Radial SP8T Switch
The model MSR-8DR-STD options 50M105, 3SS, 45060, is a reflective SP8T switch, that is surface-mountable, miniature and slim in size. It works from 10 MHz to 5 GHz. Insertion loss is < 3 dB at 5 GHz. Amplitude is ±0.5 dB and phase is ±5° between ports from 10 MHz to 5 GHz; SWR is 1.5. Isolation is > 90 dB at 10 MHz, > 75 dB at 2 GHz and > 65 dB at 5 GHz. Switching speed is < 200 ns delay on and < 250 ns delay off. Supply voltages are +5 V at 3 mA and -5 V at 47 mA. Weight: < 2.5 ounces typical. Size: 1.5" x 0.4".
American Microwave Corp., Frederick, MD (301) 662-4700. Circle No. 216
Millimeter Waveguide Coupler
The WR15 millimeter waveguide coupler device performs over the 59 to 62 GHz frequency band and has a maximum insertion loss of 0.7 dB. It has an SWR of 1.10, 12 dB coupling and a coupling flatness of < ±0.3 dB. Other frequencies, waveguide sizes and coupling values are available. This can also be supplied as a space qualified part.
Channel Microwave Corp., Camarillo, CA (805) 482-7280. Circle No. 217
The CCDP-452-1 AMPS B-band duplexer is designed for 800 W CW and up to 20 carriers at 40 W each PIP. Good isolation performance coupled with low loss makes this design ideal for cell sites located in high density traffic areas. This product is available from stock in a standard package size of 9.2" x 8.0" x 3.4". Mounting options such as 19" rack mountable and ladder suspension are available as well as other custom configurations. An outdoor sealant option is available upon request.
ClearComm Technologies LLC, Salisbury, MD (410) 860-0050. Circle No. 218
This optical SMA connector is primarily for use with plastic fiber. The new series is suitable for 1 mm core size plastic fiber with a 2 mm jacket outer diameter. This cost-effective solution assures high precision and stability of mechanical and optical characteristics. Connectors are easily attached to cable with commercially available crimp tools.
Compel Electronics Inc., Ashland, MA (508) 881-9293. Circle No. 219
3.5 GHz Duplexer
The model EWT-21-0052A is a 3.5 GHz duplexer that has a 28 MHz passband for both receive and transmit channels. This duplexer is designed to operate over various center frequencies. The passband insertion loss is less than 1.25 dB over the operating temperature range of -45° to +80°C. The typical passband SWR is 1.4 with Rx-to-Tx isolation > 75 dB. This duplexer also exhibits > 70 dB rejection up to 11 GHz. This model is rated to operate at 20 W. Size: 3.2" x 2.25" x 0.88".
Eastern Wireless TeleComm Inc., Salisbury, MD (410) 749-3800. Circle No. 220
The Quick-lock N (QN) size connector requires a low mating force of approximately 30 N, which results in quicker mating time. This is due to the locking mechanism that snaps closed in a single step. Pulling back the de-coupling sleeve opens the snap ring of the mating mechanism, allowing for quick de-mating with a force of 30 N. This device can be used in a wide variety of applications such as radio base stations, antenna systems, and test and measurement, primarily all applications where medium or high power has to be transmitted with low loss.
HUBER+SUHNER, Herisau, Switzerland +41 (0) 71 353 41 11. Circle No. 221
Public Safety Notch Filter
The WSN-00118 filter is designed for SMR services to guard against spectral regrowth into public safety bands. It provides a passband of DC to 865 MHz with low insertion loss of 0.2 dB maximum from DC to 849 MHz and 1.0 dB maximum from 849 to 865 MHz, while offering significant rejection of 45 dB minimum from 866 to 869 MHz. The product specification calls for passband return loss of 15 dB minimum.
K&L Microwave Inc., Salisbury, MD (410) 749-2424. Circle No. 222
The M9-3040 2nd and 4th LO-harmonic mixer covers 30 to 40 GHz (7.5 to 20 GHz LO) with a DC to 1000 MHz IF. Designed for fiber-optic clock-recover/acquisition, the M9-3040 is a unique harmonic mixer design, available in both open carrier and 2.92 mm connectorized outlines. Local oscillator drive is +10 to +12 dBm. Typical conversion loss is 20 dB for both 2nd and 4th harmonic of the LO mixing.
Marki Microwave Inc., Morgan Hill, CA (408) 778-4200. Circle No. 223
The CK-10N directional coupler provides ±0.5 dB flat coverage from 700 to 2700 MHz. It covers all the cellular wireless frequency bands used for in-building applications. This directional coupler series is available in 6 and 10 dB coupling values and will soon be expanded to include 15, 20 and 30 dB values. This bandwidth has been made possible through the use of tapered design techniques which can carry powers up to 200 W. Such units are most commonly used to unequally split wireless carriers to a secondary antenna feed or distribution cable.
Microlab/FXR, Livingston, NJ (973) 992-7700. Circle No. 224
Low Pass Filter
The FL0005M1 surface-mount low pass filter is ruggedly constructed and durable. It has an insertion loss of less than 1 dB from DC to 5.0 MHz, and 3 dB insertion loss at 5.8 MHz nominal. This customizable filter has rejection greater than 20 dBc at 8 MHz and a rejection greater than 40 dBc at 10 to 200 MHz. It is economically priced for high volume and short lead times. This compact and competent filter has bi-directional 0.050" tabs for SMT applications. Size: 0.25" x 0.38" x 0.75".
Microwave Circuits Inc., Washington, DC (202) 829-3030. Circle No. 225
Two Bit Phase Shifter
The model PS-360-90-2-202F is a temperature compensated, two bit, 360° digital phase shifter. It operates from 1.7 to 2.3 GHz having phase shifts of 45°, 90°, 135°, 270°, 360° with phase error of 7° over the frequency band (0.5 to 20 GHz units are also available). This unit is TTL controlled and operates on +5 VDC at 50 mA and -5 VDC at 50 mA. Size: 2.0" x 2.0" x 0.50".
Planar Monolithics Industries Inc., Frederick, MD (301) 631-1579. Circle No. 226
Bessel Low Pass Filters
The 4th order tubular Bessel low pass filters are available with 3 dB cutoffs at up to 2x cutoff of its LB series. Computer design and tubular construction allow maintenance of good delay characteristics with reasonable rejection while extending a 3 dB cutoff and eliminating unwanted spurious response. These filters are primarily used on lightwave receivers to reduce the impact of higher order distortion and noise. These high frequency filters are essential for high bit rate applications.
RLC Electronics Inc., Mt. Kisco, NY (914) 241-1334. Circle No. 227
High Frequency Resistors
These high frequency chip resistors are compact, lightweight designs that are ideal for use in RF and microwave applications. The components are available in 14 standard case sizes: 0402 thru 3838. These high frequency resistors are available with single surface or wrap around terminations, and a variety of termination materials for solder mount epoxy bond, or wire bond applications. Construction material consists of either an alumina or beryllia body with a proprietary resistor element for optimum performance. The devices are optimized for 50 characteristic impedance using special manufacturing techniques to reduce SWR. Power ratings for the resistors range from 50 mW up to 200 W and a low return loss up to 20 GHz.
State of the Art Inc., State College, PA (800) 458-3401. Circle No. 228
The model KDS-10-225 and KDS-20-225 directional couplers offer high power of 10 and 20 dB. They are ideal for applications in high power antenna forward signal monitoring and high power SWR signal monitoring bridge. Both models are designed to handle up to 50 W of forward power over the operating temperature range of -55° to +85°C. The operating frequency range is within 225 to 400 MHz. The typical performance characteristics include insertion loss of 0.2 dB, directivity of 23 dB and SWR of 1.2 on the input and output ports. Price: $65.95 (1-9). Delivery: available from stock.
Synergy Microwave Corp., Paterson, NJ (973) 881-8800. Circle No. 229
Ultra-miniature CSP SAW Filters
Using chip-scale packaging specifically to address the miniaturization and performance re-quirements for new generations of mobile phones, these RF SAW filters support all the major standards: GSM850/900/1800/1900, CDMA450, CDMA2000, PCS, W-CDMA, GPS, 802-11 b/g and Bluetooth. The result is that for each device, the package size is just 2.0 x 1.4 x 0.82 mm maximum. Key features include compatibility with lead-free (high temperature) solder reflow, while achieving high reliability against moisture, temperature, mechanical vibrations and shocks. Also, the devices offer a balanced output and improve signal sensitivity.
Temex, Paris, France +33 (0) 1 46 90 23 33. Circle No. 261
The model I1920AJ drop-in isolator has an integrated coupler that can be used in PCS 1900, GSM and UMTS base station applications. This model is primarily used in power combiners, duplexers and amplifiers for base station usage. The I1920AJ isolator has an operating frequency range of 1930 to 1990 MHz, while providing return loss of 20 dB minimum, isolation at 21 dB minimum and insertion loss at 0.35 dB maximum. This single junction unit includes an integrated coupler, a high torque SMA connector, integrated termination and has good performance specifications configurable to customer specifications.
Trak Microwave Corp., Tampa, FL (813) 901-7200. Circle No. 230
Fixed Attenuator Pads
These high performance 50 , 2 W fixed attenuator pads are designed for precision control and are offered in a wide choice of values and increments. Featuring high accuracy (±0.3 dB or 1.5 percent) and a wide frequency range (DC to 2 GHz and DC to 4 GHz). Any value is available between 0.5 and 40 dB. The new model LFP-50 series is available with a choice of SMA, N, TNC or BNC connectors. Custom design and configurations are also available. Delivery: stock to four weeks.
Trilithic Inc., Indianapolis, IN (800) 344-2412. Circle No. 231
RF Coaxial Connectors
This line of high frequency, push-on blind mate RF coaxial connectors are subminiature versions of BMA connectors for applications where space is limited. The BMMA series connectors feature high integrity and push-on blind mate interfaces. The inner conductors and insulators of these subminiature connectors are mechanically captivated, rather than epoxied, to help prevent RF leakage. Suitable for attachment to semi-rigid cable, the BMMA series connectors are designed for DC to 28 GHz applications, provide 50 impedance, 675 VRMS dielectric withstanding voltage, 5000 megohms min. insulation resistance and -90 dB RF leakage. They have 303 SST bodies, beryllium-copper center contacts, PTFE insulators and operate over a -65° to +125°C range. Price: $28.95.
TRU Corp., Peabody, MA (800) 262-9878. Circle No. 232
This UMTS duplexer features passband frequencies of 1920 to 1980 MHz and 2110 to 2170 MHz. The insertion loss is 0.8 dB maximum and the duplexer exhibits a high out-of-band rejection of 80 dB minimum. Also, different connectors and specifications are available upon request.
Universal Microwave Technology Inc., Taiwan, ROC +886-2-2698-9969. Circle No. 233
2 kW Circulators
The CT-1510-S special series of ferrite circulators is rated at 2 kW average/CW and 10 kW peak power for use in the digital and HDTV UHF television bands. Four units cover the entire 470 to 860 MHz spectrum. These units exhibit less than 0.25 dB loss while providing 20 dB min. isolation and 1.25 max. SWR. EIA 7/8" connectors are used for the main line power and type N or DIN 7/16 for the load port. Other frequency ranges can also be supplied with similar specs, including VHF channels 7 to 13 (174 to 216 MHz).
UTE Microwave Inc., Asbury Park, NJ (732) 922-1009. Circle No. 234
Multilayer Ceramic Inductors
The Dale ILC-0402 series multilayer high frequency ceramic inductors are aimed at signal shaping and RF filtering applications in a wide range of electronic systems. Target end products include cell phones, pagers, keyless entry systems, wireless and wireline networks, remote controls, high end video processing equipment, set-top boxes and cable modems. Standard inductance options for the ILC-0402 series range from 1 to 47 nH. Available tolerances are ±0.3 nH for devices rated from 1 to 5.6 nH, and ±5 or ±10 percent for devices rated at 6.8 nH and above. Maximum DC resistance (DCR) ranges from 0.12 to 1.30 depending on inductance. Size: 1 x 0.5 x 0.5 mm. Price: $0.05 (10,000). Delivery: stock to six weeks.
Vishay Intertechnology Inc., Malvern, PA (610) 644-1300. Circle No. 235
These MMIC Quad-MOSFET mixers include integral RF and LO baluns within a 3 x 3 mm, six-pin, DFN, surface-mount package. An external IF balun can be used to accommodate single-ended operation if a differential signal is not desired. These passive mixers do not require biasing and as such have good noise figure of 8 dB. The intended application is up/down conversion with a low side LO for receivers, transmitters, gain control, modulators or demodulators. Key features include +13 dBm LO drive level, +27 dBm IIP3, 7.5 dB conversion loss and good port-to-port isolation. The mixers will accommodate higher LO drive levels up to +20 dBm with improved performance.
WJ Communications Inc., San Jose, CA (800) WJ1-4401. Circle No. 236
The model 4061 is a 1.85 to 2.17 GHz, 200 W solid-state amplifier that covers the PCS and UMTS bands. The model 4061 was designed for the wireless test and measurement market. It is well suited for both RF power component and system susceptibility testing. With a P1dB power of 160 W and small signal gain of 53 dB, this load tolerant amplifier is available in a rack mount case. If required, the lower frequency can be extended down to 1.80 GHz to cover the DCS band.
Ophir RF, Los Angeles, CA (310) 306-5556. Circle No. 237
InGaP Gain Blocks
The SBA-4086 and SBA-5086 devices are high linearity, robust InGaP HBT gain block amplifiers which are suitable for wireless infrastructure applications. Designed with Darlington topology, the parts provide Class 1C 1000v ESD protection. The SBA series, packaged in the low cost plastic Micro X (86) style package, has low thermal resistance (102°C/W) and good IP3 performance (> 33.5 dBm at 1950 MHz).
Sirenza Microdevices Inc., Sunnyvale, CA (408) 616-5400. Circle No. 238
High Power Amplifiers
The model AHP-94022315-01 and the AHP-94022624-01 operate in the 93 to 95 GHz frequency range, and provide a minimum of 15 and 24 dB gain with saturated output power of 250 and 400 mW, respectively. The amplifiers operate at +8 VDC and typically draw 1.0 A current for the 250 mW model and 2.0 A for the 400 mW model. The input and output connectors of the amplifiers are standard WR-10 waveguide with UG387/U Mod flange.
WiseWave Technologies Inc., Torrance, CA (310) 371-5833. Circle No. 239
Low Profile Microwave Antennas
These ValuLine® terrestrial microwave antennas have a 1.8 meter diameter single and a dual polarized low profile radiator. Available for the 13, 15 and 18 GHz frequency bands, these antennas are a robust, durable and cost-effective solution for point-to-point communications. Antennas such as these are typically used for cellular backhaul, private user networks, or any other application needing reliable microwave communications.
Andrew Corp., Orland Park, IL (800) 255-1479. Circle No. 240
The latest release of Microwave Studio® version 4.2 provides new functionality in its service packs. These functionalities include: numerous improvements in the calculation of farfields, including Ludwig Transformations and Time Domain probes for antenna designers; model waveguide ports that can be defined inside the calculation domain; new general Voxel import that allows engineers to input or create their own models for SAR calculations in addition to using the commercially available Anatomical Data Set "HUGO"; and a new automatic post-processing scheme to enable easy, versatile evaluation of parameter studies.
Computer Simulation Technology, Darmstadt, Germany +49 (0) 6151 7303-0. Circle No. 242
The Pulsonix PCB version 2.0 design software suite includes over 70 new features above the preceding version 1.2. Features include: true instanced multi-level hierarchy in schematics; electrical rules checking in schematics with user definable rules; new report maker with IF, ELSE, conditional features; breakouts in PCB - fan out/fan in; jumpers in PCB; user definable PAD shapes; associative parts; and new cost option chip on board with movable bond pads, die pads and bonds wire.
LPKF Laser & Electronics, Wilsonville, OR (503) 454-4233. Circle No. 243
This series of phase-locked dielectric resonator oscillators (PLDRO) was primarily designed for use in LMDS telecommunication systems. It operates at a frequency of 11.48 GHz and provides dual power outputs of 15 dBm each, with phase noise values of -80 dBc/1 kHz and -90 dBc/10 kHz. The PLDROs utilize SMA connectors, work off a 15 V supply and have an operating temperature between -30° and +85°C.
Elsys Electronic Systems, Poltava, Ukraine +38 (0532) 505919. Circle No. 245
The FVS25AXT is a 3.3 V, low profile, surface-mount VCXO with a pullability of ±100 ppm and a frequency range of 2 through 52 MHz. The frequency stability of this oscillator is ±50 ppm, and standard operating temperature is -10° to 70°C, with a storage temperature of -40° to 85°C. Output symmetry is 40 to 60 percent at 50 percent Vdd over the frequency range. The FVS25AXT is ideal for wireless, portable and handheld applications where size is critical. Size: 5.0 x 3.2 x 1.2 mm. Price: $2.25 (10,000). Delivery: eight weeks ARO.
Fox Electronics, Fort Myers, FL (888) GET-2-FOX. Circle No. 246
Low Noise MMIC VCO
The HMC384LP4 is a GaAs InGaP HBT MMIC VCO with integrated resonator, negative resistance device, varactor diode and buffer amplifier covering applications from 2.05 to 2.25 GHz. The HMC384LP4 is ideally suited for cellular/3G and broadband wireless data systems applications. This MMIC VCO requires no external components, consumes only 35 mA from a single supply of +3 V and provides +3.5 dBm buffered output power. The low phase noise of -112 dBc/Hz at 100 kHz offset is good over temperature, shock, vibration and process due to the monolithic structure of the oscillators. Size: 4 x 4 mm.
Hittite Microwave Corp., Chelmsford, MA (978) 250-3343. Circle No. 247
C-band Frequency Synthesizer
The MFS compact devices employ a single module design implemented with CMOS, ASICs, advanced MMICs and a dedicated microprocessor. A C-band synthesizer with 125 or 1 kHz step, up to 1.2 GHz bandwidth and an integrated PLDRO requires only 8 W of DC power. Typical frequencies are: 4.5 to 5.5 GHz, 5.1 to 5.7 GHz, 6.5 to 7.6 GHz, 7.2 to 7.7 GHz. The synthesizers offer a phase noise of -110 dBc offset 100 kHz from 2.5 GHz as well as guaranteed zero phase hits over temperature. Size: 7.7" x 5.5" x 0.73".
Elcom Technologies Inc., Rockleigh, NJ (201) 767-8030. Circle No. 244
The PTS 6400 frequency synthesizer was designed for applications requiring direct frequency synthesis up to 6.4 GHz. This synthesizer features resolution of 1 Hz, fast frequency switching speed and high spectral purity. The output level is -3 to +7 dBm. At full output level the discrete spurious spec is -60 dBc from 1 to 3200 MHz and -55 dBc from 3200 to 6400 MHz. Phase noise is -122 dBc/Hz (10 kHz offset) at 1 GHz. Size: 19" x 5-1/4" x 18". Price: $15,000.
Programmed Test Sources Inc., Littleton, MA (978) 486-3400. Circle No. 249
Phase Locked Sources
The BCO series phase locked sources offer good phase noise and spurious performance. Available in frequencies from 500 MHz to 14 GHz, they operate from either an external reference or internal TXXO with stability as low as 1 PPM. Flexible internal DC regulators allow operating DC or 5.2 to 15 VDC. Size: 2.25" x 2.25" x 0.55".
MITEQ Inc., Hauppauge, NY (631) 436-7400. Circle No. 248
The SMV0206L is a voltage-controlled oscillator primarily introduced for the digital enhanced cordless telecommunications (DECT) market. It is designed for applications where power consumption is a tantamount concern. The SMV0206L generates frequencies between 200 and 212 MHz within 0.5 to 2.25 VDC of control voltage, and is primed for tough outdoor application by operating over an extensive temperature range of -20° to 70°C. This device exhibits a clean spectral signal of -98 dBc/Hz, typically at 10 kHz from the carrier, and attenuates the second harmonic to better than -10 dBc. Size: 0.30" x 0.30" x 0.08". Price: $15.95 (5). Delivery: stock to four weeks.
Z-Communications Inc., San Diego, CA (858) 621-2700. Circle No. 251
Five-slot Portable Mainframe
The CT-310A is a high performance portable chassis designed with transportability and modularity in mind. Supplying over 500 W of total usable power, the CT-310A is equally at home in the field or in the laboratory. A pressurized airflow system provides good cooling, increased MTBF and ultimately results in decreased down time. Additionally, the modular power supply and fan assembly simplify maintenance operations. Power supply voltages are monitored and displayed via front panel LEDs, and the supply voltages are also available for external circuits. Weight: < 15 lbs. Pricing: $3600. Delivery: stock to four weeks ARO.
VXI Technology, Irvine, CA (949) 955-1VXI. Circle No. 253
I&Q Vector Modulator
The model M2P-83N-5MA is a 360°, 50 dB high dynamic range PIN diode I&Q vector modulator that operates from 17.9 to 21.1 GHz. This device offers simultaneous phase and amplitude control. Across the entire band the total phase error is ±10° and amplitude error is ±0.5 to 40 dB. The SWR is better than 1.8. The device demonstrates a linear control input slope with output voltage. With a monotonic performance this device is digitally controlled via two sets (I&Q) of 12 bit TTL compatible binary logic inputs and the switching speed less than 500 ns. The unit is packaged to form, fit and function as an industry recognized standard.
G.T. Microwave Inc., Randolph, NJ (973) 361-5700. Circle No. 252
FM-CW Radar Transceiver
The FM-CW radar system includes a highly sensitive heterodyne configuration with better then 10 dB SSB noise figure, and homodyne configurations designed specifically for cost-driven applications. These designs are based on the proprietary active frequency multiplier technology, which facilitates multiple architecture and frequency configurations from the same basic building blocks. Size: 400 x 270 x 35 mm.
ELVA-1 Ltd., Gilland Electronics Inc., Los Gatos, CA (800) 480-3391. Circle No. 254
Multi-technology RF Scanner
The Seven.Five multi-band, multi-technology RF scanner is primarily for wireless field-test applications. Capable of lightning-fast scans (up to 3000 channels per second) in multiple frequency bands, with multiple technologies, the Seven.Five scanner decodes DVCC, BSIC and PN decoding simultaneously. The scanner offers spectrum analyzer-type measurements and full baseband decoding for GSM 850/900/1800/1900, GPRS, IS-136, CDMA2000 and WCDMA. The scanner consumes less than 7 W and has a network-locked frequency accuracy of ±0.1 ppm. The scanner has full ESD protection, is CE Mark compliant and includes external USB connections. Price: $10,000. Delivery: six to eight weeks ARO.
Comarco Wireless Test Solutions, Irvine, CA (949) 599-7400. Circle No. 256
RF Production Probe Card
The Pyramid™ Probe Card is a RF multi-device test production probe card. The probe card allows wafer testing of multiple RF semiconductor wafers in production simultaneously. It has proved effective in applications such as WLAN Blue Tooth™ and cellular/PCS devices. The Pyramid Probe card increases the capability of expensive capital test equipment used in semiconductor manufacturing lines in fabs, design and test houses. Pyramid Probe Cards are compatible with all brands of RF ATE equipment.
Cascade Microtech Inc., Beaverton, OR (800) 550-3279. Circle No. 257
Selective RF Receiver
The C.A 47 is a selective RF receiver, which linked to an odometer and a GPS system can provide measurements for electric field mapping in cellular radiotelephony, radio broadcasting, television and EMC measurement laboratories. It is capable of measuring the levels picked up by an antenna over a wide dynamic range of 0.1 mV/m to 300 mV/m. Its selectivity can be adjusted between 1 kHz and 1 MHz, covering virtually all current telecommunications networks operating over the full range of frequencies between 25 MHz and 2.5 GHz.
Chauvin Arnoux, Paris, France +33 0144 85 4485. Circle No. 258
Systems Design Guide
These test systems are designed to specifically meet customer's individual requirements. The systems are offered in DC through to 18 GHz with a large number of test systems designed around the wireless industry. All control options are available including RS-232C, GPIB/IEEE488, RS-485, RS-422 and Ethernet.
JFW Industries Inc., Indianapolis, IN (877) 887-4JFW. Circle No. 255
Frequency and Phase Difference Meter
The A7-A (analogue) is a high resolution frequency and phase comparator which enables fast comparisons and adjustment between frequency standards and oscillators. Close in phase noise to low levels of measurement is featured on the A7-M (Metrology) version. The A7-A version of the national lab A7-M comparator enables 1x10-13 resolution of the frequency difference between two standards. No PC is required with the A7-A. The A7-A has noise reduction filters which are selectable by simple front panel control as is resolution ranging from 1x10-6 to 1x10-13. The A7-A may be upgraded to the A7-M to increase resolution by 1000x with the addition of a PC, time interval counter card and Stable32 software. This arrangement forms a National Laboratory level metrology system suitable for leading research projects with 1x10-16 resolution.
Quartzlock, Devon, England +44 (0) 1803 862062. Circle No. 260