Information about larsthunberg.se

Domänen larsthunberg.se ägs av Lars Thunberg, Sollentuna. Kontakt via e-mail   lars(snabel-a)larsthunberg.se

Om du letar efter ”rätt” Lars Thunberg kan jag nämna att födelseort är Mellösa utanför Flen och födelseår 1972.

Jag finns även på Facebook men är inte så aktiv där:

För arbetsrelaterade kontakter hänvisar jag till LinkedIn:

This is the homepage of Lars Thunberg in Sollentuna, Sweden. Amateur radio callsign SM0TGU.
e-mail lars(at)larsthunberg.se
For information about satellites and amateur radio please see this page where most of the info are in english.
My linkedin page is http://www.linkedin.com/pub/lars-thunberg/1/442/769

Amateur Radio

Rot2Prog powered with Dell 19.5V adapter

Important update!
When using automatic control from PC then both the elevation and azimut is controlled (moved) at the same time. It seems that the Dell power adapter can not handle the current amp spike and turns off (overload protection I guess).

I have now return to using my 13.5 volt power supply.

I have been powering my Rot2Prog rotor controller for my RAS rotor with 13.5 volt. This means that the rotor turns slow. My 13.5 volt power supply also has a very high idle consumption of 10 watts.

I changed the power supply to a standard Dell power adapter – LA130PM121 19.5V 6.7A PA-1131-28D1 130W. It can be found very cheap. I just cut off the power plug and connected the wires from the Dell adapter to the Rot2Prog controller wires.

Now the turning goes MUCH faster! The Dell adapter also has a very low idle consumption – under 0.5 watt. So it can be connected all the time. What I can see there is no interference from the adapter on VHF and UHF.

I highly recommend using the Rot2Prog controller with an old computer adapter. Below is a short video of how fast it is turning.


IC-705 operation and satellite memories

Please see the following posts at AMSAT-SM about IC-705 satellit operation and memory files/settings:


IC-705 Mic 3V or 8V?

In IC-705 it is possible to set the MIC output voltage to 8V instead of default 3V. I have done some tests and I do not hear any difference with the standard microphone HM-243. What do you think?





Amateur Radio


Tested new mode today, JS8CALL, and got first QSO with SM4INV:

Read more and download at http://js8call.com/

Amateur Radio IC-705

Satellite Memory File for IC-705

This is a memory group file over satellite frequencies for Icom IC-705 and CS-705 software. It is not complete and will be updated. Feel free to use it, change and add.

The memories for FM transponders are used like this:

  • Channels named with satellite name, for exemple ”PO-101”, are used in split mode. This channel can be used when using the IC-705 for portable operation or without an extra receiver .
  • Channels named with satellite name and Uplink, for exemple ”PO-101 Uplink”, are used only for uplink (not split). This can be used with software like SDR-Console v3 (external radio) or if you have an extra receiver.

Import the memory file into CS-705:
Note! Be sure that you not overwrite anything in your IC-705 when cloning. Make a backup of your current settings!

  • Create a new memory group
  • Mark this new group
  • Choose File->Import->Group and choose the .csv file
  • The memories will now be imported to CS-705
  • Clone to your IC-705.

IC-705_SatFrqMemGroup.csv (Downloaded from AMSAT-SM website)

Amateur Radio IC-705

First satellite QSO since 1993

Today, 2020-11-11, I made my first satellite QSO since 1993 (when Oscar-13 was alive). My two QSOs was via PO-101, IC-705, 10 watts output to 13 el X-Yagi.


IC-705 vs RS-918 with FT8

I was interested to know how my RS-918 (a mcHF SDR HF radio clone) performed with FT8 compared to my new IC-705.
I have done a series of test. Very non-technical tests, without any promise if this is the truth. But it was possible to repeat the results several times. I have done the following:

  • RX test: 10 minutes with one radio, switch antenna and then 10 minutes with the other radio. Then counting number of received stations.
  • TX test: 10 minutes with one radio, switch antenna and then 10 minutes with the other radio. Then counting number of stations that could RX my signals.
  • Test done on 20 meter (14 MHz) and 40 meter (7 MHz) band during day and evening time.
  • 5 watts output was used. The RS-918 needed a little PA calibration to reach 5 watt.
  • The tests has been repeated three times on both TX and RX.

What I can see is that the number of station received are similar, in the image below the RS-918 actually received more stations but in the other tests I could not say that one of the radio was better than the other.

IC-705 RX 40 meter
RS-918 RX 40 meter

In all tests, the IC-705 performed better. The output (5 watts) is the same but it seems that the IC-705 have some more punch in the modulation. I do not know, I have not investigated this further…

So, for some ”local” FT8 contacts in Europe I can use the RS-918 but if I would like to hunt some DX I will use the IC-705 with 10 watts.

IC-705 TX 40 meter
RS-918 TX 40 meter