Q: When is an amp not an amp?

A: When it's defined and measured differently, by global consensus.

The scientific community has redefined several System Internationale units of measure, including the ampere, in an historic agreement signed at Versailles in Paris this week.

Previously defined in theoretical terms involving measuring the forces of attraction or repulsion between two infinitely long conductors in a vacuum, the amp is now defined more pragmatically in terms of the passage of a coulomb per second, in other words a specific number of elementary charges (electrons or protons) passing through a conductor in a precisely specified period. 

The charges and the time are both defined as SI units and are measurable, hence the amp is also measurable ... although it's not exactly easy. Whereas the measurement of time is pretty well sewn up by measuring the frequency of energy changes in caesium, scientists are currently developing solid state devices to control and count the passage of individual electrons.

At least, that's my understanding as a radio amateur, a former scientist with an interest in measurement. I'm not a theoretical physicist. I don't count electrons, I put them to use.

Hourglass loop antenna

In "The Hourglass Loop Antenna" (QST December 2018, pages 35-37), John K4ERO describes the construction of two-wavelength wire loop antennas for three VHF/UHF bands. These are tall and thin with an insulated crossover in the middle, making a kind of hourglass shape. As described with the feed point in the middle of the bottom side, they are horizontally polarized.

Although I'm not interested in the VHF/UHF bands, I like loops. John's simple design is said to have a few dBs of gain by compressing the vertical radiation pattern towards the horizon ... which might be useful on the lower bands. If the size is practical, I could hang an hourglass loop from a tree or tower. It's also said to be a good match to 50 ohm coax feeder using just a ferrite choke balun.

John didn't provide any formulae in the article to calculate the dimensions for other bands, so I set about reverse-engineering them from the dimensions given:

By my calculation:

• Wire length = wavelength x 2.05 
• Loop height = wavelength x 0.85
• Loop width = wavelength x 0.18

So, for the 6m band, an hourglass loop would be roughly 5m tall by 1m wide. This would be simple to construct and hoist into place from a tree, using aluminium tube or bamboo spreaders top and bottom. It could be made lightweight enough to risk using, say, a fibreglass fishing pole as a support. Two identical hourglass loops might even be interlaced at 90 degrees to each other, perhaps using two feeders or a relay to connect one feeder to either antenna to switch direction. Alternatively, the antenna could be twisted with the top and bottom spreaders held at 90 degrees to each other, providing a nearly omnidirectional pattern for, say, a 6m beacon.

On 10m, it would be 8.5m tall by nearly 2m wide. This is also feasible for suspension from a tree, using a reasonably strong top spreader. Again, twisting the lower spreader relative to the top one (perhaps using twine to hold them in place) would make it closer to omnidirectional.

Down on 30m, the antenna would be about 25m tall by a bit over 5m wide. It would be trickier to construct and hoist from a tall tree, not impossible but getting impracticable. A one wavelength square wire loop suspended between 2 trees would be simpler and probably about as good, perhaps better being higher off the ground and further from the foliage.

As a trial, I might try making one for the broadcast FM band - 6.21m of wire in an hourglass shape 2.58m tall by 0.54m wide should improve reception of the scratchy stereo radio stations, although vertical polarization might be better with the feed point moved to the centre cross-over.

Thanks for the inspiration, John!

What does UP mean?

A DXer friend on the CDXC reflector mentioned that VP6D was sending "UP2" but not actually listening 2 kHz HF! Golly! Imagine that! 

Depending on the DX op and the situation, such instructions might be dead right, dead wrong, irrelevant, deliberately misleading ... or something else entirely.

“CQ UP” with no number is clear enough: it simply means "Please use split, transmitting HF of me, not here." Usually.

Sometimes it means the exact opposite: “I’m listening simplex while sending UP because I want to work split … but I have tuned back to my own frequency or accidentally turned off split due to being tired and emotional”. That situation generally sends the Up Police into a frenzy when good DXers notice he is listening and working people simplex so they call him on or close to his TX frequency for a QSO, but the kops are too frenzied to notice and too inept to understand that THEY are the QRMers.

Even more ‘fun’ is the unfortunate situation where the DX sends “UP” while tuning his transmitter HF. Sentient listeners (those not using ridiculously narrow knife-edge filters) will immediately notice from the chirpy signal or random tones that his TX is moving or jumping around … generally because he is using a K3 and has accidentally slaved the TX and RX VFOs, or again has accidentally de-selected split. After a while, his frustration mounts, repeats increase and sending gaps lengthen as he notices the confused pile is no longer responding to his transmissions. Finally he glances down at the radio or DXcluster, realizes what is going on, panics as the penny drops and stops sending for a bit as he desperately shouts for help to “sort out this bloody radio”, whereupon normality is resumed. He may or may not return to his original TX frequency. This mess used to happen regularly on most multi-op DXpeditions using shiny K3s, new and unfamiliar to many. It’s less common today, perhaps because it is patiently explained to everyone during briefings on the long voyage to the DX QTH.

“UP1” (on CW) generally means the same as “UP” …. so why bother sending the “1”? If sent occasionally, it may be a hint that, having been systematically tuning through pile, the DX has ‘reset the cycle’ by retuning his receiver close to 1 kHz up. It’s a signal to experienced DXers to follow suit. It can also mean “I’m working split, so spread out and I’ll find you: leave the naïve/hopeless DXers to their bun-fight exactly 1 up while the rest of us spread out to make more leisurely QSOs”. On rare occasions, it can mean “Call me 1 down” or “Call me on my secret pre-arranged calling frequency, friends”. 

“UP [gap] 7” is another way to send a message to the deserving: the 7 (or whatever) is deliberately delayed so that the majority of eager over-excited me-me-me callers are already transmitting (salivating like Pavlov’s dogs) so miss it, or else assume it is some other station sending random nonsense. The delayed message works even better on SSB if the instruction or code word is muttered quietly in the DX station’s native tongue: as soon as one of his friends ‘gets it’, word goes out to the others and the pileup splits in two. Clever DXpeditioners can keep this charade up for some while, returning to the non-deserving callers every so often to ding the dinner bell and give the impression that they are about to be fed. Clever DXers listen hard and watch carefully to figure out what's going on.

I'll leave you to figure out for yourselves what "UP [gap] DN" really means.

“Up 5 to 10” on SSB may mean “call me up 5-ish but, chaps, it really would help if you were to spread out a bit from there, thanks awfully”, or “up 5 or up 10”, or “up 5, 7.5 or 10”, or “I’m tuning around the pile above me vaguely in the approximate vicinity of two to ten VFO clicks HF, trying desperately to pick out any recognizable phonetics” … or something else entirely (maybe “Oh boy, just listen to that huge pile!", the bunny-in-headlight moment that strikes every DXpeditioner). In a big pileup, it simply means “UP”. In a small pileup, or sent by an inexperienced DXpeditioner, it means “UP precisely 5, no more, no less”. Same with "Up five to fifteen" and so forth: for some it's a literal instruction, for others merely an indication.

“UP [anything]” can also be whatever leftover message has been programmed into the keyer, voice keyer or PC, remnants of a previous user. Like “CQ TEST”, it sometimes helps to send a longer CQ call for a micro-break while logging the previous QSO or sipping coffee, to trigger the RBN, or to signal the cycle-reset. Normally, though, the full message would either not be used at all by a slick op, or truncated after the “CQ” with a deft tap on the ESC-key or PTT.

For such brief messages, that’s a whole lot of meaning!

Stay tuned, folks. My next topic may or may not be “QRX5” …

73

Gary ZL2iFB

The joy of CW

I just enjoyed my slowest CW QSO of the year so far: I worked WA4KIT on 17m CW. Allen has only been using CW for a month so was QRS, hand-sending slow and steady with very few mistakes, mostly corrected, hence easy to copy. I found he copied my ropy hand-sent CW just fine with Farnsworth spacing which seemed more natural for me, sending characters at about 15 WPM but with extended gaps for him to do the mental look-up and (I guess) writing each character on a scratch pad. He told me I was the first station he had worked outside the US. I pictured him grinning ear-to-ear! So nice to make someone's day. It's 40 years since I learnt the code and I remember how taxing it was to concentrate hard, so I'm full of admiration for new ops making actual CW QSOs, not just sending minimal info but listening and responding to the other end. Fantastic! I'll send him a QSL card to commemorate this momentous event.

SAC CW contest 2018

I wasn't able to dedicate much time to the contest this year (as always, to be honest) but enjoyed my Sunday morning digging out Scandinavians on 40m and surprising them from the Far Side.

Band      QSO   Points   Multipliers
------------------------------------
80m          0       0       0
40m         40     120      25
20m          5       5       5
15m          0       0       0
10m          0       0       0
------------------------------------
Total       45     125      30

Claimed score: 3,750 
Single-op (assisted) All band High power

Although I won't set any records, it was good to catch some genuine DX.

QSL cards still valued

This week I received a beautiful QSL card to add to my album:

I've been DXing long enough to recall the poor quality of QSL cards common in the 1970's - often generic designs in one or two colours of ink, shoddily printed on cheap thin card with low resolution. They were par for the course, at the time. I had some printed myself. Home-made cards were common in some parts of the world.

Despite the limitations, some hams got creative with the designs: cartoons were quite popular, supplementing or replacing the more traditional country-outline-map-with-a-dot, or the plain and simple callsign banners.

In the 90s, full colour photographic cards gradually became more common. The standard design of the age was a photo of the operator, seated in the shack in front of the radio. Some were holding a microphone or Morse key, perhaps wearing headphones or turning the VFO. A few had kids or pets sitting on their laps, while computer screens and keyboards gradually appeared in the average shack-shot.

Too tight to get any printed, for some years I sent picture postcards of the local area using sticky labels for the QSO info - initially hand-written then computer printed.  

This century, as LoTW has grown, cards have declined in number but increased in quality. Most of the cards I receive today are unique custom-designed and professionally-printed in full colour. Nice! Some, such as VP8ORK's, feature arty shots by hams with a flair for photography. A few DXpedition or special event station cards, such as VP8ORK's again, are folded or stapled multi-page cards with further photos, sponsors' logos, info about the stations and operators etc. in addition to the basic QSO info.

I still get a buzz from QSLing. I enjoy reading the cards and appreciate the effort and expense by the senders. Hand-written comments - even something as simple as a scrawled 73 - catch my eye.  Cards confirming genuine DX QSOs are valuable, especially if I lack the corresponding LoTW confirmations.  Cards from friends or particularly challenging QSOs make me smile.

The best QSL cards deserve their places in my album. I ration myself to just one card per DXCC country, and relish leafing through the album either to insert new cards or just to remind myself of all the fun I've had over the years in this fine hobby.

Chasing grids

I've finally passed 3D2EU's scores in the ARRL International Grid Chase: it has taken months of effort to catch them and take the lead in CQ zone 32. Five excellent ops were QRV from Rotuma Island for ~3 weeks, making ~30,000 mostly CW QSOs covering ~1,000 grid squares.  

Overall, I'm ranked 106 in the grid chase with a total score of ~5,000, a long way behind the global leaders' awesome totals of over 20,000.

Some chasers may be running FT8 robots and multi-station setups to max-out their rates. Several are keen contesters. I can't compete directly with that level of activity and dedication ... but I'm giving them a good run for their money in terms of working unique grids. So far this year I've made ~13,000 mostly FT8 QSOs covering ~1,100 unique grids placing me 20th in the world - not bad at all with ~40,000 chasers! Logger32 conveniently highlights new grids this year on its band maps which suits my aims as a Far Side DXer. 

FT8 on 80 at ZL dawn

Mornin' all.  As usual I'm up before dawn, keen to see whether 80 and 40m are open for the greyline.

For over a year now I've been DXing on FT8 mostly, using a second widescreen monitor dedicated to the FT8 software (JTDX in my case) and Logger32's bandmaps.  While I'm busy working on the other screen, I can keep an eye out for new DXCCs on each band and mode, new grids, FOC members, old friends and other interesting stations.

Right now at 6:30am (1830z), 80m is looking quite lively with about thirty FT8 signals on the waterfall and a stack of mostly European DX stations listed on Logger32's UDP bandmap.  They are stations I have decoded - not just DXcluster spots from other DXers.  On both 80 and 40, I'm using an 80m long square wire loop suspended in the clear between two handy tall fir trees.

With the amp on, I'm running about 200 watts out ... which evidently isn't enough at this moment to break through the EU QRM at the other end. None of the handful of EU stations I've called so far have responded, as is often the way. As the dawn approaches, the conditions generally improve and for a short while the greyline path opens sufficiently for DX QSOs.  Hopefully.  

As I write this, I'm CQing with nil response, like a fisherman casting into a promising part of the river ... oh, hang on, my first bite of the day: JA2LWA.  Good morning! He's -6 dB with me, and gives me -14 (so much for my 200 watts!). Now another strong JA gives me a fairly weak report. Evidently 80m propagation is not brilliant today although PSKreporter shows I am being received across the dark areas of the globe (the blobs with times) all the way to the Far Side:

So, I'll try 40m instead and gradually migrate up towards 17 or 15m during the day, then back down to LF at dusk - my regular daily DX routine.

73

Gary  ZL2iFB