endobj this The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. Technical specification : Type : 49:1 Unun Frequency : 1.81 MHz - 30MHz Impedance ratio: 1:49 Input Impedance: 50 Output Impedance: 2500 Power Handling (CW/SSB) : 250W Core Type : 1x FT240-43 by Fair-rite Co. Capacitor 100pF 3KV Assembled and tested. The free end of the untwisted portion of the long wire (past the 14th winding) will be secured to this bolt as well on the inside of the box, while the radiator will be secured to it on the outside. 35. The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. As typically A couple hours later when I sat down to do some more DXing, I made contact with a gentleman in Slovenia-my second European contact. % First, it is important to understand the difference between the end fed half wave and a random wire (or "long wire") antenna: the random wire is just a piece of wire that is matched to 50 Ohm impedance using an antenna coupler, sometimes adding a 9:1 unun. Enclosure Height: 5.000 in. the C code, in Matlab or Octave get a plot by simply putting the 4 0 obj The 49:1 impedance transformer will help you bring down the high impedance of your resonant EFHW antenna to almost 50 Ohm. The "Super Bullet" End Fed Long Wire Antenna Matcher - 1500/3000 watt rated for Super-Punch of your signal! Here Is a 250 Watt Home-Brew That I Made In about an Hour. The 9:1 may work best with that length wire and a tuner, but some say that length is undesirable for the hf HAM bands. SO-239 (UHF female) chassis mount with screws, nuts, lock washers. Winding 1:64 Matching Auto Transformer on the FT240-43 core. Just add or subtract as needed a little at a time toget the best compromise. 80m up, W3EDP's 84' antenna, 17' counterpoise is probably the way to go. I got three FT240-43 toroids (two would be lighter, but three increases the curie point so it can handle longer duty cycles), a spool of the 14 gauge enameled wire . While I have not done so yet, I plan on gluing the test cap to the back of the junction box. I have included a screenshot showing the stations that reported spotting my 200 mw beacon over the last 16 hours. Use a slide rule! The kit includes the parts needed to construct a 49:1 impedance matching network, which will transform the impedance to 50 Ohms, which will suit most transceivers. Post Reviews Its really an impedance transformer (9:1) to feed a high impedance, end fed (unbalanced) random wire which is likely to be a few hundred ohms, and transform it into something closer to a 50 (unbalanced) coaxial input, hence UnUn. 7 0 obj 35. Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. SO-239 connectors are silver plated with Teflon insulation. >> Electronics unavailable, a random wire can save the day, but it is important to are easily converted to half wavelengths by the famous 468/f generally is that for a given ham band there are min and max frequencies which The length should be calculated based on the lowest frequency to be worked. 9:1 UnUn End Fed Long Wire Lengths - Pretty Simple. A png image named g.png will be created. Performance is ASTOUNDING, far exceeding my expectations. HF & Shortwave The key to end fed antenna success is the matching network interface between the long wire antenna and the coax feed line and feed line choke at the transceiver. An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). var sc_security="1df091cc". The First Thing New Hams Often Ask:What Is An UnUn? Proudly powered by WordPress 1863 1.49 swr 3915 2.50 7200 1.80 14.332 1.29 18.130 1.07 21.300 1.40 24.950 1.30 28.400 1.37 This is a great antenna that is . Here Is a 250 Watt Home-Brew That I Made In about an Hour. endobj So, if you connect a length of wire that presents an impedance of about 450 to the input, you'll get an impedance of about 50 on the output. The major point of this message is to tell you that approximately 20 minutes after I connected the balun unit to the antenna, I made contact with a gentleman in Italy-my first European contact!! &nb >> STORE Make sure the beginning few inches of twisted wire is not involved in the winding (i.e., just hanging down from the toroid). So for 80 meters (say 3.525 MHz) this gives you about 133' of wire. Just add or subtract as needed a little at a time to get the best compromise. (The numbers aboveare a great start, thanks to Jack and Mike! It uses an FT140-43 or FT240-43 toroid in a 49:1 impedance matching unit at the base and a 110 micro Henry (H) coil to act as a loading coil for 80m and a choke to stop higher frequencies using the last 2m of wire. <> Hopefully these random wire length calculations will help us all make this "easy" antenna work better! The following wire connections do not need to be made in the order I described. A 9:1 matches 50 ohms to 450 ohms and that turns out to be an ok compromise for feeding 50-100ft of wire for general purpose SW receive. (Center fed is so appealing because you avoid this.). presents an extremely high impedance to the tu This design is excellent for matching both long and short length wire antennas for multiband use. Caution: When used atfull power rating of 1kW, the antenna must have a low SWRon the band selected and be used on a 50% duty cycle. Vhf and Up >> bands you're intested in in a vector like the example below, by typing. The graph below shows lengths to avoid for different collections of bands. Kj8~q7c? For example, In other Privacy Policy understand its properties. 9:1 or 49:1 unun for end-fed long/random wire?