My friend Michael (SV5BYR) recorded our RTTY QSO we had yesterday in 30m band. I post it as a season greeting card to all of you.
Warm wishes for Good DX, Health and Happiness during 2011… strictly in this order!
This is the QSL card of Arcala radio, the biggest ham radio station in the world. I got it recently confirming our contacts in several bands and modes, mostly for QSO made during contests. Note that I never asked a QSL from them, but a big station is big in everything.
Some times it is very difficult to imagine what is going on in the other side of the pile up. Take a look to this sort video that Vicky (SV2KBS) sent me from Kermadec (Raoul island) recent major dxpedition.
Come back safely Vicky!
A new addition to the blog. This is a real time local weather reading. There two links to click in the right side bar of the blog in order to watch a lot of details of local weather parameters.
These are just some examples of what you expect to see.
All these are made with the help of Cumulus, a very effective software of managing weather stations. Mine is a DAVIS Vantage PRO2 actually. So please enjoy.
Last weekend, 2 great Greek amateurs made a quick visit to our island: SV2KBS (Victoria) and SV3AQR (John). I had spoken many times with them through the radio but I never had the opportunity to meet them. Tasos, SV8YM brought them to my second QTH, the well-known cottage, and we spent a lovely couple of hours having a friendly chat about ham projects, antennas, dxpeditions, etc…
Speaking of dxpeditions, during the meeting, Victoria made an amazing disclosure, announcing her participation to the upcoming great ZL8X event this November. Victoria is very active recently. (Falkland, Easter, Lord Howe, to name some of her activities). So Kermadec will be a new success of hers. Well done Vicky!
PS: In the photo from left to right: SV2KBS, SV8YM, SV3AQR, SV8RX
Every year I join the Marathon on 6m band. My intentions are not to get first, as I have not the equipment I would like to, but to have fun and keep an eye on propagation differences year by year as we approach to the circle 24 maximum. Actually I have achieved the following scores:
| Year | Countries |
| 2007 | 42 |
| 2008 | 52 |
| 2009 | 61 |
| 2010 | 67 till now |
It is obvious that propagation is increasing steadily on magic band. This result is expectable of course, but it is nice to document it by numbers.
I have to mention here an exceptional QSO I made a couple of days ago with JL8GFB (Man) 9200Km away, using a ringo vertical and 150w. This is exactly all I have in my second QTH I was that morning. I really enjoyed this contact. Here is the cfm in a chat dialog after QSO done.
“06:43 SV8RX George JL8GFB Man did you copy any other Greek stations this morning?
06:44 JL8GFB Man SV8RX George tnx QSO, only u and Costas here
06:45 SV8RX George JL8GFB Ok Man Tnx!
07:03 SV8RX George JL8GFB Man You have to know that you have very sharp ears. I used only 100w and a ringo vertical antenna!
07:04 JL8GFB Man SV8RX FB George many tnx for info!”
So nothing is impossible in magic band! Good openings.
Just in case you need a TX ground to operate your linear and the CAT/LIN connector is engaged in CAT position (Menu 020).
That was exactly my complain with this Yaesu transceiver! I prefer to use CAT commands to manage all transceiver operations from my computer especially when I operate the digital modes. No way to PTT the linear with such configuration. I had to use a foot switch to do that. Not so neat as I would like. I read several proposals in the internet addressing this issue. None of them was satisfactory for me. So it took me a lot of time till find a solution.
Finally the resolution, even not obvious, is quite cool and easy! In the back panel of the radio there is a female stereo 3.5mm jack called ACC (number 5 in the schematic). You can use this to have TX ground for your linear without sacrificing CAT! If you are interested just follow the procedure.
Open the top cover of the FT-897D and locate the jumper in the back right side (circled in the picture). By default this jumper is set in “TX REC” position. Change it to “TX GROUND” position, as sown on the board, and your work is done. Now instead the TX request feature, described in the operating manual (not very useful to me), you will have a nice independent PTT for your linear.
Finally you need to wire a male stereo jack as seen in the schematic.
“Hi, I am Yoshiki, 9 years old, living in Yokohama Japan.I have JA-call sign (JF1UCV), and QRV in Japan.I am visit KH0 and am enjoying the contesting from AH0BT with my dad/W1FPU.I like contesting, that's very COOL than Nintendo-DS.-------I am planning to join next CQ WPX SSB contest as SOAB Rookie category. Please call me !!!”
That is exactly how he describes himself in QRZ.com. It was a pleasure meet him as KH0UA in the CQ WPX contest last weekend. Personally, I was surprised by his skills dealing with the huge pileups and giving 4 digits numbers. I have a feeling that he will doubtlessly win the Rookie category this year.
Working the test I have to mention the thrill of exchanging numbers with the legendary OH8X, probably the biggest club station in the world!
Good propagation, big numbers!
I spent last weekend in my second QTH. I am not prepared for 6m band operations there. Shame on me! You can imagine my surprise to hear ZS6NK (Paul) on magic band using my 160m dipole. I worked him as well as ZS6JON (John) with these wires and 50watts. I checked that I could hear them on my mobile antenna too. For a moment I heard Z22JE (Dudley) but not worked him. What a propagation! TEP was missing for years. It seams that it came back for good. If you think how many possibilities has an RF signal to reach your receiver, you can realize that everything is possible.
Schematic taken from http://www.hamqsl.com/solar.html
Last week was too busy. Propagation on upper bands is great recently. What a relief after so may year of quietness. On the other hand a several events and tests took place that are worth to mention. Let start with the QSO between ISS and a Greek school of Athens. I was stacked to 145800 to listen Timothy. J. Creamer KC5WKI speaking to children and replying all their questions. Great signal from the spacecraft up to 59 to a vertical antenna. And great job from RAAG that organized and contribute to make this contact real.
Finally my friend Spyros (SV8CS) came back from Montichiari, where he participated in the recent CTU as a lecturer. He has with him his daughter Anna (SW8NAC), who was the younger attendant of the Contest University. More details for the event you can find in this blog. From the left: K3LR and his XYL,IK2QEI YL, SW8NAC and SV8CS.
This is the oldest device in my shack. It has about the same age with me. It is a signal generator made in fifties by TESTGEAR (ACTON) LTD, a small family business company. (You can find info about them following this link ). It came to me totally unexpectedly. It previously belonged to an Englishman ham who past away recently. A relative of him, who is a good friend of mine, she picked up from his shack and thought to bring it to me as a gift. I have not to say how much I appreciated this gesture. Thank you Moira. It was in a good cosmetic condition but I was curious if it was still working after all these years. So I unscrewed the back to see what it looked inside. With a great surprise I found out that the interior was still in excellent condition too. Shiny tubes and pretty capacitors! Take a look! What a construction? This is the pre-transistor era.
…And finally it is working properly as at the first day out of the box, still producing decent signals. Wow!
Now, there is a real question. What can you do with it when the modern transceivers have a stability of 0.05ppm? Practically nothing. Just admire….
This is an update by SV8YM to the recent mod he uploaded to mod.dk. So I have to post it for anyone that could be interested.
“After my first experiences with this problem, I had proposed a simple preventive measure, consisting of adding a gate series resistance to the driver unit, which apparently suffers from instability with destructive results in many cases.This update is the result of further study of the problem. It attacks the problem in a more efficient way,taking more measures to reduce the instability but also taking measures to prevent the destruction of the driver unit.The update consists of two parts, the first about improving the original modification, and the second about taking extra steps to ensure better stability and protection of the transistor in the driver unit. One can perform just the first part which is very simple. The second part is quite a bit more complicated and requires lifting the PA PCB and performing more alterations and additions to the circuits - but it offers considerably more safety.
PART 1: IMPROVING THE FIRST MOD'S EFFECTIVENESS
The first mod required the addition of a 10 Ohm resistor in series with the input (gate) of the PD55015 LDMOSFET in the driver unit. After studying the circuit's behaviour and experimenting, I finally , changed the resistor’s value to 1 KOhm (see schematic below) which offers much more stabilising action with just a modest decrease in power output (~5%). So, if you have already done the first mod, change the resistor to 1000 Ohm. If you haven't yet done it, refer to www.mods.dk for the full description of the first mod,but use an 1000 Ohm resistor , instead of 10 Ohm. Resist the temptation to tamper with the service menu to compensate for the small ~5% loss in output power – it's really not worth it.
PART 2: ADDITIONAL PREVENTIVE MEASURES
The second part attacks the problem from different angles. It requires considerably more effort and skill. This part is for the more experienced technicians, so detailed instructions (e.g. "lift the PA PCB by desoldering... and then..." etc., will not be given here. Please be extremely careful.
1) Modification of the drain - gate negative
feedback network of the driver unit
Lift the PA PCB and remove the driver unit. The drain - gate negative feedback network flattens the gain vs frequency response of the broadband driver amplifier stage. It uses a capacitor (C101,10nF and a resistor (R102, 100 ). Change the capacitor to 0.1 μF, 50V. This lowers the range of frequencies for which the network provides negative feedback, stabilising the amplifier there also. Apply a thin film of silicone grease to the heat sink's surface and tighten the driver unit's fastening screws well when replacing the driver unit.
2) Addition of an extra bypass capacitor
This part requires adding an extra tantalum bypass capacitor across C305 (470 F, 16V PA UNIT). Locate the capacitor's leads (see photo and schematic diagram) and solder a 47 F / 35V tantalum capacitor across the electrolytic. Observe the polarity!!
3) Addition of a driver unit protection fuse
Adding a fuse to the 13.8VDCline feeding the driver transistor's drain improves the chances that even if the instability occurs, the transistor will survive. (There won't be any fireworks and smoke, in any case!). Locate L302 on the PA UNIT (see the schematic diagram that follow for diagrams and photos). Unsolder it and transfer it to the of the PAUNIT (as shown in the service manual), soldering only the lead that connects it to the node with C305 and L301. Then solder an 1.5 A, fast-blow 20mm glass fuse to the free lead of L302 in the way shown in the photo, soldering the other end of the fuse to the PCB trace that L302 used to connect to (it's the "b" line with 13.8V on it). Use a small piece of wire to solder the fuse to the trace. Don't locate the fuse elsewhere using long wires! Do it exactly as shown. Lay the fuse flat on the PCB.Use a small piece of thick paper or plastic sheet to insulate the end of the fuse soldered to the free lead of L302 from the PCB trace under it. After you have finished, cover the fuse with a piece of electric tape to prevent shorting the 13.8V line when replacing the rig's covers.
FINALLY, 4) Lowering the idle current of the driver unit
In order to lower the gain of the class A driver stage, also reducing
its thermal burden without seriously affecting its linearity at the RF
drive level used, we can lower the idle current via the service menu. The service manual procedure sets the idle current of the driver unit at 1A. Reducing it to 0.6 A produces no ill effects on linearity (as measured in a two-tone test in SSB). Follow the procedure at page 4-3 of the service manual, "transmitter adjustment". Set the current at 0.6 A as per the instructions and exit the service routine.
This concludes the mod. Good luck! Enjoy using your IC7000!”
The diagrams that follow refer to the fuse addition
Some QSO are exceptional. And that was with Angelo this evening. It is several days now that propagation permits easy contacts with USA stations in 15m. So it could usually be a routine QSO, but Angelo surprised me. He answered my call speaking Greek! This excited me enough to have a quick search in the net for his call. What I found, it was a really impressive site of his. Live log in real time, audio clips of QSOs, S-meter watch, statistics and many other interesting info. It is unbelievable what one can do with internet nowadays. We had a very friendly chat with Angelo and I hope to meet him again soon. As for you I recommend a visit to his site: (http://w8ern.myqsx.net/). It is really worth it!
Last years I always participate in big contest events. Except the fun it is a great opportunity to check propagation and collect some precious wanted slots. So I had been anxious for CQ WPX RTTY test especially this time as the sun showed some evidence of awaking recently. Finally I found out that it was my best ever try with 852 QSO in the log and scoring about 1,420,000 points. Actually in 15m I logged more dx QSO than European. This happened for the first time. The 10m band was soulless though. Anyway it seems that propagation definitely is increasing. So good DX to all of you.
I have just received an email from my friend Tasos (SV8YM). He describes what is the reason of a usual issue on IC 7000 transceivers and what is the cure on his opinion. Besides he will publish this mod in a proper site I think it is very important to post his whole letter in my blog. It is not a secret that I suffered from this problem twice.
“IC-7000 driver amplifier self-oscillation problem
The IC-7000 is a very popular rig, and rightly so, since it combines many desirable features in a small, light transceiver. I was surprised when some of my friends reported that their rigs had literally gone up in smoke!
Actually, one of them had died TWICE with the same symptoms (scorched driver unit). Later I found out that this phenomenon has also been reported by other users on the Internet. The whole thing reminded me of my experience with my FT-817 (which, by the way, still goes on strong).
As I undertook to fix my friends' rigs, I decided to implement the same self-oscillation preventive measures to their IC-7000s, as the failure mode had a strong resemblance to that of my FT-817 final amplifier.The problem probably lies with self-oscillation of the common driver stage of the TX amplifier chain. A series resistance
of a few ohms is placed in series with the input (gate) of the FET amplifier, by cutting the appropriate PCB trace. The photos and schematic explain the modification. It is very simple to do, and can help prevent this "smoking" failure mode, without any side-effects and at negligible cost.
THEORY OF OPERATION: This mod lowers the Q of the copper trace circuits feeding the driver amplifier's input, therefore
quenching any tendency of the stage to self-oscillate at some VHF frequency, with destructive results.
IMPLEMENTATION: After removing the covers, locate the driver unit's input trace (SEE PHOTO), cut it carefully and scrape the solder resistant enamel to expose the copper surface. Then, solder an 10Ohm (or so...) SMD resistor across the cut of the PCB.That's all!
IMPORTANT: After you have finished, carefully check and clean all of the springy ground clips on the PCB. Also, clean carefully and apply a thin protective film of grease or vaseline to the points on the covers where the grounding clips of the PCB make contact. The deterioration of this grounding scheme due to oxidation of the inside surface of the covers has been proposed as a possible reason for the driver unit self-oscillation and destruction.
Disclaimer: This mod requires delicate SMD soldering. Perform
at your own risk. Although the mod is based on proven engineering
techniques and worked perfectly for me, I can't guarantee that it will
work for you.
Tasos Thomaidis sv8ym@raag.org”
Thank you Tasos for all. BTW see in the photo below, how the driver unit will look like if this failure happen to you too. My IC-7000, after mod, is working perfectly so far.
Soon after I found his QSL card in my eQSL inbox. I wish you many DX Kohji…
