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Diy PA0RDT Mini Whip Active Antenna 10KHz to 30 MHz
>> YOUR LINK HERE: ___ http://youtube.com/watch?v=af1VRHDSZCg
For good reception of weak SW , MW , and LW signals except good receiver, also is need a good antenna . I have often read about the famous Mini Whip antenna from PA0RDT, but I was quite happy with my existing antenna, which is actually a 20m wire stretched out in the roof of my house. However, I decided to make such an antenna and compare it with the existing one. • The Mini-Whip antenna is a type of vertical antenna that is powered on top, where the voltage is very high and the current is very small.The impedance is very high and is perfectly tuned to the input level of the amplifier in the active antenna performed with the JFET F310, which has a very high impedance. The vertical antenna is formed by the vertical part of the coaxial cable that powers the antenna. The second transistor is an amplifier with a high standby current (approx. 45 mA) ensuring a large dynamic range of the amplifier. • I chose to make a Mini Whip antenna that has slight modifications to the original, and was made by my compatriot Mile Kokotov,Z33T. • The antenna is made of universal proto board and is very compact.The change to the original design was made in the power supply unit, where was added a RF transformer as a galvanic isolator.This results in much better reception especially at lower frequencies. In this particular case, instead of the 2N5109 transistor, which is recommended in the original design, I made this active antenna with a BF259 transistor that has similar characteristics.It is very important that the outer conductor (grid) of the coaxial cable is grounded at the base of the antenna and once again ground to the point just before the coaxial cable enters the house. With this earthing done, the obstacles are eliminated! • The antenna is embedded in a piece of water pipe that is closed with lids on both sides, thus protecting it from atmospheric influences. As you can see from the video, it is set on a balcony 3m above the ground. • Lastly, the most important part. I tested both antennas on the same receiver, at different frequencies.The results were amazing. This small active antenna, though located only 3m from the ground, gives an incomparably better reception than my wired roof antenna, all over the range from 50Khz up to 30Mhz. Particularly good results give on the lower frequencies, MW, LW and VLF ,where the wired antenna is almost useless. At the beginning of the video you can see short inserts showing the difference in reception between these two antennas at 49m and 22m band. • This is an excellent active antenna for reception at very low frequencies up to 30 MHz. In one of my next videos I will also show you practically, on several of my SDR receivers how superior this antenna is on all HF bands. • If you are interested in this area, look at the Playlist with all my DIY Radios at: • • All My DIY Radio Receivers • Visit my Youtube Channel for more Projects , DIY and How To Make videos: • / mirkopavleskimk • by mircemk • SUBSCRIBE LIKE AND SHARE !!!! • Thanks for your Support !
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