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AMPLIFIED
BROADBAND
DISCONE ANTENNA
Ramsey Electronics Model No.
Looking for a broadband antenna with full 360 degree
coverage? Discover what communication professionals have
known for years using a "discone" antenna. Use this antenna to
bring a multitude of signals out of the noise making it ideal for
scanners and Ultra High through Microwave Frequency
receivers! Search the airwaves for signals with this unique kit!
•
Omni directional performance; no need to point in any direction!
•
Learn about antenna theory, and what makes the discone an ideal
broadband antenna!
•
Covers all frequencies between 450 MHz and 2500 MHz, and you'll
learn why!
•
E-Z cable connection, industry standard "F" type connector.
•
Out-performs models costing tens to hundreds of dollars more.
•
Super small in size for easy mounting almost anywhere! An ideal
"apartment" size antenna!
•
All hardware and pre-drilled metal work included.
•
"Forgiving" design gives you a high performance antenna each and
every time.
DAP25 • 1
DAP25
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Summary of Contents for Ramsey Electronics DAP25
- Page 1 AMPLIFIED BROADBAND DISCONE ANTENNA Ramsey Electronics Model No. DAP25 Looking for a broadband antenna with full 360 degree coverage? Discover what communication professionals have known for years using a “discone” antenna. Use this antenna to bring a multitude of signals out of the noise making it ideal for...
- Page 2 RAMSEY MINI-KITS Many other kits are available for hobby, school, Scouts and just plain FUN. New kits are always under development. Write or call for our free Ramsey catalog. DAP25 KIT INSTRUCTION MANUAL Ramsey Electronics publication No. MDAP25 Rev 1.4 First printing: November 2001 COPYRIGHT 2001 by Ramsey Electronics, Inc.
- Page 3 Introduction ......... 4 Circuit description ....... 8 Parts list ........9 Schematic and Parts diagram ..10 Assembly instructions ....11 Using your DAP25 ...... 17 Troubleshooting guide ....17 Warranty ........19 RAMSEY ELECTRONICS, INC. 590 Fishers Station Drive...
- Page 4 Enter the Ramsey line of discone antennas, allowing us to “tinker” with the airwaves at an affordable price.
- Page 5 (“λ”) reducing our equation to λ = v x T. In English, the wavelength is equal to the velocity multiplied by the period of the waveform. Pretty neat, huh! Electromagnetic Wave One Wavelength One Cycle Some Amount of Time DAP25 • 5...
- Page 6 Looking at the desired waveform, the shortest length of wire that will resonate at a given frequency is one which is just long enough to permit an electric charge to travel from one end to the other and then back again in the time of DAP25 • 6...
- Page 7 Although we are using our discone as a receiving antenna, the rules of antenna gain are reciprocal so we can count on at least a 14 dBi improvement in the signal power over the entire frequency range. DAP25 • 7...
- Page 8 The discone dimensions have been calculated such that the usable performance range is between 450 MHz to 2500 MHz with a typical VSWR of “2.0 : 1.0” or less. The amplified discone antenna takes advantage of a low noise MMIC amplifier DAP25 • 8...
- Page 9 The DAP25 kit which your are about to assemble is the preamplified version. The advantages to this particular model are that in addition to the gain and performance of a standard discone antenna, the DAP25 offers an additional low noise amplifier to provide higher gain for reception of weak signals.
- Page 10 DAP25 PREAMPLIFIER SCHEMATIC DIAGRAM DAP25 PREAMPLIFIER PARTS PLACEMENT DIAGRAM DAP25 • 10...
- Page 11 The procedure is to take a small amount of glue (usually with a pin or toothpick) and “dab” the circuit board in the place where the component will be affixed. Be careful not to apply too DAP25 • 11...
- Page 12 RAMSEY "Learn-As-You-Build” KIT ASSEMBLY There are solder connections on the DAP25 printed circuit board. Therefore, PLEASE take us seriously when we say that good soldering is essential to the proper operation of your discone antenna kit! •...
- Page 13 1. Noting the surface mount installation instructions, install resistors R1- R3 the 220 ohm resistors (marked 221). These resistors are connected in parallel, so it will appear that they are “bridged” together (R4 is not used). DAP25 • 13...
- Page 14 Have a look at the diagram to see what the complete “pre-assembled” cable should look like. 1 inch Braid Coaxial Cable Center Conductor 1/2 inch Center Insulation DAP25 • 14...
- Page 15 Bottom (Copper Plated) side Now we are getting to what is proba- bly the most difficult solder connec- Coaxial Cable tion of the entire antenna kit! We will solder the circuit board assembly to the funnel cone. DAP25 • 15...
- Page 16 Trim off any excess lead that is pro- truding from the disk sec- tion. Have a look at the dia- gram to help out if neces- sary. DAP25 • 16...
- Page 17 Note your signal strength indication of the station, and proceed to disconnect your existing antenna and replace it with your DAP25. Power up your DAP25 by connecting the other end of the “F” type feed cable to the power inserted end labeled “TO AMPLIFIER”.
- Page 18 TROUBLESHOOTING GUIDE If your DAP25 is powered up but does not work at all, re-check the following: • Is that disk on the top soldered to the feed through wire? • Are there any questionable solder joints that may be shorted? •...
- Page 19 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.
- Page 20 Quick Reference Page Guide Introduction ........4 Circuit description ......8 Parts list ........... 9 Schematic and Parts diagram ..10 Assembly instructions ....... 11 Using your DAP25 ......17 Troubleshooting guide ...... 17 Warranty .......... 19 REQUIRED TOOLS • Soldering Iron Ramsey WLC-100 •...