Tuesday, 10 April 2018

Spring is here.

Finally all snow is gone.
So now I will start the evaluation of the dual pol "rainmaker" again.
Will also perform some sun noice measurements on the present system as reference when I make the rebuild to open wire feed.
The Italab amp build progress is slow at the moment and non ham related work is needed att his time.
Need to prepare the summer car and also spend some time in the forest cutting down trees before the sap goes up too much.

Did not work the CR2 dxpedition.
Heard them fairly good and regulary but pol was not playing along so they never heard me.
Lets hope the Z66EME dxpedition will be easier to work.
Besides that I have not worked so much lately.
The activity is mostly at max dec and when any dxpedition is qrv.

Will try to update more regulary in the future but nothing has happen lately so no point in posting nothing.
Got a PCB for the ON4BCB DIY version of the ON5JFL controller from Ronny SM7FWZ and is sourcing Component to complete the build.
Use at the moment VK5DJ controller and its working well but want PWM for the motors and it is an option in the VK controller but it seems easier with the OE5 one with direct support for a H-bridge.
Furthermore it also have built in position data for more noice and quite sources.

Saturday, 24 March 2018

Spring is comming.

Finally we got some warmer weather and the snow is melting quite fast but still we have some 20 cm in the garden.
Have only made some work on the Italab amp but not so much actually.
Have spent a lot of time bead blasting the rims for the Buick and will powder coat them and mount new tires as well and will also do some work on the engine later.
I also need to start cutting down trees to use as firewood for the next winter and that is somewhat time consuming.

The only activity lately was the TD9CHR dxpedition who I worked and now awaits the CR2EME dxpedition which is about to start today or tomorrow.

Will continue with the amp and I am right now cad a PCB for the arduino nano with all external circuits to fit within a screened casing including decoupling caps and series inductors on all input and output connectors.
Will hopefully mill the board next week so I can test the controll circuits and see if it behaves as I want.

Sunday, 25 February 2018

Wintertime

We have now entered a real wintertime here.
Temperature is at highest -5 during the daytime and down to -10 during nighttime and more or less powder snow falling everyday.
In total we have more then 40cm of snow and even driving the snowmobile is difficult in some places.
Closer to the coast line they have had really much snow during the past few days and below is a picture when I went to work Monday morning.
Did meet one car and it was OK as long as you did not stop and just kept moving all the time but the guy I met did stop so he got stuck.
Road to work Monday morning. 













So all antenna work are closed down and last week I was hit by the annual flu so just some minor work has been done but nothing related to the EME station.
The antenna has at the moment not so much snow on it and matching is good and the snow falling now when its cold is very light and will blow away.
Looking forward to the Guatemala dxpedition next weekend and I exchanged the preamp last week as it was not the best and some of the lost RX performance is restored.

Was active during friday and saturday eavning but activity was not that high.
Dubus contest was running and a lot of CW activity and I hrd a lot but I am not really used to the RX of the Anan radio in CW.
Feels like I have difficulties adjusting for a good AGC behavior together with bandwith for weak CW RX so I need to use it more to find my settings.

The heat sink I have planned to use for the Italab 70cm amp is huge and I need to cut it in half.
I got two of them with the plan of use parallell FET amps for both HF and 2m.
Will cut it this week and build a casing for the whole amp.

Sunday, 4 February 2018

Snow Again.

Need to rename my dual pol test antenna to the snowmaker instead of rainmaker.
From Friday afternoon to Saturday eavning we got more then 30 cm of really sticky snow.
All antennas are cowered and even the 80m dipole was more or less laying on the gound as the end spring was pulled to maximum length du to the wieght of all snow stuck to the antenna element.
So no antenna test this weekend and it will be cold the remaining of the week so the snow will stay on so John, the WW will be in use the whole week.

Will keep myself occupied with indoor work for some time now but have plenty of unfinnished projects to start up again and I also have a Italab KW pallet on 70 cm I bought a few month ago that also needs to be put together.
Will use the PQL controller as base and also PQL low-pass filer and directional coupler but everything controlled by a ON7EQ controller and display unit.

Thursday, 1 February 2018

The Rainmaker

Long time since the last update but the weather has not really cooperated with the efforts of antenna evaluation.
The YBN 25 el and 14 element combo ( The Rainmaker) is completed and I and John ZS6JON has done some promising tests.
John transmitted on his Rainmaker and I could easily detect him when he transmitted on the V 14 el part and I RX on my 8 times 25 el. but nothing what so ever when he used the Horizontal 25 el.
Dan HB9Q had his RX chain and reported to Livecq and the results corresponds very well to the estimations.
So an overall very successful first test of Johns antenna.

My Rainmaker




















I just listened on my as I did not fit a TX relay to the setup and at the time there where only EU stations active and the pol was close to H all the time.
Did hear both SM5EPO and S51LF easily on the single 25 el and compared to the 8 times 25 el showed actually quite small difference.

First decode is with the 8 times 25 el and the last two with a single.

















My conclusion is that the single works well and I have something not fully OK in the 8 25 el array at the moment.
We have had a lot of rain this fall and winter and its not completely impossible some has made its way into a connector or cable.
It really does not matter as the antenna works OK and I have already planned to rebuild the feeding to open wire feeds.
The vertical parts that I also most likely will add will have coaxial feed-lines so I need to check what has happen with these to avoid problems in the future.

The forecast is that the temperature is going down but I hope I can make some more test during the weekend when the dec is still high and window to the US and more shifted polarization.

Sunday, 21 January 2018

More snow.

Some more snow has eliminated all possibilities for antenna work at the moment as can be seen on the Pictures below.
Some detuning of the array as well but not so dramatic actually and it´s still below 1.5 in VSWR.

















































Removed the relay and preamp box last week and checked it out and the preamp was gone but the relay just needed a light cleaning and nothing actually burned. Will try to get it up again during the week as the temperature is increasing according the the forecast.
Will also make a change in the preamp switching and exchange the P-channel FET switch to a relay connected so the preamp signals grounds when TX to avoid any problems with blown preamps in the future.

Tried to get my 2m transverter setup completed last week but discovered low gain in the system and when measured the transverter it seems like that Gaas Fet was blown too.
So now I need to source a CF300 transistor too but found them at Giga Tech

Bought a huge car subwoofer amplifier last summer at a public garage sale very cheap and ofcoarse it did not work when arrived home but I had allready suspected that so it was a gamble.
Put it on the work bench last week too and after some support from a very nice and helpfull service technichian from the German manufacturer, it now works perfectly.
It can put out 3KW max at 1 Ohm and at 2KW out  it needs 180A on a 12V rail so plenty of power.


Tuesday, 9 January 2018

Preamp and relay failures.

The weather since last update has been either rain or cold so no further antenna work has been done.
Tried to work some after new year but the preamp blowing and relay blowing is a constant issue.
Exchanged the preamp as said in last post but blew it after some 10 CQ´s again and built a new relay box containing a Russian REW14 relay as main relay and a Siverslabs as RX isolation and termination relay but blew that setup too including the preamp after some 10 CQ´s or so.
Have not yet removed it form the mast as the temperature has been to low but will do so as soon as it rises again.
So I am not 100% sure the relay broke but the VSWR is like 7 and no preamp.

The REW14 relay should withstand the power without any problem at all and my first thought was that the amp is oscillating or something strange as it does happen in the middle of a TX sequence and not while switching.
Tobbe SM7EOI had an idea that maybe the power inside the PA is causing the switch that controls the RX/TX relay and preamp to switch on occasionally due to high RF levels while transmitting and this could for sure explain the preamp and relay failures.
The switch is a P channel FET switch that is located within the PA enclosure so I will try to design a circuit that triggers on the control signal and transmit to see what is happening.
Or I will design a new system for controlling and switching completely.

Another thing I discovered was that when I blew the last relay the PA indicated high VSWR but did not shut it off.
It still continued to TX and I had to stop with the JT software.
This should not happen but still it did so I need to check that in the PQL controller circuit.
Believe I have experienced something similar on the 2m PA as well so maybe there is something needed to be reworked.

Besides from that we have had our share of the flue and now the work has started again.
Will try to find an isolated 30-40mm bar or tube so I can mount the dual pol yagi on an az/el rotor before the next high declination time which is in 2 weeks so I can monitor the difference in signals from the moon with dual pol.
I think I have a boom to make a second of these antennas but don´t think I will find the time to make that.
Could be interesting to see but I have some other things to attend to first.

Have had a discussion with John ZS6JON and he is planning to build a similar setups both for himself and a Ham colleague.
As the weather is like it is here in the winter time, my plan is to do the conversion of all my 8 antennas with vertical parts when the weather gets warmer and when I have planned to also lower the mast and change to open wire feeds.
So most likely he will bet me and manage this before as his weather is more favorable at the moment.
Looking forward to his work and information and will support them as much as I can.