QRP from Rab Island (2009)

This note will look old, since more than one month has passed since we've returned back home. But at least will report what I have done in 2009 on Rab island.

I had planned to take part to Apulia VHF QRP contest from the top of Kamenjak mountain. All I could carry was the 4 element Yagi. The day before the contest I had forgotten headlight on and the car battery went flat dead. Fortunately I could get it started for 100 HRK from the local service station.

The contest day I went up to the top, prepared the setup and called for two hours beaming Italy (organizing country) without receiving a single reply.

So I decided VHF was not the way to go and I switched to HF 20m. I moved the 9m fishing pole away from the car so it could support the 20m EFHW antenna radiator, tuner laying on the rocky ground and one counterpoise.

I did get odd looks from hikers/bikers/tourists passing by, but nobody asked a thing.



The band was crowded, signals were good, so I tried some QRP SSB contacts. I could work one station, others were having pile up (it was too hot up there for fighting). Finally I fired up the netPC and called CQ on PSK31. This mode was more productive.

The game was soon over since we were expected for lunch. PSK31 operations continued from home with 100% battery power (RTX and computer) and 20m EFHW antenna out of the balcony.



Overall I managed fewer QSOs than last year, but I did not take part in any contest. There was no pile-up on my calls even if I was from a IOTA/IOCA reference.

I missed the warmth of CW contacts but I enjoyed these operations nevertheless.

Alpe Adria VHF 2009: mission aborted

Every year I can hardly wait for Alpe Adria VHF contest, the first Sunday in August. After my best performance of year 2008, I wanted to improve the setup.

I started building a Yagi with 4m long boom: on an empty mountaintop it should still be possible to handle it. On Friday the boom was ready but not the rest (dipole, elements, ...). Moreover one battery pack is not suitable anymore for my FT817, so I had half power reserve than last year.

I decided to keep things simple and short: same antenna as 2008 (5el on 2m boom) and just one battery pack. I would not be able to beat my own A.A. record but at least to improve my operating skills.

On Sunday morning I drive up to Colle delle Finestre (2100 masl), there are some clouds in the sky but don't look too serious:


Once at Colle, I see dark clouds climbing fast from the other valley, and my target destination already covered. I change plan: I'll go to a closer peak at 2500 masl.

At the beginning of my hike I have to pass a barrier, I pull my backpack, I pull ... crash ... damn! What was that? I put the backpack down and the 2m long boom sticking out of it has broken in two. I can still build a 3 el antenna or fix it on the fly once on top. So I continue hiking.

Air gets colder. I feel something on my hand: it starts raining.


Far away I hear a couple of sounds that look like a thunder, or a motorcycle roar.

-> abort <-

I walk back to the car, take few pictures and a strong storm begins. It lasted two hours, so I am glad I decided to return home rather than wait for clouds to pass by.

See you next year, Alpe Adria!

The word of experience

Finally I put my Tek 7603 oscilloscope into service. A friend (the one from optical experiments) needed to verify a circuit he's building. Those were routine tests, not troubleshooting.

While probing for a couple of signals (ca 3 kHz, 15Vpeak) I noticed a strange random behavior: either the signal was as expected, or was passing through a high-pass filter (only spikes instead of edges).

The first problem was easily tracked down to a cold solder joint since it showed properly when touching the generating IC.

The second ghost was trickier: all joints were ok. It was a digital signal... where was the high-pass effect coming from? While checking for continuity with an ohm-meter backwards from target to source pins (with ICs removed!) I came to a homebrew connector with 2.54mm (1") pin headers ... on the corresponding pin tip I could not get a proper contact, while at the pin base it worked alright. Very suspicious. I touched the pin and asked right away: "what did you do to it? Glue?"

He admitted that the building instructions showed a way to hold the strip while soldering: put it into a roll of packing tape. !!!!!!!!!!!!!!!!

NDB ZAG

After shooting the long wave NDB (non-directional beacon) CAS, I happened to have the chance to shoot another NDB in Croatia.

It is NDB ZAG, whose coordinates can be found on Internet. Unfortunately I had forgotten to plan in advance the road to get close to it, so I asked my brother back home to send me some info via SMS. It turned out that Internet is far more detailed than any other paper map I could locate and I failed to reach the NDB location.

I had to blind shoot it while driving at 90 km/h on the high speed road going to Vrbovec. It sits North of that road. The digital SLR helped to get the antenna into the frame.


This second picture is cropped from a 10Mpixel image and digitally zoomed 3 times.



After these shots I tried without success to get close to the beacon site, but nothing. Village names on Internet are not written anywhere in the real world! Now I've checked through a web service with satellite pictures how to get there, so perhaps I'll try a second approach on our next trip to Zagreb.

BPSK splatters

I had not seen such a bad signal yet in my digimode life. 30m, BPSK63, 2009-06-18. I did everything on my FT-817, IPO, ATT, volume control but to no avail: I could still see the signal twice and with many distortion products.



I worked him with 1W, so his signal was indeed very strong. I mentioned the bad IMD (-15dB) but nothing changed. I gave RSQ 555 but should have been 591.

A couple of hints:
Make sure the ALC is not active when transmitting. With ALC=0, just below its ALC>0 point you are already transmitting at full power. After that ALC reduces your audio drive, creates non-linearities in the TX chain and sends out splatters. Moreover with ALC>0 your measured power is distributed amongst all unwanted signals, thus you actually reduce your main signal power (see below)!

Transmit above 1500 Hz in the waterfall. This helps not to send the signal twice. If you sit at around 1000 Hz, your TX SSB bandpass filter will let through 2000 and 3000 Hz too, so you'd transmit any harmonic generated within your computer of first TX audio stages. Better stay between 1500 and 2000 waterfall Hz, and retune your RTX main dial. This is a clever hint that I have not seen mentioned anywhere.


"below". A proof that his distorted 50W did no more than my 2.5W comes from pskmap: we both reached the same stations, including one in the US East Coast.

Console switch

Have you ever come across a keyboard+mouse+VGA mechanical switch? I have found a 4-way model (4 computers, 1 actual device) and couldn't resist to look inside it.


It is routing about 25 lines. The solderwork look done by hand and with just one color of wire! Hats off!

Any use in the shack?

2 x Balcony QSO

Funny enough to report it here. Last night I was working 30m PSK31 when a Mr. Enzo from Paris came back to my CQs... after the usual data exchange it turned out we were both using an antenna on the balcony. Him 80W, me 5W, 100% copy on both sides. Moreover he is Italian, according to his qrz(dot)com profile.

I think that was my first BPSK31 2xBalcony QSO. HI.

It is almost time to open a club and give awards, HI.

EFHWA tuner quirks

For the upcoming Summer holidays I decided to try something new: an End Fed Half Wave Antenna (EFHWA). Since all operating conditions will be known (same place of last year), I should be able to compare two different antennas.

I chose the EFHWA because it is reported to have a decent radiation angle even when low above the ground. This antenna has a high impedance between 2500 and 5000 ohm depending on the way it is installed, so it requires a matching device.

Given I will be using QRP, I built a transformer on T50-2 code with 3:27 turns ratio. This 1:81 step-down impedance transformer matches 50 ohm to ca 4000 ohm. With a polyvaricon capacitor it tuned between 6.2 and 22 MHz.

Then I reduced the turns ratio to 3:25, so that it would match a 3300 ohm antenna, in between the EFHWA expected Z ranges. This increased the resonance to 9-26 MHz since the secondary inductance had reduced. Good 30 to 12m coverage, I wouldn't be able to throw a 20m of wire for a 40m EFHWA anyway.

Ready for boxing the tuner... surprise! The tuning range has now shrinked to 11-26 MHz! I have lost 30m when fitting it into a plastic box. This means that the maximum capacitance or inductance available has reduced (I did shorten wires of 2-3 cm if that matters), or both. Need to get back to it and try something different.

For those interested: I found out the tuning range using an antenna analyzer (MFJ259B) and connecting a 3k3 resistor in place of the antenna. Gave full capacitance and looked for the SWR dip with the 259. Same at minimum capacitance.