![]() ![]() But, if the boom length gets too long and so on, then I have to go with the yagi with the less elements. For myself, if adding a director can be accomplished with the materials that I have available, and if I use one of the computer modeling programs to confirm the design (like Yagimax that is available from this site), then I definitely will go with the additional director. In a few cases adding a director that is not properly positioned can actually reduce the gain of the antenna. A DB = 100 dB and 'db' is not a notation of relative signal strength.Īs for adding a director to any particular antenna you have to basically redesign the antenna to get the best performance. Remember that the correct notation for a decibel is dB and not DB or db. But, during a contest or working some 'rare' DX, the extra 1 to 2 dB gain can definitely make a difference as to how long you 'sit in the pile' calling the station. On HF for general 'rag chewing' probably not. On FM, probably nothing that is going to make any real difference. The pattern will always be the same.On weak signal VHF (CW or SSB) it could definitely make a difference. (that also goes by the way for not calculating hairpin matches within the design etc)Īnyway if all elements are isolated there is no influence.and you dont need to bare in mind the boom thingy. Which will cause a change in the antenna pattern. Since steel and aluminium dont combine the electrical connection become less when corrosion (time) steps in. On 11 meter its not a real big issue but on higher bands it is. If you carefully calculate antennas you need to calculate it with boom. That uses steel U bolts to be attached to the aluminium boom. Most manufacturers use steel U bolts to secure the element to the aluminium element plate. I actually prefer isolating everything.(each element) What i will need to know from you.is the distance between the two elements. (thats another advantage.this antenna can truly be "dc-grounded".)Īt the end of both elements you need to connect both to each other. You can leave the other part of the radiating element "dc-grounded" to the boom. ![]() Isolate that "original" radiating element. ![]() Place 1 element below the radiating element.Ĭut the "original" radiating element in the middel. Not only the azimuth point is remarkable.but also the elevation plot. Some migth recognize when the rain comes up the noise floor runs up. High impedance yagi's (like the F-yagi) are less critical. It is also known that low impedance yagi's are critical to rain/snow/buildings. Thats a lot higher than a couple Kw's hihi. Which they sometimes claim for the quad aswell.Īnd power is limited to the element diameter instead of the matching device. Since it is a loop configuration, some say it has less noise due to that fact. However a RFchoke 4/5 turns RG213 10cm diamter or a 1:1 balun is adviced. So there is no loss there (how small that migth be) No gamma-match or other matching device is needed. The higher gain and FB numbers are already reached with slightly less boomlength compared to the Maco/Sig. I use a short boom Yagi and had many xlnt results - BTW. Longer is better nothing wrong with a short boom if that is what you have. This page will give dimensions for either a long boom or a short boom element spacing. Another reason for four elements is the fact that in mounting the antenna, the mast will not be near the driven element or the matching network. The dimensions are all in metric, but you can get a calculator online to change them to US measurement standards. A four element yagi sporting 6 dB gain over a dipole will produce a beam width on the order of 80°, that’s less that a quadrant of the compass. Probably a bit better than the dimensions than the Maco's use - BTW. You might want to consider using the element spacings from the Henry HPSD page. After I mounted it, I re-checked it and it was solid. That was usable and verified info, and it really was easier to tune using that method. I adjusted my beam that way after I was told to do it that way. Tune the Gamma match with the beam on the ground laying on its reflector and pointing straight up into the air. Maco's tend to be a bit sloppy in that fit. Just make sure the elements are snug on their mounting hubs and the elements and are as parallel as possible. ![]() Better to have a longer beam than the shortened one that page offers/shows. The Maco has a longer beam length than the optimized Yagi you saw on that page. ![]()
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