. Key proven technologies from XFP were adopted in this design.
Direct-attach cable assemblies are engineered with these pluggable interfaces. Copper cables are cost effective for short-reach applications and are available with passive and active equalization. Active optical PARALIGHT cables are available for QSFP, which eliminate the need for a transceiver/cable interface.
Components of a pluggable I/O interface include:
a host board connector
a cage or guide rail, which provides EMI containment and guidance for the mating plug
a mating plug, which may be in the form of a pluggable transceiver or direct-attach cable assembly. A transceiver requires a mating cable assembly
accessories include heatsinks, lightpipes, dust plugs, and EMI plugs
APRIL 29, 2009 -- Mindspeed Technologies Inc. (serach Lightwave for Mindspeed) has unveiled chipsets for 10-Gbps serial optical links.
Building on the company's expertise in GEPON and GPON and cultivated by three generations of 10 Gigabit products, Mindspeed's newest offering is designed to provide a complete serial link approach for applications to 11.3 Gbps.
Said Hasnain Bajwa, Mindspeed's senior vice president and general manager, lightspeed connectivity solutions, "Our new chipset includes the world's first dual-rate 1-Gbp and 10-Gbps transimpedance amplifiers, post amplifiers with internal digital controls, and laser drivers with optical modulation amplitude control."
Mindspeed's new 11.3-Gbps product offering includes a high sensitivity multi-rate limiting transimpedance amplifier (TIA), a linear TIA with low total harmonic distortion (THD), linear and limiting post-amplifiers with digital controls, directly modulated laser (DML) and vertical-cavity surface-emitting laser (VCSEL) drivers with optical modulation amplitude (OMA) control, and an electro-absorption (EA) modulator driver.
The M02129 TIA supports dual data rates of 1.25 Gbps and 10.3 Gbps, which Mindspeed asserts makes it the industy's first rate-selectable TIA for 1-Gbps/10-Gbps Ethernet. Featuring -21-dBm OMA sensitivity at 1.25 Gbps and -17.5-dbm OMA sensitivity at 10.3 Gbps, the M02129 is suitable for systems requiring backward compatibility.
The M02130 linear TIA is intended for use in equalized systems where low-distortion is required. Featuring less than 4% THD over the range of -17 to +1 dbm OMA, the M02130 passes the stress tests imposed by the 802.3 10GBase-LRM standard.
The 11.3-Gbps post amplifier (M02142) and linear amplifier (M02143) are among the industry's first post amplifiers to have internal digital controls, Mindspeed says. The M02142 features 5-mV input sensitivity with loss-of-signal (LOS) circuitry capable of supporting out-of-band (OOB) signaling. Programmable LOS and output de-emphasis can be accessed via the 2-wire interface, while an analog-only mode may be used in more traditional applications that only require the chip's small size, low power, and sensitivity.
The M02143 is a differential gain amplifier for linear systems with 3.3-mV sensitivity at 11.3 Gbps and a maximum 4% THD. The post amplifiers are available in an industry-standard 3x3-mm quad flat no-lead (QFN) package.
The M02170 DML driver provides up to 85 mA of modulation current and 150 mA of bias current, while the M02171 VCSEL driver provides up to 15 mA of modulation and 15 mA of bias current for VCSEL applications. The M02172 EA modulator driver delivers up to 2.5 Vp-p into a 50-ohm modulator with 0-1 V offset control and up to 150 mA of bias current. All drivers include circuitry to facilitate extensive monitoring and control and are available in an industry-standard 5x5-mm QFN package.
When combined with the M02129 TIA and M02142 post amplifier, the M02170 laser driver and M02171 VCSEL driver provide a total approach capable of supporting the <1-W transceiver power demanded for SFP+ applications, the vendor concludes.
Monday, June 18, 2012
Malarenergi goes gigabit-to-the-home with PacketFront ASR6000/Infinera asks, what's your network efficiency quotient?
Mälarenergi, a Swedish open access network operator with over 31,700 connected homes, has placed an order for approximately 1200 units of PacketFront’s ASR6000 system. The ASR6000 is a Layer 3 Gigabit Ethernet access switch (see “PacketFront intros ASR6000 gigabit-to-the-home platform”).
The ASR6000 units will be deployed over the next 18 months and will upgrade 28,000 ports of the access network in the City of Västerås to support gigabit speed services.
“We are proud of our ability to maintain and operate a large distributed open-access network with a minimum of resources,” said Per Norrthon, CEO of Mälarenergi. “PacketFront’s ASR6000 is a key factor to continue this lean operation as we move to gigabit access. The citizens of Västerås will now enjoy an even wider selection of services and we have a very easy migration process to update the network with the new routers.”
The ASR6000 supports multi-rate operation for both copper and fiber ports, which means that the end-user equipment does not have to be replaced until faster services are purchased. The small form factor of the ASR6000 also allows it to fit into existing installation sites, enabling a “plug’n’play” migration process for Mälarenergi to minimize network down-time when old hardware is replaced, PacketFront says.
“The ASR6000 was designed to make the migration to IPv6 and GTTH [gigabit to the home] as simple as possible, something that Mälarenergi and other customers have stated as a key criteria. We have listened and Mälarenergi’s continued confidence in PacketFront is proof of that fact,” said Johnny Hedlund, CEO of PacketFront Network Products AB.
To promote the benefits of integrated OTN switching and WDM – attributes of its DTN-X platform – Infinera (NASDAQ: INFN) has introduced the concept of a network efficiency quotient (EQ), plus a handy way to measure it.
As the term implies, EQ is a way to describe the efficiency of a network’s architecture and relate that efficiency to total cost of ownership (TCO). Infinera now offers a pair of tools on its website that measure and predict network EQ. The EQ Estimator is a 10-question survey that participants can take anonymously to determine their network EQ as Infinera defines it. The EQ Power Analyzer measures power efficiency across four 100-Gbps network scenarios. If you want more details on how to improve your network’s efficiency, you can discuss it with an Infinera representative via EQ Engagement.
As Infinera Senior Director, Corporate Communications Mark Showalter described it, a network with a high EQ features limited stranded bandwidth enabled via high-speed, high-capacity multifunction transport platforms. Infinera sees OTN switching as the best way to minimize stranded bandwidth; integrating this capability within the transport platform, rather than using a standalone system, saves space, power, and operational expense, the company says.
At least one Infinera customer buys the premise. “Through several years of deploying and maintaining Infinera technology across our optical transport network we have enjoyed the improved network efficiencies enabled by a system that combines OTN switching with Photonic Integrated Circuit-based WDM optics,” said Randy Nicklas, senior vice president and chief technology officer at XO Communications. “By working with Infinera, we’ve been able to realize the benefit of increasing wavelength efficiency while reducing space and power consumption compared to alternative solutions.”
“Our recent “OTN Deployment Strategies: Global Service Provider Survey” showed that 75% of operators plan to deploy OTN switching in their networks and more than half of these desire OTN switching integrated with WDM,” added Andrew Schmitt, principal analyst, optical at Infonetics Research via an Infinera press release. “Operators plan to deploy OTN switching in combination with WDM in order to improve network efficiency and lower network lifecycle costs. I’m pleased to see that Infinera has developed a framework that will help operators evaluate their architectural choices.”
Monday, June 11, 2012
PacketLight Networks enhances video support/IFN taps Ciena for packet-optical upgrade
PacketLight says it has enhanced support for video interfaces in both of its Optical Transport Network (OTN) and transponder-based offerings. The new feature is designed to enable efficient and simple streaming of high-capacity video for broadcast media companies and digital studios over fiber and standards-based OTN networks.
Different copper interfaces for video such as SD-SDI, HD-SDI, 3G-SDI and DVB-ASI are all supported by PacketLight's CWDM/DWDM and OTN product family. Additionally, video signals can be mixed with other data and storage traffic such as 1G/10G Ethernet and 1/2/4/8/10G Fibre Channel.
Use of the PacketLight platforms reduces the number of fibers needed for video and data transport between sites, thus reducing the infrastructure costs as well as enabling carriers to add video services on top of their existing OTN metro or long-distance backbone infrastructure.
PacketLight says its modular approach offers optical-to-electrical and electrical-to-optical conversion in a small footprint, without the need of bulky converters. The platforms also offer SNMP-based monitoring and control management software for the conversion process. The systems can map up to 16 multirate bidirectional video services such as DVB-ASI, SD-SDI, or HD-SDI into aggregated 10G or 20G OTU2 within its 1U carrier grade PL-2000 product, for example.
In addition, PacketLight's product line also supports SFP-based pluggable client video interface modules for the commonly used DVB/SDI signals of up to 2.97-Gbps with embedded re-clockers, cable drivers, equalizers, and monitoring capabilities.
Ciena Corp. (NASDAQ: CIEN) says Indiana Fiber Network (IFN) will deploy Ciena’s 5430 Packet-Optical Reconfigurable Switching System (RSS) and OneConnect Intelligent Control Plane software to expand the capacity and service flexibility of its backbone network, and provide assured service delivery.
IFN is a statewide fiber-optic network owned by a consortium of 20 independent telephone companies, and comprises more than 2,400 miles of fiber-optic cable that interconnects eight metro ring networks and 23 points of presence serving more than 3,300 on/near-net locations. Customers include enterprise businesses, government entities, educational and healthcare institutions, as well as independent telephone company members, who use the network for the aggregation and transport of residential local and long-distance calls, Internet access, and video services.
The enhanced OTN-switched network will support the aggregation, transport, and management of voice, video, and data services to business and service provider customers. It will also provide differentiated service offerings and simplified service creation capabilities through point-and-click provisioning, therefore creating bandwidth-on-demand services that can be delivered in minutes, Ciena says.
Ciena’s 5430 is a modular packet-optical platform that will serve as aggregation switches, delivering regionalized OTN and Ethernet traffic to key points in IFN’s network with speed and simplicity (see “Ciena intros modular approach to IP/optical networks”). Equipped with OneConnect control plane software, the 5430 switches will also provide IFN with the ability to automate provisioning and management of its network, while mesh restoration will improve network resiliency and service availability.
Combined with Ciena’s 4200 Advanced Services Platform, which has already been deployed in the network, IFN can support customers’ growing broadband demands and data center connectivity requirements via a scalable, dynamic, and reconfigurable infrastructure, Ciena asserts.
Later this year, IFN also plans to deploy Ciena’s 5410 Reconfigurable Switching System to enable efficient aggregation, grooming, and forwarding of multiple traffic types in metro and regional sites.
Ciena Specialist Services is providing solution installation, turn-up and testing, along with migration services.
“Our recent upgrade is designed to create an intelligent, automated network that can adapt to the diverse service requirements of our customer base – including both member companies and businesses – and be monitored, managed and reprogrammed remotely from our network operations center,” said Jerry Haver, planning and engineering manager, IFN.
Different copper interfaces for video such as SD-SDI, HD-SDI, 3G-SDI and DVB-ASI are all supported by PacketLight's CWDM/DWDM and OTN product family. Additionally, video signals can be mixed with other data and storage traffic such as 1G/10G Ethernet and 1/2/4/8/10G Fibre Channel.
Use of the PacketLight platforms reduces the number of fibers needed for video and data transport between sites, thus reducing the infrastructure costs as well as enabling carriers to add video services on top of their existing OTN metro or long-distance backbone infrastructure.
PacketLight says its modular approach offers optical-to-electrical and electrical-to-optical conversion in a small footprint, without the need of bulky converters. The platforms also offer SNMP-based monitoring and control management software for the conversion process. The systems can map up to 16 multirate bidirectional video services such as DVB-ASI, SD-SDI, or HD-SDI into aggregated 10G or 20G OTU2 within its 1U carrier grade PL-2000 product, for example.
In addition, PacketLight's product line also supports SFP-based pluggable client video interface modules for the commonly used DVB/SDI signals of up to 2.97-Gbps with embedded re-clockers, cable drivers, equalizers, and monitoring capabilities.
Ciena Corp. (NASDAQ: CIEN) says Indiana Fiber Network (IFN) will deploy Ciena’s 5430 Packet-Optical Reconfigurable Switching System (RSS) and OneConnect Intelligent Control Plane software to expand the capacity and service flexibility of its backbone network, and provide assured service delivery.
IFN is a statewide fiber-optic network owned by a consortium of 20 independent telephone companies, and comprises more than 2,400 miles of fiber-optic cable that interconnects eight metro ring networks and 23 points of presence serving more than 3,300 on/near-net locations. Customers include enterprise businesses, government entities, educational and healthcare institutions, as well as independent telephone company members, who use the network for the aggregation and transport of residential local and long-distance calls, Internet access, and video services.
The enhanced OTN-switched network will support the aggregation, transport, and management of voice, video, and data services to business and service provider customers. It will also provide differentiated service offerings and simplified service creation capabilities through point-and-click provisioning, therefore creating bandwidth-on-demand services that can be delivered in minutes, Ciena says.
Ciena’s 5430 is a modular packet-optical platform that will serve as aggregation switches, delivering regionalized OTN and Ethernet traffic to key points in IFN’s network with speed and simplicity (see “Ciena intros modular approach to IP/optical networks”). Equipped with OneConnect control plane software, the 5430 switches will also provide IFN with the ability to automate provisioning and management of its network, while mesh restoration will improve network resiliency and service availability.
Combined with Ciena’s 4200 Advanced Services Platform, which has already been deployed in the network, IFN can support customers’ growing broadband demands and data center connectivity requirements via a scalable, dynamic, and reconfigurable infrastructure, Ciena asserts.
Later this year, IFN also plans to deploy Ciena’s 5410 Reconfigurable Switching System to enable efficient aggregation, grooming, and forwarding of multiple traffic types in metro and regional sites.
Ciena Specialist Services is providing solution installation, turn-up and testing, along with migration services.
“Our recent upgrade is designed to create an intelligent, automated network that can adapt to the diverse service requirements of our customer base – including both member companies and businesses – and be monitored, managed and reprogrammed remotely from our network operations center,” said Jerry Haver, planning and engineering manager, IFN.
Monday, June 4, 2012
LUS Fiber launches 1-Gbps service over FTTP network/LION2 Indian Ocean submarine cable now in service
Unless you live someplace like Chattanooga, TN, the folks in Lafayette, LA, can get faster Internet service than you can. LUS Fiber, the telecommunications division of Lafayette Utilities System, has launched a symmetrical 1-Gbps Internet service over its community-owned fiber-to-the-premises (FTTP) network.
Like the 1-Gbps service offered in Chattanooga (see “EPB Fiber Optics offers 1 Gigabit broadband in Chattanooga via GPON”), the LUS Fiber offering is targeted more at local businesses than homes.
“We have raised the bar in order to make our community a place where technology companies want to locate,” says Joey Durel, city-parish president of Lafayette.
LUS built is FTTP network after overcoming intense opposition from the incumbent telco and cable operator that extended to the Louisiana Supreme Court (see “FTTH Council joins LUS fight in Supreme Court”). Construction on the network began in 2008 and completed in 2010.
“Gigabit service from LUS Fiber is one of the most robust Internet offerings on the market today,” says Terry Huval, director of Lafayette Utilities System and LUS Fiber. “We built this community network with a promise to the people of Lafayette that we will work hard to provide them with new opportunities through this unique, state-of-the-art fiber technology…and that’s just what we’ve done.”
The Lower Indian Ocean Network 2 (LION2) undersea fiber-optic cable system is now in service, according to France Telecom-Orange. LION2 adds Kenya to the LION network.
The original LION cable system, completed in 2009, links Madagascar to the global broadband network via the Réunion and Mauritius islands. LION2 adds connectivity to Kenya via the island of Mayotte.
The LION2 consortium includes France Telecom-Orange; France Telecom subsidiaries Mauritius Telecom, Orange Madagascar, and Telkom Kenya; and Emtel Ltd. of the Republic of Mauritius and Société Réunionnaise du Radiotéléphone of Réunion Island.
Through its landing station at Kaweni (Mamoudzou), LION2 will provide Mayotte, for the first time, with access to a broadband internet network. In Kenya, the LION2 cable is connected through a new landing station that has been built at Nyali, close to Mombasa.
In addition to providing Internet access to the region, the new cable also provides an alternative route for passing secure broadband transmissions through Europe and Asia for all African countries in which the France Telecom-Orange Group is located, says the consortium member.
The construction of the LION2 cable required about 57 million euros, about 38 million euros of which will come from France Telecom SA and its subsidiaries.
Like the 1-Gbps service offered in Chattanooga (see “EPB Fiber Optics offers 1 Gigabit broadband in Chattanooga via GPON”), the LUS Fiber offering is targeted more at local businesses than homes.
“We have raised the bar in order to make our community a place where technology companies want to locate,” says Joey Durel, city-parish president of Lafayette.
LUS built is FTTP network after overcoming intense opposition from the incumbent telco and cable operator that extended to the Louisiana Supreme Court (see “FTTH Council joins LUS fight in Supreme Court”). Construction on the network began in 2008 and completed in 2010.
“Gigabit service from LUS Fiber is one of the most robust Internet offerings on the market today,” says Terry Huval, director of Lafayette Utilities System and LUS Fiber. “We built this community network with a promise to the people of Lafayette that we will work hard to provide them with new opportunities through this unique, state-of-the-art fiber technology…and that’s just what we’ve done.”
The Lower Indian Ocean Network 2 (LION2) undersea fiber-optic cable system is now in service, according to France Telecom-Orange. LION2 adds Kenya to the LION network.
The original LION cable system, completed in 2009, links Madagascar to the global broadband network via the Réunion and Mauritius islands. LION2 adds connectivity to Kenya via the island of Mayotte.
The LION2 consortium includes France Telecom-Orange; France Telecom subsidiaries Mauritius Telecom, Orange Madagascar, and Telkom Kenya; and Emtel Ltd. of the Republic of Mauritius and Société Réunionnaise du Radiotéléphone of Réunion Island.
Through its landing station at Kaweni (Mamoudzou), LION2 will provide Mayotte, for the first time, with access to a broadband internet network. In Kenya, the LION2 cable is connected through a new landing station that has been built at Nyali, close to Mombasa.
In addition to providing Internet access to the region, the new cable also provides an alternative route for passing secure broadband transmissions through Europe and Asia for all African countries in which the France Telecom-Orange Group is located, says the consortium member.
The construction of the LION2 cable required about 57 million euros, about 38 million euros of which will come from France Telecom SA and its subsidiaries.
Monday, May 28, 2012
NeoPhotonics adds 40-km, 80-km SFP+ optical transceivers/Page Not Found
NeoPhotonics Corp. (NYSE: NPTN) has added longer-reach SFP+ transceivers to its line of modules that meet 40-km (ER) and 80-km (ZR) reach requirements and support various communication protocols. The new SFP+ optical transceiver modules complement NeoPhotonics existing 6-Gbps SFP+ transceivers for Common Public Radio Interface (CPRI) and 10-Gbps SFP+ modules for 10 Gigabit Ethernet and OC-192/STM-64 SONET/SDH transport.
SFP+ transceivers without integrated CDR are designed to support 10-Gigabit Ethernet transport and comply with IEEE 802.3-2005 and 802.3-2008. Versions with an integrated CDR support OC-192/STM-64 SONET/SDH and comply with the ITU-T Recommendation G.709 for Optical Transport Network (OTN) at the OTU2 line rate.
All of the company’s transceivers are designed to meet Telcordia GR-468 CORE qualification requirements and cover the extended operating temperature range of -5 to +85ºC (E-Temp), NeoPhotonics asserts. Both RoHS5 and RoHS6 versions are available as well. The SFP+ ER and ZR transceivers are available in sample quantities.
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SFP+ transceivers without integrated CDR are designed to support 10-Gigabit Ethernet transport and comply with IEEE 802.3-2005 and 802.3-2008. Versions with an integrated CDR support OC-192/STM-64 SONET/SDH and comply with the ITU-T Recommendation G.709 for Optical Transport Network (OTN) at the OTU2 line rate.
All of the company’s transceivers are designed to meet Telcordia GR-468 CORE qualification requirements and cover the extended operating temperature range of -5 to +85ºC (E-Temp), NeoPhotonics asserts. Both RoHS5 and RoHS6 versions are available as well. The SFP+ ER and ZR transceivers are available in sample quantities.
The page you requested could not be found.
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FTTX
Test & Measurement
Equipment Design
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You can also view and interact with the following content:
The Lightwave Channel
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Monday, May 21, 2012
Oplink unveils suite of rugged SFP+ transceivers
Components and subsystems vendor Oplink Communications, Inc. (NASDAQ:OPLK) has announced the availability of a full suite of SFP+ transceiver products, including low-power 80-km reach, CWDM, and DWDM versions.
Oplink says these products have been designed for lower power consumption and wider operational temperature ranges to enable 10-Gbps deployment in high-density systems and in the challenging environments found in data centers, access aggregation, and mobile backhaul applications.
The main features of Oplink's new portfolio of SFP+ transceivers are:
Maximum of 1.5-W power consumption supporting 10-Gbps applications reaching up to 80 km
DWDM with 46 wavelength channels supporting up to 80-km uncompensated links, or longer distances assisted with dispersion compensation and optical amplification
Operational temperature range from -40 to 85 degrees C for all SFP+ products in the portfolio
"The release of our suite of SFP+ transceivers dovetails with the optical networking trend of deploying higher bandwidth closer to end users, where high-density solutions and operations with greater temperature ranges are required," said Dr Rang-Chen Yu, vice president of business development at Oplink. "Our rugged and power-saving SFP+ products have been deployed in a wide range of applications, such as data center switch connectivity, service router WAN interface, access aggregation, and wireless backhaul networks. With today's announcement, we are pleased to now offer customers our next-generation, rugged SFP+ transceiver designs."
The SFP+ transceiver products are available to order now, says Oplink. The C-temperature (-5 to 70 degrees C) versions of these products are currently in full production, and all of the industrial-temp (-40 to 85 degrees C) versions are expected to complete qualification and begin production shipment by April.
Oplink will showcase its complete line of SFP+ transceiver products at OFC/NFOEC on March 6—8, 2012, in Los Angeles, CA, booth #1717.
Oplink says these products have been designed for lower power consumption and wider operational temperature ranges to enable 10-Gbps deployment in high-density systems and in the challenging environments found in data centers, access aggregation, and mobile backhaul applications.
The main features of Oplink's new portfolio of SFP+ transceivers are:
Maximum of 1.5-W power consumption supporting 10-Gbps applications reaching up to 80 km
DWDM with 46 wavelength channels supporting up to 80-km uncompensated links, or longer distances assisted with dispersion compensation and optical amplification
Operational temperature range from -40 to 85 degrees C for all SFP+ products in the portfolio
"The release of our suite of SFP+ transceivers dovetails with the optical networking trend of deploying higher bandwidth closer to end users, where high-density solutions and operations with greater temperature ranges are required," said Dr Rang-Chen Yu, vice president of business development at Oplink. "Our rugged and power-saving SFP+ products have been deployed in a wide range of applications, such as data center switch connectivity, service router WAN interface, access aggregation, and wireless backhaul networks. With today's announcement, we are pleased to now offer customers our next-generation, rugged SFP+ transceiver designs."
The SFP+ transceiver products are available to order now, says Oplink. The C-temperature (-5 to 70 degrees C) versions of these products are currently in full production, and all of the industrial-temp (-40 to 85 degrees C) versions are expected to complete qualification and begin production shipment by April.
Oplink will showcase its complete line of SFP+ transceiver products at OFC/NFOEC on March 6—8, 2012, in Los Angeles, CA, booth #1717.
Sunday, May 13, 2012
Radio direction finding
The first system of radio navigation was the Radio Direction Finder, or RDF. By tuning in a radio station and then using a directional antenna to find the direction to the broadcasting antenna, then using triangulation, two such measurements can be plotted on a map where their intersection is the position. Commercial AM radio stations can be used for this task due to their long range and high power, but strings of low-power radio beacons were also set up specifically for this task.
Early RDF systems normally used a loop antenna, a small loop of metal wire that is mounted so it can be rotated around a vertical axis. At most angles the loop has a fairly flat reception pattern, but when it is aligned perpendicular to the station the signal in one side cancels the signal in the other, producing a sharp drop in reception known as the "null". By rotating the loop and looking for the angle of the null, the relative bearing of the station can be determined. Loop antennas can be seen on most pre-1950s aircraft and ships.
Early RDF systems normally used a loop antenna, a small loop of metal wire that is mounted so it can be rotated around a vertical axis. At most angles the loop has a fairly flat reception pattern, but when it is aligned perpendicular to the station the signal in one side cancels the signal in the other, producing a sharp drop in reception known as the "null". By rotating the loop and looking for the angle of the null, the relative bearing of the station can be determined. Loop antennas can be seen on most pre-1950s aircraft and ships.
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