SX-28 further inspections

Some day had some spare time (why it happens so rarely... :)) and decided to have a closer look into the new SX-28 (new in my shack, it is nearly 70 years old and is probably the oldest thing in my home....)

Disassembling is not very difficult task - if you remember the weight around 20kg :)

Inside I found some work that needs to be done. 

The capacitors in the power supply look newer than 70 years but not sure. Were they blue in that time?

Transformers don't look new but luckily seem to work correctly.

Most of paper capacitors are wet and covered with oil.

Chassis is mostly in a very good condition - probably radio has been stored in dry and nice conditions.

Variable capacitors don't look too good. This is a problem because probably it will be difficult to find similarly mounted ones.

Elements are mounted in "3D" mode (not on PCB) - it will be very difficult to replace some elements. In the worst case I will have to dissasemble everything and build back using new elements.

Some potenciometers required cleaning.

VFO section from the top. Tubes belong to VFA, mixer and IF amplifiers.

I had some problems to find out how tuning works. Usually could not find a proper frequency. I have measured the VFO frequency and now I know how it works. In fact it is not as bad as I was afraid - I have to set the main dial to the "dot" on the scale and then the secondary dial shows more or less correct freq. Not bad...

Finally I have prepared list of elements I want to replace and slowly starting looking for them...

New - very old - baby...

I have a new very exceptional radio... I have been planning this for years - maybe not particularly this model but was looking for something with vacuum tubes and possibly older than my father...

And finally this week I became a happy owner of such beautiful baby...

Additionaly I have a RCA speaker - no idea how old and where was used. Just looks great !!! How it sounds... scroll down...

Will require small repairs and realignment. Possibly also some tubes/other elements will have to be replaced.

And how it sounds? Just listen ....

Recorded with 3 meters wire antenna located inside my room...

It's over...


A few days of preparations (less in last year - finally everything is ready), three days of building antennas and station, 24 hours fun and 6 hours of station disassembling.

Every year I promised myself that it was the last time. But this is like wandering in mountains - when you walking up you wonder why the hell you do it and whose idea it was. But when you reach the top you forget how difficult it was and enjoy the moment. Also a few moments later when watching pictures or films you start to plan a next trip. I have exactly the same with IARU contest. Maybe somehow this time I'm a little bit less exhausted than I used to be. No idea why - I built more antennas than usually, it was terribly hot this time, I lost a windscreen in the car and my rotator died and I had to manually rotate whole mast with antenna. So why I'm still alive this evening and even able to write? Again no idea.

Maybe because the highest result I have ever made - 272 Qso and over 70.000 points (the highest was 254 and 60.000). Maybe because I had expected bad propagation and worthless contest and it was pretty good and interesting? It seems that there were less dx stations (less South and North America, no Japan) but probably more local stations...

I started on Thursday after finishing my work hours. It took 2 hours to assemble Spiderbeam antenna. Would be faster but discovered that the glue between o-rings and Spiderbeam tubes lost strength and this had to be fixed (for now temporarily by tape but later will have to glue it again).

Friday was antenna day - at the EOD (we use this in the bank = End Of Day) all three antennas - Spiderbeam, GP and Delta 40m were up. I checked SWR with VNA and also listened to some bands on KX3.

Saturday morning - just before the contest - some latest amendments to Delta 40m and building the station in the car. I was more or less in the middle when realised that I miss some cable - USB cable to connect K3 to computer.. Luckily I took one more additional USB-Serial converter and this was used instead. Next year I should make a check-list with all cables listed (on my current one I have just one position: "cables"...).

I have to do some final tuning to Delta 40m antenna as was tuned before in different place and on different height. Surprising was that when I attempt to change the length of the bottom leg the SWR was only higher... Then I incidentally lowered the middle of the bottom leg and SWR dropped to 1.2. Finally I shortened the bottom leg for around 150cm and lowered middle of it fixing to the mast and final SWR was close to 1. Strange - never heard about such method of tuning delta antenna.

At 2pm (12:00 GMT) I was ready to start. 

This year contest was quite "calm" - I could reach on my QRP 5w most of stations I could hear. Of course not all of them - 5w is 200 less than 1kW and best antenna will not fix it. Probably also strength of my signal was much weaker than all the stations with 1kW but during the contest everybody puts more effort to receive even weak stations.

Following advices from Rick DJ0IP ( I had some very interesting conversation with Rick related to my new Delta antenna) I tried to not use the antenna tuner - all my antennas are pretty well tuned and according to Rick tuner introduces additional and unnecessary loss (minimal but always...). Probably no big gain but at least I dint have to ensure that tuner is properly tuned on every band (I guess K3 does it automatically but I was always checking).

Shortly after midnight when I tried to turn antenna to some direction the rotator stopped following the orders.. It appeared that can turn antenna right but couldn't do it to left direction :( I tried to review all connections, tuning unit, rotator but everything looked OK except that didn't work. Finally I had to disconnect rotator from the mast and till now I was "manual rotator" for my antenna. It affected whole next day so instead of turning antenna for every station I was pointing antenna into one direction and then trying to sweep through all three bands 20,15 and 10m. Sometimes when some specially valuable station appeared (multiplier) I was running to antenna and manually set desired direction.



The contest finished on Sunday at 2pm. Next 5 hours I spent on disassembling everything and putting back to boxes. Now these boxes are waiting at home for the right place (radio I have to install but  when I think about all these cables that need to be connected again...) 

Power usage for this year (seems to be much less than previous years)..

Rotator & notebook:

Radio & panadapter:

Green: AGM 107Ah (not charged additionally)
Red: two 70Ah car baterries (charged additionally 3..4x 20 min running engine). Btw: such 20 minutes was able to lift battery voltage from around 12V to 12.6. It really helps...

And finally ..

This year results are promising...

However it always depends on overall performance of all participants..

That was disaster... At least...

The preparations as every year. Maybe easier because everything nearly ready. Year by year created some kind of procedure - month before visit my friend farmer (Herr Muller) where in language I dont speak we agree all the details.

It looks more or less like that:

- "Guete Morge Herr Müller" :) (big smile, good morning)
- "Guete Morge" (big smile too). "May day may day ?" (means more or less: "Would you like to use my field for your strange antenna activities again?"
- "Ja!" (means yes)
- "Wenn?" ("When would you like to do it again?")
Here I try to explain in my very bad Züri-Deutch when this is going to happen.
- Then we usually finish with universal:
- "Ok?" - big smile
- "Ok!" - big smile

I have to add that I don't have to pay for this and the only profit Herr Muller has from my "antenna activities" is nice cake (made by my wife) and some bottle which came from Poland (I'm Polish) - usually some special polish one...

So as every year I came by car fully loaded of our "stuff". Spiderbeam (20-10m), vertical (18m pole with radials) used on 160-40m. Radios: K3 and KX3 however never learned working SO2R so 99% of time use K3.

After assembling all the antennas, radios, food corner etc the contest starts. At the beginning everything was fine maybe except lower activity than expected. Late evening I noticed that something is wrong with the antenna - I have rotator mounted on the ground and rotating all the mast with Spiderbeam. Due to ropes which hold mast in possibly vertical position on the top there is free loop of cable that lets the mast rotate. And this loop was too tight, too small or whatever. I saw that whole mast behaves strangely when rotating and realised that something is seriously wrong. And that was in the best "activity" time when still there is many stations from Europe/East and already there are some stations from Americas.

I decided to put the mast down and fix the cable loop. Unfortunately 1. I'm always alone, 2. mast is 18m high and quite heavy, 3. all operations I have to do standing on the 1.5m ladder, 4. I need to use wrench to fix the mast, 5. there was quite strong wind that day

I released screws holding the mast (while standing on the ladder) and then ... the wrench went to the ground... So I was standing on the ladder holding the mast (I could not go down more than 20..40 cm because the wind was dangerously bending whole mast) and the wrench was laying on the ground 1.5m below.
I was waiting 5..7 minutes hoping that someone will pass but nobody did. I realised that I'm not able to hold the mast any more... was too heavy. So I lowered mast around 1.2m down not even looking up, went down, took a wrench, went up, lifted mast, fixed it and then finally look up. Uff - was still there.

The whole exercise with lowering the mast and lifting it up again took around 2..3 hours (please try to do it yourself - you will understand) and I lost probably the best time of that evening.

The rest of the contest was also far from fantastic. The only absolutely fantastic thing was QSO with Australia on QRP  SSB - 5W. That was my first Australia ever and after the contest I emailed the operator to ensure that that was not a dream. Was not !! I didn't think it is possible at all (I mean QRP SSB). The signal was quite strong and he didn't have very big problem to copy my callsign. That was a great surprise.

Finally I finished with around 26.000 points (previous year around 60.000) so I have no chance to be a member of "Top Ten" for this year. Ok, next time I will be better prepared and maybe finally learn how to use two radios in the same time (which I promise myself every year since I have two radios, hehe).

Picts and films will come later.