I have had some issues with aiming the antenna as the feedback from the G-5600B has been very flaky – I found out that it’s very likely [...]]]> I decided to put the antennas up and take part in the ARRL contest as the WX forecast was good – specially so late in the winter.

I have had some issues with aiming the antenna as the feedback from the G-5600B has been very flaky – I found out that it’s very likely a dirty pot in the back of the control unit. Then my beloved amp blew a fuse .

I’m hearing quite well – but sometimes it’s like people dont hear me!

I’m sad to have missed Japan and other Asia stations – but I have houses obstructing the east path to the moonrise! Now there is a clear plan forming to try to get VK/ZL/JA in the 2m EME log! I might have to wait for the moon to be in a northern declination – and perhaps move my QTH temporarily.

From my current QTH I dont see the moon from about 280° – 0 – 80° – and I always have to have at least 6° elevation.

update: Thank you for all your patience ! this was really fun – just under 100 QSO’s total in this try!

All QSO’s logged here on this page: http://www.tf3cy.is/eme-qso

73, Benni TF3CY

As I needed [...]]]>

I needed a power amplifier for 6m EmE, so after looking around I found that my father TF3T had 4 unassembled AR313 kits from Communication concepts lying around, he also had a PCS4 splitter/combiner. This he bought some 15 years ago. They are based on the MRF141G “gemini” tranisistor. http://www.communication-concepts.com/ar313.htm

As I needed QRO asap this summer, I decided to build two modules and combine them with a combiner I already had. Also I did not have a powersupply to drive 4 modules at the time. The amp was built and worked well on 6m. It was not until this winter I got interrested in 2m EmE, the plan was changed and now I would get the amp working on 2m as well. This really just meant building a small relay board to switch between two low pass filters.

Power supply:

basic specifications:

• Input voltage: 220-240V (jumpable)
• Output voltage: 4x 28v
• Output current: 4x 25A max (limited at 23A)
• Maximium power rating: 3KW
• based on 723 voltage regulator + 20x 2n3055 output transistors.
• 150ms slow start is accomplished using control from a PIC 16F877A microcontroller. (using 10Ohm resistor)
• LCD display that shows current and voltage per channel and cuts out the PA and Power supply if over voltage or over current status is detected. It’s bit slow as the processor is running at 5Mhz so the reaction time is around 10ms.

So basically this is a 3KW linear power supply built around a 3KVA toroidal transformer woven by Airlink transformers (UK based). It’s a heavy transformer, 17Kg and I got it delivered to Newcastle where I was on a business trip, bought a small cabin-case for it and took it through BA flight to London and then to Iceland. There is a loophole in the on-board luggage rules at BA, only dimensions, no weight restrictions.

As the power amplifier has 4 PA modules, each operating at 28v/22A I decided it would be easier to build the power supply with 4x 20A outputs, rather than 1x 80A output.

I’m using the standard 723 regulator with a 2n3055 in a Darlington pair configuration, 1 driver and 5 bypassing.

The PSU has a slow start using a relay that shorts a 10 Ohm after around 200ms

The PSU is controlled by a PIC control board that uses it’s 8 AD inputs to monitor voltage and current. I use a PIC 16F877A as I just happened to have few lying around. Current is measured using a standard op amp in a differential configuration.

I decided to use a inductor on the output and use the resistance in the 16AWG wire as the shunt, both for current sense and current limitation.

for now, here are some pictures, I will update this later perhaps with schematics if someone is interested :

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The amp is based on the AR313 . I have already the amp working at 600W, but I’m adding two more modules to give a combined power of 1200W.

here are pictures of the current work:

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[View with PicLens]

It’s not pretty, but in tests it puts out 1200W on 6m. I don’t have the ability to fully drive the amp on 2m , but it’s going up to 600W, but I see it’s not very efficient on 2m – that worries me.

The 2m low-pass filter can been seen there in the back, it uses RG142 coax cable as capacitors, close to 1pF per 1cm, so each of the capacitors is 18cm of RG142. It was modelled in Elsie, and used a miniVNA analizer to test it.

The amp is being built from the ugly design of my first 600w 6m amp,  so I look at this as a test bed for the moment. I have a nice chassis that I want to mount the amp in later. I’m also working on a nice sequencer to control relays and the pre-amp. That is coming – but I think I will test the amp on some nice EME over xmas.

update: 22/12/2010:

Tested the amplifier on 6m – 1200W without saturation, can overdrive to 1500W. Power supply heats up well and after a 50 second xmit the transistors are cool, only thing worrying me is the 30 ohm balancing resistors are heating up -(50-60°C). Luckily I have 10x 25ohm 50W on it’s way from ebay (russian made). I could only drive the amplifier up to 200W on 2m but the Yaesu 723R is just to weak to drive the amp, I need around 40W on 6m to fully drive the amp, but I only get about 6w to the amp due to some mismatch in the splitter on 2m.

I’m here with my brother, TF3SG and father TF3T.

We will be QRV on 20m thorugh 160m.

I will post some pictures if my internet connection stays on. We are slow moving, trying to work the pile-up’s

Now on a JT65A “RUN”

fun but slow !

I’m using 20w into [...]]]> Okay, after making a fool out of my self for few times, I called my fellow ham TF3HZ and asked about the reporting exchange used in JT65A on HF. He talked about “right-clicking” in WSJT, and then everything made sense.

Now on a JT65A “RUN”

fun but slow !

I’m using 20w into a 43ft vertical with a small tuner at the base. It has very poor ground, but I have been thinking off pulling back on power as my reports are usually around -10.

I hope I’m being a good op, as I don’t send a final 73, I usually go into CQ TF3CY after getting a 73 from the caller. I think it’s more efficient (not very amateur’ish) as I will not lose a whole 2 min. I have been killing time while at work, so if I just dissapear from the spectrum, it usually means that I have to do some actual work!

73, TF3CY happy hunting

I raised a 40ft vertical in the garden with very poor ground radial system, put a small tuner at the [...]]]> Any hams looking for QSL cards from me, don’t worry you will get them. I had to print a new card, and well, very busy summer and been away from home almost 2-3 months.

I raised a 40ft vertical in the garden with very poor ground radial system, put a small tuner at the base, let my wife key the transceiver while on the phone, and tuned. The tuner was set on a target freqency on 80m, after trying some SSB phone CQ’s wihout anyone answering, I decided to try JT65A. No luck on 80. But I tuned the rig to 20m, and there where some real good signals, at least nothing like the EmE signals. Pressed AutoTune – and it would actually tune. I guess I was perhaps getting few milliwats out, as I was using two tuners in a row, and one was trying to match a vertical on 80m

But I got confused.. everyone is sending signal reports, and I tried one QSO and gave OOO as report. Not sure if that was correct – anyhow, we did not finish the QSO. sorry N9GUE got your R-16

but JT65a is amazing – or I should have expected it – as I have been using it for EmE. These where huge signals compaired to the faint traces I have been trying to decode.

After not having completed one QSO using the portable EmE setup, I was thrilled to compleate 3 QSO’s when the moon was between 7 to 3° this evening. First QSO was with Mick, W1JJ that I had already worked, but that confirmed [...]]]> I’m pretty sure I made the first 6m contact from Iceland to New Zeland!

After not having completed one QSO using the portable EmE setup, I was thrilled to compleate 3 QSO’s when the moon was between 7 to 3° this evening. First QSO was with Mick, W1JJ that I had already worked, but that confirmed that the homebuilt amplifier and antenna was working. Also this was the first QSO on the current transceiver, small but nimble Kenwood TS-570D. I had a sked with K6QXY and I copied him very well and the QSO was over in 3 minutes. I started calling CQ  and in the next sequence I got a decode from Rod, ZL3NW!!. We finished the QSO quite quickly. I don’t know how do descibe it, thrilled does not even come close.

Strange, sitting in a ice cold van in the middle of nowhere, watching a computer screen feeling this excited!

I’m going to try to get EX6EME next morning, then use the evening to try to complete more QSO’s!

here are some pictures of the current setup:

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[View with PicLens]

here is a screenshot FROM Rod ZL3NW:

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[View with PicLens]

I would like to work as many stations as possible, so please email me 

I can only work the moonset – so fire up GJTracker and see if you can work me.

73 de TF3CY