Taktenna Antenna Project - N6. PETThe Build: I built an experimental antenna similar to the TAK- tenna spiral antenna and was evaluated for SWR response over the frequency range of 7. MHz, or the 4. 0- meter band. TAK- tenna markets and sells a 4. The advantage of this configuration lies mainly in its compact size. The finished antenna easily fits into a 3- foot cube. My friend John W9. APX, was kind enough to provide me the manual and some dimensions of his TAk- tenna for my evaluation and comparison study. For this experiment the TAK’s major drawback was its fixed length beam and narrow bandwidth. An easy to construct design that overcame this shortcoming was needed. Materials used to construct an adjustable length beam antenna are available at any home center and consist mainly of PVC electrical conduit, and two sizes of PVC water pipe. Gauge #8 solid copper wire was chosen for the antenna because of its quality and goal of attaining a wider bandwidth. The Theory: Primary spiral antenna design parametersthe desired resonant center frequencythe length and gauge of wirethe pitch per turn and starting point of spiralthe length of the hook up wire that connect the antenna to the coaxthe minimum distance the antenna wire is allowed to come to the end of any one PVC support arms. Once these parameters have been determined, many spiral designs are possible by varying the spiral pitch, or distance between turns, and the starting distance from the hub of the spiral. From a mechanical perspective the most important design consideration is how close the outermost end of the antenna wire comes to its supporting spoke. An antenna wire that is an inch too short will leave a large section of antenna wire unsupported, whereas one that is an inch or two longer than needed to reach the last support is easily tolerated, and may even be an advantage in subsequent tuning. Therefore, it is important to choose pitch and start values with this in mind. Calculating the effects of starting distance and pitch on a known length of wire can be tedious, and finding the combination that satisfies the condition that the wire reach the last spoke with little or no overhang can be daunting. A graphic showing the spiral antenna’s most important parameters which are: start point, pitch, safe edge, spoke length, and arm length. Computing for the wire length follows this basic formula in deriving the half wave length: Center resonant frequency will be designed for 7. MHz and with this formula we get 6. Therefore; quarter wavelength is 3. A table of inputs and outputs follows the diagram. The American Radio Relay League (ARRL) is the national association for amateur radio, connecting hams around the U.S. Amateur Radio, Homebrew. DatasheetCatalog.com is free an online datasheet source for electronic components and semiconductors from several. Ham Radio Software links for all modes and communications. Software for the Amateur (Ham) radio operator. Building Your Own Gear is Half the Fun! The Elecraft K3S (Factory assembled or kit), KX1, K1, K2 and K2/100 amateur. October 1997’s Novice Notes looked at compact antennas that amateurs use to operate from confined locations. The smallest antenna described for 80 metres was a. 100 useful links about Radio Tools and Utilities for amateur radio operators collected in Software/Utilities at The DXZone. We are proud to be your choice for high quality, affordable amateur radio supplies to the international ham community. We are proud to give back to the community by. Inputs are in peach, outputs are in yellow colored cells. The designer enters the desired frequency, the length of hookup wire, assumed velocity factor, and safe edge. In response, the spreadsheet calculates the required length of antenna wire in both inches as well as feet and inches. The spreadsheet does its calculations in inches, but the user will find the conversion to feet and inches more practical when cutting wire to length. Of the remaining two boxes, one is labeled pitch, or the distance between turns, and the other is labeled start, or the distance from the hub to the point on spoke R1 where the antenna will start. Adjacent to these two inputs are two outputs labeled turns and min spoke. The significance of turns is that values ending in 0, . A value not ending in one of the above fractions means that the antenna wire will end between spokes. As mentioned above, a little over is much more desirable than a little under. Minimum spoke determines the overall size of the antenna. In fact the diameter of the antenna will be twice this value. The length of the cross arms will be twice the sum of the min spoke plus the safe edge. First Build v. 1. This a ongoing project with picture slides of my progress I have on building my version of TAK- tenna/Spiral dipole. Later, I will update this page with more details of my build, mods, dimensions, and most importantly, the antennas performance. Design and Construction Of An Adjustable Beam Spiral Antenna. Drill Jig. Construction consisted mainly in cutting PVC to length and drilling holes. A modified spade bit, ground to the diameter of the gray PVC conduit used for the cross arms, was used to drill holes in the movable sections of the beam. To insure that the holes were at right angles to each other, a simple jig was used to hold the beam member during the drilling operation. The image shows the jig in use during the drilling operation. After the first pair of through- holes are drilled, a piece of scrap PVC is inserted through these holes, and the piece is then returned to the jig with the scrap PVC now resting on the locating rails. This insures that the next pair of holes in the PVC will be at right angles to the first pair. In the above photo, the smaller diameter PVC has been drilled and the spiral arms inserted. The two cross members are secured with a single self- tapping screw. The two cross members are secured with a single self- tapping screw and sealed with cap. In contrast with the TAK, the beam in this design is not one but three pieces. Two hold the spiral supporting arms, while the third, larger in diameter section, fits in the other two. This arrangement produces an adjustable beam. The above image shows how one section slides over the other, in trombone fashion, allowing for the beam length to be varied.(1) THE ASSEMBLY(2) THE INSTALLATION(3) Observation: The antenna’s SWR and resonant frequency was hugely affected when it was elevated from 8 ft. Test location was about 1. I had to re- adjust the boom length and the tap points to retune it back to 7. Mhz. Antenna characteristics has changed drastically when elevated and had to be compensated by re- tuning. I also observed that having my hands come near the antenna analyzer affected the results. The SWR will drop from 3. I touch the analyzer (antenna analyzer should have been grounded). This shows that there is RF radiating from the feed line, which I am also radiating/reflecting . I had no choice but to continue tuning with this circumstances. Second test was done in the shack. The SWR across the band went up above 3. Although it was tunable with my external LDG 6. Pro II ATU, the SWR was too high that my in- board tuner could not even tune the antenna. A 1. 3: 1 SWR was attained on 7. LDG ATU. It is imperative that the antenna is in absolute resonant to the designed frequency. TX report from 3 stations in Arizona, Texas, and Nevada had similar reports. They were saying that the Taktenna was half an S meter below my 5. Again this is inconclusive since the antenna has a high reflected power and I was not sure if the Taktenna is properly pointing to their direction. NOTE: It is unfair to compare the performance of TAK- tenna to Ultimax’s 5. The endfed is used as a baseline on how much compromise the Taktenna has for being compact and uni- directional (portable+ directional vs. My noise level was about 2 S- meter above my Endfed antenna. The noise was almost overwhelming the signal that I had to switch to the Endfed on receiving and switch back to the Taktenna for transmitting. The antenna tuned successfully from 6- 8. SWR below 1. 5. Interesting observation was the antenna performed well on 6m. In comparison to my vertical Cushcraft AR- 6 Ringo and the 5. Using 2 of N6. LXX 6m repeaters as beacons (5. Mhz Mt. Harvard & 5. Mhz Santa Clarita) , I gained almost 3 S- units once I was able to beam the Taktenna toward the correct bearing of the repeaters. Build v. 1. 2. After a few rigorous trial and error in finding the sweet spot for the antennas resonant, I will be refining the first build with a more exact dimension of all its components. During testing, I had to cut and add the lengths of practically every part of the antenna to experiment and note the results. Now that I have the exact “real world” dimensions for the center desired frequency, I was able to interpolate the velocity factor of the design from its original theoretical values. This will be very helpful if I need to design for a different band. I also realized that the 2. Here is the next version of this build I will be applying to the v. Final wire length is best at 3. The distance from the center of the boom to the point of the arm (ARM0. DONEInstall 1: 1 5. BALUN at feed line – DONEHookup wire length is also critical. Measured SWR below 2: 1 within the whole 4. SWR. This was the first objective of this modification and build. TAK- tenna vs. Increasing the distance. Beam length can be used. The combined length of antenna and hookup wire has a significant. The longer the combination, the lower the. The diameter of a spiral antenna affects its bandwidth, as measured by the frequency. SWR is equal to or less than a value of 2. Increasing spiral diameter or wire pitch increases bandwidth. TAK- tenna Manual. Download – TAK- tenna Manual. TAK- Tenna- 4. 0Design Upgrades. These mods are in reference to the original TAK- tenna design. From various reviews, I have read that the number one complain was its very narrow bandwidth, tuning limitations attaining SWR below 1. Other mods I’ve added are symmetry, durability and stability improvements in the design.(1) Telescopic Boom. This is a considerable small size boom for a HF antenna. Although it is not technically a boom separating parasitic elements, by constructions it is used as one. Having the option to adjust the distance between both elements will surely give the antenna more flexibility for tuning its SWR and intended resonant frequency. Center boom was a 1. I corrected this by having the wire run between the center of each spreader arms.(3) Increased Spiral Pitch / Starting turn at 5. This was addressed by starting the turn no closer than 5. This also increased the spreader arms to 3. Original design uses AWG#1. This help resolve a wider bandwidth and better wire wrap with a firmer solid wire.(5) Installed 5. KW rated BALUNThis addressed the problem of RF radiating at feed line.(6) Used and Re- purposed U- Bolts. Home. Brewed – 4.
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