Blank Log & Information (PDF-86kb)
(Used to Log Your Own "Satellite" /K0S Station)
StrangeAntennaChallenge_BLANK_LOG.xls (.XLS Excel Spreadsheet-103kb)
(Blank K0S Log & Information in Spreadsheet Format)
Entry Forms (PDF-58kb)
(To Report Your "Satellite" /K0S Station Information to Us)
Icom's new band plan chart (PDF-1.5Mb)
(I Always Like Having An Icom Band Plan Chart At Hand)
k0s_field_manual.pdf (PDF-5.8Mb)
(I Wrote This Free PDF to Help Explain the Behavior of Both Normal & Strange Antennas -- People Seem to Enjoy It)
newbie_antenna_woes.pdf (PDF-433kb)
(The Newest of My Amateur Radio Writings -- About 1/2 Completed)
Erik Weaver nØew
4857 E. Farm Road 136
Springfield, MO, 65809
* This includes all satellite stations as well as the official K0S special event station.
To clarify somewhat by example, if one of us were to bring a large tent, we could fly the entire tent as an antenna, but we could not just pull out its longest metal poles and use them as antenna elements. If there is a basket ball hoop on-site, we can use that, but we couldn't just bring the main supporting pipe and use that as a vertical element. You have to use your common sense. We cannot identify every possibility out there... just don't use plain ol' wire or pipe. Otherwise we'd just be able to go buy long lengths of copper pipe and use them as an antenna (which would work great, of course). But what would be the fun in that? That is a normal antenna, not a strange antenna!
Please remember that mobile stations are not in and of themselves "strange" nor are maritime mobile stations. Now if you are using the transport itself....
If you look through the previous years events you find a variety of strange antennas, including my painting easel dipole. I worked Alaska through Mexico with this antenna at 100 watts. The tape measure dipole easily worked Europe, also at 100 watts, and most notably Kygyzstan, which is along China's western border. These "antennas" offer just a taste of the possibilities.
...If you can tune it...
...If you can load enough power into it...
We'll look for you on the air. We really hope you try your own "strange antenna" because it really is a whole lot of fun! If you are organizing a larger club function around this idea it provides a great opportunity to increase interest in your club. Let the media know what you're doing (preferably a few days in advance). If it is a slow news day in your area of coverage you stand a better than average chance of getting some media attention.
Observe FCC regs: Your-Call "Slash" KØS (e.g.: Callsign / KØS)
Having double-checked our connections, we then reduce power and transmit in RTTY mode while slowly rotating the roller inducting so as to slowly add more inductance to the tuning solution. Watching for a "dip" in the reflected power needle (we are seeking a minimal value of reflected power with a maximum value of forward power) once we see the reflected power drop, we then ever-so-slowly adjust the capacitor's to further produce a reduction in reflected power, while causing an increase in forward power (up to a maximum value equal, or nearly equal to, the current user-selected transmitted power of the XCVR).
Slowly is the operative word here! If you madly swing the knobs hither and yon you very likely will never see the dip!
Once we achieve the best result we can find (defined as minimal reflected power and maximum forward power) we increase the transmitted power, and repeat the above steps. Once that results in the "best tune" we repeat again. Increase power, adjust the coil, adjust the two capacitors. Repeat as needed.
Generally, we start with very low power. Perhaps 5-watts to 10-watts when using a 100-watts XCVR. The second step may have the transmitted power increased to 20- to 25-watts. The third step will bring us up to the order of 40- or 50-watts, and the net step will bring us to approximately 75-watts. From 75-watts, if the tuning process has been smooth and fairly easy, I'll go to 100-watts (my maximum power) but if the tuning has been difficult, or is very sensitive to small changes, I'll increase power to the maximum in smaller increments. Once you have matched the impedance ("tuned" the antenna system) transmit an inquiry: "Is this frequency in use?" a couple times. If you still hear nothing, go ahead and start calling CQ.
If you observe this "tuning up" process while seeking an impedance match between the antenna system and the XCVR, you will note that you are seeking two simultaneous results: (1) lowest reflected power; and (2) maximum forward power. By observing the dual-needle display it is obvious that a low swr is generated anytime the reflected power is very low. I generally find the reflected power is first reduced, and then the capacitors are tweaked to produce the maximum forward (transmitted) power while retaining minimal reflected power. This is to say, during the above tuning process I am most concerned with maintaining a low-level of reflected power, and not overly concerned about the forward, until I reach the final tune. However, if you are not able to incrementally increase the forward power throughout the tuning process there is a good chance something is wrong or in need of adjustment.
For those of us using a 100-watt transmitter, any swr value of 1.5:1 or less is quite good. Further, there is so little power difference between 1.5 and 1.3 or even 1.0:1 swr there is very little reason to seek a "perfect" swr. Also consider that our amateur radio equipment is not lab-quality. For example, when we read a 1.3:1 swr, we have no way of knowing whether that is really a 1.5:1 or perhaps a 1.1:1 swr. Nor does it really matter. Most late-model XCVRs have a self-protection circuit to protect the finals from excessive heat. When I find a difference between my MFJ swr meter and that on my Icom XCVR, I trust the Icom's meter.
When I transmit I want to see the XCVRs power output reaching the maximum (for which I have set it), the swr to be acceptable (anything 1.5 or lower), and the ALC to remain near the top end of it's reading, without exceeding it's maximum suggested limits. (Check your manual for your XCVRs recommended settings.) If the ALC isn't fluctuating in the upper 1/5 of the recommended range I adjust the mic gain until it does.
Given a sheet of paper and pen to log, now we're ready to play radio!
( Usually one of us is working the mic, with pen and paper at hand, while the other enters the log information in the laptop. )
One of the nicest features was the ability to sweep a user-defined range of frequencies at the touch of a button. Sweetness itself I assure you! A comma separated file is also generated at the same time, so once saved under a unique filename, we are able to refer back to this sweep at a future date. Very nice!
The only trouble we experienced was getting the device to recognize which com port was needed. That was very clunky and was the most time consuming part of using this device. Still, a great time-saver compared to using the MFJ-269 as we had in the past. And as already mentioned, about 3-times as accurate.
