background image

DA25 

 1  

BROADBAND 

DISCONE ANTENNA 

KIT 

Ramsey Electronics Model No.           DA25 

Looking for a broadband antenna with a 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 BNC type connector. 

Outperforms 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. 

Summary of Contents for DA25

Page 1: ...waves 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 freque...

Page 2: ...pacitance Meter RAMSEY AMATEUR RADIO KITS DDF1 Doppler Direction Finder HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW7 CW Keyer CPO3 Code Practice Oscillator QRP Power Amplifiers RA...

Page 3: ...e Circuit description 8 Parts list 10 Assembly instructions 11 Installation and Important notes 16 Using your DA25 17 Troubleshooting guide 17 Warranty 19 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR RAMSE...

Page 4: ...early antennas were quite large we ll talk a little more about this later due to the lower frequencies being transmitted Again more recent improvements have allowed us to use higher frequencies with...

Page 5: ...is regular we say that the wave has a frequency of repetition This frequency in fact is the reciprocal of the time it takes for the wave to complete one full cycle mathematically speaking f 1 T By the...

Page 6: ...e old days of radio The common use of low frequencies meant much longer wavelengths and significantly larger antennas for reception Today s modern electronic devices tend to operate at much higher fre...

Page 7: ...e frequency or the length of wire to match a given frequency Antenna Gain Another performance specification common with antennas is their gain usually given in dBi units To understand this concept let...

Page 8: ...he line and precipitate a high VSWR Typical usable VSWR ratios are in the 3 0 1 0 range for commercial available communications equipment while the robust discone design actually outperforms these at...

Page 9: ...transmit antenna as well Experimenters have used this particular design for a host of transmit applications including increasing the distance of their PC s wireless LAN to boosting the range of cordle...

Page 10: ...sical relationship to each other so there s minimal chance of inserting wires into wrong holes Second whenever possible we install in an order that fits our Learn As You Build Kit building philosophy...

Page 11: ...eived parts against the parts list The parts list describes the vari ous markings that may be found on the kit parts Carefully sort the parts into small piles an empty egg tray does nicely for this pu...

Page 12: ...illed with tinned copper We will use this circuit board to transition form the coaxial cable assembly to the antenna 3 Insert the full length tinned center conductor wire through the P1 hole in the ce...

Page 13: ...n Fasten the screws into place using the 6 32 stand offs pro vided Be careful not to over tighten the nylon parts or they may shear off Now we are getting to probably the most difficult solder connect...

Page 14: ...the ground connection completely This may take a little while depending on the wattage of your soldering pencil Whew Well we are over the worst of it now just a few more steps to complete assembly of...

Page 15: ...ruding from the disk Have a look at the above diagram to help out if necessary CONGRATULATIONS Your discone antenna is now complete Have a final look over your work paying particular attention to the...

Page 16: ...it the coupler firmly into place after threading the cable assembly through it If the glue sets up with the coupling in a little tilted you will forever see a slightly off balance discone IMPORTANT NO...

Page 17: ...h wire Make sure that the wire hasn t folded under the disk and shorted by touching the ground connections somewhere all solder connections Still having trouble While we had hoped that it wouldn t com...

Page 18: ...we value your opinions comments and additions that you would like to see in future publications Please submit comments or ideas to Ramsey Electronics Inc Attn Hobby Kit Department 590 Fishers Station...

Page 19: ...be assured that the 1K ohm resistors are actually the missing 10 K parts Hum m m I guess the red band really does look orange Ramsey Electronics project kits are packed with pride in the USA If you b...

Page 20: ...RTS05 Small Diagonal Cutters Ramsey RTS04 Technician Tool Set Ramsey TK405 ADDITIONAL SUGGESTED ITEMS Optivisor Magnifier Headband Ramsey OPMAG Holder for PC Board Parts Ramsey RTS13 Desoldering Brai...

Reviews: