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.

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.

Amateur Radio

First HF portable test

First portable test at my garden. FT4 on 20m. RS-918 5 watt to an end fed half wave antenna. Very good result, easy to make QSOs.

Amateur Radio

Trapped End Fed Half Wave (EFHW) for 15/20/30 meter

Inspired by this excellent article from PeanutPower I decided to build a resonant End Fed Half Wave (EFHW) antenna for portable use. My antenna is designed to be resonant on the digital sections of 15, 20 and 30 meter ham radio bands.

All measurements done with NanoVNA.
You can click on all images below to get a large image.


The 1:64 UNUN is made just like this post that I have published before, with the 100 pF capacitor added later for better 15m SWR. You can see that the SWR is higher on high frequency but it was possible to get a good SWR on 15m, when antenna wire was added.
BNC connector are used because that is my standard for HF and portable connectors.

UNUN without 100pF
UNUN with 100 pF
UNUN with 100 pF
Test measurement of UNUN with a 5k ohm resistor

Sotabeams QRP Pico Traps

Traps used are Sotabeams Pico Traps. It took me a two hours to build, unfortunately I lost the small SMD 100pF capacitor so I used bigger ones. I also need to unwind one turn for each inductor to get in resonant.

14 MHz trap
21 MHz trap

Setting up the antenna (wire) sections

This was the most time consuming part. First I used an online antenna calculator to get the sections length. These are the calculated length but I added aprox 50 cm to each before mounting:

Frq (MHz)Sections (m)
21,1 MHz6,68 m
14,1 MHz3,4 m
10,1 MHz3,9 m

Begin with the highest frequency (band). Get the antenna up – measure – down – cut wire – up – measure – down – cut wire…. until you have good SWR for all three bands.
Wire used are from Sotabeams.

This is the result. As you can see very good on 20m and 30m.
On 15m SWR is 1.68:1 – OK but not perfect.
Note: after adding a 100pF capacitor at the input on the UNUN the SWR on 15m got flatter and lower.

Antenna SWR for all three bands

This is how the antenna can be used:

And everything ready to go!

Amateur Radio

Minikits EME144 SMA relay

I have been using the Minikits EME141 relay kits for both VHF and UHF for a long time but I never did any measurements. Using the NanoVNA I now have done a sweep for HF, VHF and UHF.

HF is excellent, VHF and UHF are very good. See image below (click for large image). Note that the SMA connectors during measurement can add some losses. Insertion loss is -0.76dB at 435 MHz.

The EME144 is now replaced by even better releays.