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THE ‘LOGI’
LOG PERIODIC
ANTENNA
Ramsey Electronics Model No. LPY2
Constructed on rugged FR-4 material, it requires no tuning and
has no fragile antenna elements to break or twist! Covers the
entire 900 to over 2,500 MHz frequency range.
Why settle for any old antenna… this little baby “compresses”
the signal into a powerful beam that is 4 times more powerful in
the direction you desire!
• Easy hookup to your Receiver or Transmitter
• Small thin size with excellent broadband p
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RAMSEY TRANSMITTER KITS • FM100B Professional FM Stereo Transmitter • FM25B Synthesized Stereo FM Transmitter • MR6 Model Rocket Tracking Transmitter • TV6 Television Transmitter RAMSEY RECEIVER KITS • FR1 FM Broadcast Receiver • AR1 Aircraft Band Receiver • SR2 Shortwave Receiver • SC1 Shortwave Converter RAMSEY HOBBY KITS • SG7 Personal Speed Radar • SS70A Speech Scrambler • BS1 “Bullshooter
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Ramsey Publication No. MLPY2 Price $5.00 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR Logi LOG PERIODIC ANTENNA TABLE OF CONTENTS Introduction .................................4 Antenna Description ...................4 Standard Hook-up ......................5 Low Frequency Modification .......7 Building a Corner Reflector .........7 Building a Reflector Grid .............9 LPY2 Return Loss Plot ...............10 Return Loss vs. VSWR Chart .....10 Warranty ......................
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INTRODUCTION This small log periodic antenna, which we call the ‘Logi’, is ideal for getting the maximum performance out of any UHF to low frequency microwave wireless system. Its directional properties “compresses” the signal into a powerful beam that is 4 times more powerful in the desired direction. It is the ideal antenna for scanners, wireless LANs, and other wireless devices. Its directional properties make it exceptionally well suited for point-to-point links! The units small size
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STANDARD HOOK-UP Normal applications are well suited by the default performance of the unit without the need for cumbersome reflective elements. The standard wiring configuration is simply to use the Logi as the complete antenna and merely add a means of connection for your radio. The easiest method to interface your antenna and radio is through the use of a coaxial cable with a pre-mounted connector. Standard RG-58 and a BNC connector are often used by ‘scanner buffs’ to quickly and easi
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LOGI LOW FREQUENCY MODIFICATION If your radio system requires DC isolation or you plan to use your Logi below 900 MHz, the small connecting traces near the rear of the antenna should be cut. By removing these traces you can extend the effective frequency range down to 825 MHz. You will however wind up with some ‘lumps’ in the Soldered Coax Positioning matching response on the high frequency end. BUILDING A CORNER REFLECTOR Corner reflector antennas have long been used by the Military
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frequency you plan to use. In the case of the Logi, 900 MHz was used to calculate the dimensions. A gain of 10 dB can be obtained with a reflector side length of one wavelength. A two wavelength reflector can be used to achieve upwards of 12 dB gain! It just means you’ll have a bit more wind resistance to factor in. The positioning of the Logi as the active element must also take into account the frequencies you’ll be dealing with. Thankfully, the physical layout of the circuit board t
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1 Ramsey ISM19R or ISM24R (or equivalent) 1 16 1/2” piece of 1/2” PVC pipe 1 1/2” to 1” PVC coupler (non threaded) 1 3/4” to 1” PVC coupler (threaded on the male 3/4” side only) 1 can of PVC cement 3 4” minimum nylon wire ties 10.0" -12.0" 90° Corner Reflector 12.0" Insert the Logi narrow end first. Cut a slot into the PVC boom. Logi front edge placed 1.5" to 3" from vertex. LPY2 • 8
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LPY2 mounted on a Grid Reflector LPY2 mounting Boom for a Grid Reflector LPY2 • 9
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LPY2 RETURN LOSS PLOT RETURN LOSS VERSUS VSWR - CONVERSION CHART Return Loss VSWR Return Loss VSWR Return VSWR (dB) (dB) Loss (dB) 1.0 17.391 11.0 1.785 21.0 1.196 2.0 8.724 12.0 1.671 22.0 1.173 3.0 5.848 13.0 1.577 23.0 1.152 4.0 4.419 14.0 1.499 24.0 1.135 5.0 3.570 15.0 1.433 25.0 1.119 6.0 3.010 16.0 1.377 30.0 1.065 7.0 2.615 17.0 1.329 35.0 1.036 8.0 2.323 18.0 1.288 40.0 1.020 9.0 2.100 19.0 1.253 50.0 1.006 10.0 1.925 20.0 1.222 60.0 1.002 T
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The Ramsey Kit Warranty Please read carefully BEFORE calling or writing in about your kit. Most problems can be solved without contacting the factory. Notice that this is not a "fine print" warranty. We want you to understand your rights and ours too! All Ramsey kits will work if assembled properly. The very fact that your kit includes this new manual is your assurance that a team of knowledgeable people have field-tested several "copies" of this kit straight from the Ramsey Inventory. If
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LPY2 LOG PERIODIC ANTENNA Quick Reference Page Guide Introduction ........................................................4 Antenna Description ...........................................4 Standard Hook-up ..............................................5 Building a Corner Reflector ................................7 Building a Reflector Grid ....................................9 LPY2 Return Loss Plot .......................................10 Warranty ...................................
