Not Reporting Contest Operating Time

Right up front I'll say that most readers won't find this article of the slightest interest. I've been busy with travel, tower work and family responsibilities and I've hardly even operated recently. After a brief and casual effort in SAC (Scandinavia Activity Contest) CW last weekend and reporting my results to 3830, this topic came to mind as I perused score submissions alongside my own. So why not a brief article on one my observations.

The subject of reporting raw scores during and immediately after contests has long been tainted with controversy, although most contesters pay little to no attention. They don't care, and that's fair. For the most part neither do I. I report my results promptly after contests, and typically submit my log to the sponsor at the same time. 

Opportunities for competitive comparisons have gone further. While I have only participated once while using and monitoring the contest online scoreboard, its popularity is growing. Participation is optional and you can control how much detail is shared. Soon we may have real time scoring. These developments are changing radiosport in many ways and have the potential to make it better and more interesting.

Where's the controversy to which I alluded? Certainly there are some that object to increasing dependence on the internet during the contest, or consider their operating tactics private. However the specific topic of this article has nothing to do with the internet or real time tactics. Rather, it's about disclosure, and how that information can be used by other contest participants. 

It comes down to: how much about your performance and objectives should be available to others? Should early (even real time) disclosure be an option or mandatory, and how can it help or hurt you in the current and future contests? There are major contests like CQ WW where your submitted log becomes public after the final results are published. So if you enter you must agree to this. Others can analyze your log for insights, but only long after the contest is over

Disclosure and public logs are not the norm for the majority of contests. Many choose not to disclose anything. As mentioned, real time contesting will greatly increase disclosure, and that can help or hurt your competitiveness. Do you want others to know that you are doing poorly on 80 meters, that you can't maintain a high rate during big openings, when you take off times, or what category you've entered?

I have no answers. All I can say is that more disclosure is the trend. Get ready for it since, if you contest, you will be affected. If not today then soon.

That's a long preamble for a short article. So let's get to the one aspect of disclosure I want to talk about today: hours of operating time in a contest. At a glance it discloses your rate by simply dividing QSOs by hours. Or does it?

An important measure of your performance in a contest is rate. At it simplest it is the ratio of QSOs to time, typically average contacts per hour. Higher is better if you are competitive. But too great a focus on rate can hurt if you spend less time hunting for multipliers. It's just one metric in a complex calculation of performance.

It can be very illuminating to compare your rate to others with similar or better stations in your area. If you're that station, your on time disclosure helps them to assess their relative performance. The comparison can help you, and other participants, to address shortcomings in future contests, if that's your objective.

This is a screenshot from 3830 a few hours after SAC CW ended Sunday morning. Most operators reported their operating time. I did not. Am I avoiding disclosure of my performance from other participants to give myself an edge? After all, I now know something about their contest performance that they do not know about mine.

The answer is: no. Lack of disclosure can have non-nefarious reasons. My reasons for not reporting operating time in this particular contest are as follows:

• I don't know
• I don't care
• It doesn't matter

This is typical when I operate casually in non-major contests.

Why don't I know? On time is calculated by pretty well every contest logging application. I use N1MM+ and it is easily selected from a drop down menu. The answer to the question is that I didn't look. Which brings me to the next two points in the list.

I didn't look because I didn't care. That requires an explanation. Even during a casual contest operation it is useful to look at the rate and to select operating hours when propagation and activity is best. I do that in some casual contests but not all. When I do I usually report my on time, since I monitor it and use it to measure my performance. It can provide useful feedback during casual and part time efforts even though a full time effort will typically result in a lower rate since, eventually, you run out of stations to work or you need to move to bands where contacts are more difficult.

The issue is that on time has a common meaning in addition to the definition specified in the contest rules. For example, if I operate for 15 minutes, step out of the shack for 20 minutes and then operate another 40 minutes, by the common meaning I operated for 55 minutes. In almost every contest there is a minimum off time period, typically 30 or 60 minutes. Therefore, per the rules, my on time was 75 minutes; the 20 minute break counts as on time. N1MM+ and other contest loggers use the definition in the contest rules.

That's how I operated SAC: operating for a bit, wandering out of the shack to do other things, then do a bit more operating. I did this without paying attention to on and off times. Therefore the software would calculate a time that does not represent my chosen pattern of activity. That time calculation is not personally useful to determine rate or anything else of consequence. 

The contest sponsor will calculate an on time from the submitted log in accordance with the rules. That calculation should match the time calculated by the software. Therefore it, too, is of no use to me. I ignore both.

Even if I had been competitive the on time calculation does not impact ranking in the contest results. In a contest like SAC where you can operate for the full 24 hour period, your choice to operate less is irrelevant. Rate doesn't enter into the ranking determination; only your score matters. That is why my third reason is that it doesn't matter.

In contests like NAQP and CQ WPX where single ops are limited to 10 out of 12 hours and 36 out of 48 hours, respectively, on time does matter. I pay close attention in those contests, seeking to maximize on time without exceeding the limit. Indeed, selection of off time is determined by contest strategy.

In major contests like CQ WW where there are no time limits it is still very useful to know your on time since endurance is a factor in participants' performance. The contest is 48 hours but if I can only physically tolerate operating for 42.5 hours, that matters. Therefore I track the time and report it.

I am not shy about disclosure when it matters.

I know contesters that deliberately hide whatever metrics about their contest entries that they can. Or they will wait until the log submission deadline. As more contest sponsors publish submitted logs after adjudication and publishing results, disclosure can be delayed but not prevented. 

I know a few of the reasons some do this but that's a topic I am not prepared to delve into. I've heard what I consider both good and bad reasons, keeping in mind that these are matters of personal judgment where there can be a diversity of opinions.

QRG.000

In the old days we had technology called "analogue". Our radios depending on it. Oscillators oscillated and ruled dials marked where we listened and transmitted. Or so we hoped. Calibration was mandatory, but with calibration standards of varying reliability we mostly just crossed our fingers when a rare DX station showed up near the band edge. With less stable oscillators, our VFOs might drift out of band while our attention was on the business at hand.

Analogue is mostly gone, pushed out by digital. Gone are the ruled dials and the frequent need for calibration. When the VFO says "21.033.91", we believe it. Indeed, if I arrange a schedule with you on 24.938500 MHz, we can both spin our VFOs to that frequency (or type in with a keyboard) at the appointed time and we'll find each other. We probably won't even have to twiddle the knob to make our voices recognizable on SSB.

Modern technology is a marvel. But being able to set up a sked at 24.938500 MHz is awkward; there are too many digits to remember. So most hams round it off to 24.938 or even 24.940 MHz to get rid of those pesky rightmost digits -- zeros are useful for doing that. Frequencies are much easier to remember when you can mentally ignore the trailing zeros of a precise frequency. 

Of course that reduces the available sked (or DXpedition) frequencies but, well, the bands aren't as crowded as they one were. If you run into QRM you QSY 5 or 10 kHz, precisely, and carry on.

That may be fine for skeds and DXpeditions, but what about other activity that isn't on repeaters, nets, digital watering holes, etc.? What should I do when I call CQ? Many hams will very carefully adjust their VFOs to, say, 28450.00 (or 28450.000) kHz and make their call. Only rarely will that least significant zero flicker, suggesting a drift of ~0.03 ppm or, more likely, a stray pulse from the optical encoder.

When you click a DX spot on the band map you are almost assured that you will hear the station if propagation cooperates and the spotter didn't make an error when manually typing the frequency. But few do that anymore, letting the software read the frequency, automatically round it to nearest 100 Hz and then broadcast the message around the globe. 

Even if the frequency is slightly wrong, you can assuredly wager that the majority of the click-and-call stations will all be zero beat, defying the DX operator to pull a call out of the bedlam. Oscillator calibration is that good. It's so bad that some software applications apply a random offset to the spot frequency to prevent zero beating.

That's one negative consequence of digital precision and there are others. Consider the station choosing a frequency on which to call CQ. An excessive zeal to punch in all those rightmost zeros can have unexpected effects. Most receivers inherently have spurious signals (birdies) and many stations must deal with RFI sources. Birdies are usually not on exact kilohertz frequencies, but many RFI sources are. These can come from various electronics or from commercial transmitters (e.g. AM broadcast), the latter of which do often operate on round number frequencies such as 910 kHz.

Notice that last frequency -- its second harmonic is within the CW DXing sub-band at 1820 kHz. Many of us have weak or strong signals on frequencies like that. Call CQ on exactly 1820 kHz and many station will hear you zero beat that AM carrier harmonic. It happens more often than you might believe. The smart operators deliberately choose a frequency that is not an exact kilohertz. They know that they will have better "luck" being heard.

I wonder, as do many others, why so many hams choose to "channelize" themselves when it is completely unnecessary? Is there an aesthetic to the practice that lesser mortals are incapable of comprehending? Are zeros pretty? I suppose beauty is in the eye of the beholder.

It's gotten so bad that I tend to do the opposite, deliberately. I'll pick a frequency like 21249.12 kHz to call CQ. A surprising number of stations will call me at 21249.00 kHz and then wonder why they are having difficulty copying me. I shrug and dial in the RIT when necessary.

The practice of channelizing is uncommon in contests. When the band is packed with signals you rarely have the luxury of choosing a round number to start your run. You narrow the filter and squeeze your way in between a couple of big guns to make your call. Those non-zero least significant digits are ignored for those 24 or 48 hours.

In our technological society we build exceeding complex devices and use them to improve our lives. Hams are no different. It is perhaps not surprising that the way we operate is influenced by that same technology, just as much as a pedestrian who blindly stumbles into the roadway with eyes fixed on their phone.

We can precisely set our frequency, and for many that means we must precisely set the frequency. Round number are attractive to many. I enjoy watching how technology affects people. It can be amusing. It's a guilty pleasure of mine.

40 Meter Wire Inverted Vee Reversible Moxon

My 40 meter rotatable reversible Moxon project is progressing well. However, it is not an antenna that most hams could contemplate building and raising. Recently a friend decided to build a fixed direction version of the antenna with inverted vee wire elements. It can be a good choice since it's lightweight and the two most important directions for contesting in this part of the world are northeast (Europe) and southwest (US). I therefore thought it worthwhile to spend some time evaluating its performance, in at least one configuration.

Years ago, I worked through the performance and construction of a variety of 40 meter wire yagis. This is an opportunity to add one more design concept to that old pile. I've avoided modelling this antenna in the past because the 90° corners are not accurately modelled with NEC2. It's close but it would require adjusting wire lengths after construction. NEC5 does better, and I will be using it throughout this article. It integrates very well with EZNEC.

Before we start, it may be helpful to mention general points about 2-element yagis with a reflector. These include wire yagis, Moxon rectangles and rotatable aluminum yagis, with loaded or full size elements.

• Maximum gain occurs below the lowest frequency within which the SWR and F/B are optimum. For most 40 meter antenna designs intended for CW use, the target frequency for maximum gain is typically between 6.950 and 6.975 MHz.
• Gain bandwidth is narrow. Although the maximum gain looks good -- typically around 7 dbi in free space -- gain in excess of, say, 6 dbi is typically less than 100 kHz on 40 meters. It is a pet peeve of mine that this is rarely mentioned when compared to yagis with 3 or more elements.
  
• Gain is reduced when the elements are not straight and parallel λ/2 lengths. This applies to Moxons, yagis with loaded elements (coils, capacitance hats, etc.) and elements with any bends. It is equally true of the antenna presented in this article.
  
• Inverted vees have a higher angle of radiation and greater ground loss than dipoles with the same peak height, including when they are incorporated into yagis. 
• 2-element yagis "see" the ground more strongly than yagis with more elements at the same height because there is more radiation directed up and down. A height of 20 meters for all parts of a 2-element 40 meter antenna reduces ground interaction to near negligible, but elements that bend downward, closer to ground, such as inverted vee elements, affect antenna performance.
  
• Copper wire elements have more loss than aluminum tubing. Depending on the antenna design, wire yagis have 0.2 to 0.3 db less gain due to resistance loss. The loss is higher at frequencies near maximum gain where the radiation resistance is especially low. For 2-element yagis with a reflector (including Moxons) that is at the bottom of the frequency range.
  
• Tuning of wire yagis is sensitive to wire gauge, material, insulation, proximity to obstructions and metal used for utilities and house infrastructure, and height of the element ends.

To simplify the design process I will begin with an ordinary Moxon rectangle in free space. It will be symmetric. which is necessary to reverse it and preserve performance. There is an implied switching system at each element centre, which will be described further below. Once that antenna model works as intended, the elements will be rotated to form inverted vees, and the required adjustments made. Only then will ground be added to the model. Proceeding in steps may take longer but typically leads to more predictable and better results.

Modelling the antenna with inverted vee elements and ground from the start complicates the process. Scaling elements that are not parallel to the X, Y or Z axis can make it difficult to maintain desired angles, lengths and see the impact of ground. Doing it is stages really takes no longer and we get to see the impact of bending the elements and the ground on performance. For a similar 40 meter wire "diamond" yagi, I wrote a spreadsheet to simplify the process. Here I'll do it differently, as will be described below.

The model at this point has the following parameters, which are in range of what is typical for Moxon rectangles:

• Boom length: 5.6 meters (0.13λ at 7.1 MHz)
• 12 AWG (2 mm) bare copper wire
• Element length: 15.04 meters
• Each right angle leg: 2.65 meters
• Gap between element ends: 30 cm
• Reflector element coil inductance: 1.25 μH
• Gain at 7.0 MHz: 6.33 dbi (free space), which falls to 4.6 dbi at 7.3 MHz
• F/B: 10.5 db at 7.0 MHz; 30 db at 7.1 MHz; 20 db at 7.2 MHz and 9.5 db at 7.3 MHz
  

The SWR is pretty good, but it could be better. I did a little optimization -- coil, boom length and element tip gap -- and I was able to lower the SWR slightly, at the expense of 0.1 db of gain. However, these changes are negligible and we can expect greater effects once the elements are folded into vees. The exercise was interesting but arguably inconsequential. Note that I calculated the SWR down to 6.95 MHz to highlight the impact of a low radiation resistance where gain is maximum.

Overall, the measured performance is about what one can expect from a wire Moxon. Making it symmetric and reversible has little impact. That's good.

I split the elements at the centre to make it easy to fold them into a vee shape. It is not my intent to try every possible interior angle, settling on 120° as the most common choice and one with typically good performance. Angles of 90° and less are strongly discouraged for any inverted vee or yagi made from them since the fields between element legs increasingly cancel. The interior angle will be less than you expect due to wire sag, so keep that in mind when you lay out the antenna on your property.

The lower radiation resistance reduces gain and can make matching to 50 Ω more difficult. This is a Moxon so we don't want a matching network at all!

The first change was to rotate the elements by 30°. There are significant differences. First, the SWR curve improved slightly. However, as expected, the operating range shifted upward by about 50 kHz. Also expected, the gain and F/B declined. At the bottom of its range, which shifted upward to 7.05 MHz, gain fell to 6.05 dbi, a reduction of about 0.3 db. F/B bandwidth remains wide, typical for a Moxon, but it never gets as good as for the rectangle. (You can scroll down if you want to see the performance comparison in a chart.)

A slight gain improvement of 0.05 db was achieved by decreasing the coil inductance to 1.2 μH, at the expense of a slightly worse SWR. Increasing the coil to 1.3 μH did the opposite, decreasing gain by 0.05 db and improving the minimum SWR to almost 1.0. Leaving it at 1.25 μH seems to be a good compromise. That said, environmental interactions will likely have a greater impact than small adjustments such as this.

Scaling a Moxon rectangle is not trivial. Each dimension has a unique role, and those roles must be respected when the scaling is performed. Yes, you could simply scale every dimension but the results might not be what you expect. Consider these points:

• The gap between element ends is critical to the Moxon rectangle's unique performance. I try to keep this dimension constant once I've decided on the geometry for a particular frequency. Small changes are okay but there can be surprises.
  
• Radiation is from the long parallel sides of the rectangle. Longer is therefore better. The fields of the symmetric and opposite inward legs largely cancel. Proper scaling requires that the ratio of their lengths is kept constant, but doing so requires changes to the boom length, element tip gap or both. Again, small changes usually have small consequences.
• The wire gauge also must be scaled for an accurate result. However, for small changes the effect of wire diameter is negligible and can be ignored.
  

For this design I kept the gap of the Moxon rectangle (gray) constant (green circle): 30 cm. Note that the scaling options have been exaggerated in the diagram. All show an increase in the size (lower frequency), but the opposite scaling should be obvious. Since this antenna is a reversible Moxon with symmetric (identical) elements, one scaling calculation applies to both elements.

In option A (red) the boom length changes but not the rectangle's long sides. In option B (blue) all dimensions are scaled equally. Both change the basic geometry of the rectangle, which can be detrimental when referenced to a fixed frequency. My preferred option is C (orange) since the boom length and inward legs are kept constant. 

All that said, it is reasonable to argue that this is much ado about nothing since the scaling factor in this case is small and therefore so is the potential performance impact. In practice the scaling option is more likely to be driven by construction and environment constraints, and that's perfectly fine.

You could bend the long sides inward as I did for the 2-element diamond vee yagi that I referenced earlier but that, too, alters performance, and not for the better. It is an option that may be appealing when the dimensions must be adjusted once the antenna is in place. The boom length may be more difficult to change.

Shifting the antenna's frequency range downward by 50 kHz requires lengthening the element by approximately 0.8%. The length was therefore added to the long sides. Adding 1% is even better since we are not changing the lengths of the inward legs; that is, the wire length changes are made in the long sides. 

The long side half-elements were increased from 7.52 to 7.59 m. A small increase of the reflector coil inductance to 1.3 μH slightly improved the free space SWR and put the frequency range where I wanted it, and equal to that of the horizontal (conventional) wire Moxon.

Gain and F/B of the inverted vee Moxon are lower. The gain reduction was expected but I was unsure how the F/B would be affected. The SWR bandwidth is roughly equivalent, which is one of the main attractions of the Moxon rectangle.

The reason for the gain reduction in free space is dominated by field cancellation due to the bending of the elements. That is expected behaviour for inverted vees. There is a small but negligible increase of wire loss. I did not delve deeper into the calculation to determine why the F/B declined. It has approximately the same shape across 40 meters but with lower numbers.

The differences are not huge. Gain of the inverted vee wire Moxon increases towards the top of the band but is otherwise within 0.5 db of the horizontal wire version. F/B is even closer except for 100 kHz mid-band where the horizontal wire Moxon excels.

Out of interest, I added figures for the rotatable reversible Moxon that I am currently building (T-hat in the charts). Its gain compares favourably while the F/B is little better than the wire inverted vee Moxon. This is despite the negligible wire loss of aluminum tubes. Performance of the rotatable reversible Moxon is also somewhat reduced by the large T-shaped capacitance hats that keeps the elements short in comparison to the copper wire Moxon antennas modelled here. 

The SWR curves for all 3 antennas are close enough that I did not bother to plot them.

Those performance figures are for free space. When placed above real ground, the impact will be about the same for the rotatable Moxon and the horizontal wire Moxon. However, that is not the case for the one with wire inverted vees. 

The elevation plot compares the wire reversible Moxons at a height of 20 meters (λ/2), which is a good height for a 40 meter yagi. They are more similar than might be expected from the free space figures. Ground in these models is EZNEC medium ground.

Expect the relative performance of the inverted vee Moxon to decrease at lower heights and to approach that of the horizontal rectangle at greater heights as the influence of ground increases or decreases, respectively.

Let's move on to several construction details. These are suggestions rather than rules so feel free to improvise. First up is the boom. 

If the antenna is mounted on a tower, the approximately 5.6 meter long boom could cause problematic interaction with other antennas on the tower. A non-conductive boom is preferable but difficult to make strong enough, even with a rope truss. A stiff fibreglass joint between aluminum tubes will halve the conductor sizes and greatly reduce interactions with all but 6 meter antennas. Alternatively (as one friend of mine has done), use a short aluminum boom with ABS tips (or other non-conductive materials.

The second item is tying down the ends of the inverted vee elements. Although the antenna is mechanically complex compared to a conventional wire yagi, there is at least one method that is quite simple. A rope connects insulators at the element tips. The outward tension of tie-down ropes from the rectangle corners stabilizes the geometry and is as strong as the ground anchors. Trees or other convenient supports can be used to keep the ropes out of harm's way.

Finally, there is the switching system. A total of 3 DPDT relays are required, one on the boom and one at each element. SPDT relays cannot be used since both conductors of each coax section must be switched. The boom relay switches the 50 Ω feed line to what is the driven element for the selected direction. The default direction for the Moxon should be the one that is used the most. The lengths of the coax to the elements are not critical and do not need to be equal. The element relays select a series coil (to make the element a reflector) or the 50 Ω coax to the boom relay. 

Coil Q is not critical since its inductance is small. Even so use a coil design program such as K6STI's Coil to ensure a Q of at least 300. That's a reasonable design objective. For example, a coil that is 1.5" long, 1.5" diameter, 7 turns and 10 AWG copper wire, with 1" leads, has an inductance of 1.3 μH and a Q over 400. It should be enclosed to prevent rain and ice from affecting its characteristics.

In the default direction all relays are idle, using the NC (normally closed) positions. When the antenna is reversed, all the relays are energized so that the NO (normally open) positions are used. The control cable may be able to use the common ground (coax shield and/or tower), depending on how your station is wired. It can be dispensed with entirely using a bias-T circuit. Be sure to use relays adequate to the power level in use and never hot switch the relays.

A common mode choke can be integrated in the enclosure for the boom relay, or you can place one at each feed point on the short connecting coax runs to each element. The former should work well since the less than 3 meters of connecting coax is likely to have a high common mode impedance at 7 MHz.

I hope that this article has given you a few ideas to consider should you want a reasonably simple antenna with gain for 40 meters. As I mentioned at the beginning of the article, a friend of mine is building this antenna and I am curious to learn how well it works. The boom and switching system are installed but he might have difficulty fitting the wires within the property lines.