MSK144 QRP and ES0UG (/8)

This week some people from here work from Estonia under the call ES0UG (and ES0UG/8). Since there are no good ES conditions currently we tried MSK144 meteor scatter. I did not think there will be a lot success since i can only run 25W ERP. But finally i god some of their CQ.

ES0UG/8 calling CQ in MSK144 from KO18

During my lunch break i did not have success. In the evening we tried again and were able to complete the QSO to KO18 field within about 1.5h.

Since yesterday evening the crew is qrv from the next island in KO19. We tried again in MSK144 and this time we had bursts rather early. It still took more than an hour to complete the QSO and this time i have a nice screenshot.

ES0UG in KO19

Since i did not expect that it will work at all i am quite happy with my first two QSO via MS. I also got some spots from G3SHK. Many thanks!

Another great ES opening

This evening great ES opening to EI and G. And a surprise in between with S01WS.

It started in CW with EI4DQ in IO51WU and then i worked:

In the screenshots 23cm is displayed as QRG. This is because i use a wrong transverter setting in my SDR software which is taken over by WSJT via hamlib.

finally worked S01WS

big signals on 4m

4m ES opening June 1st 2018

This evening pretty good ES opening into several area of Europe. Also the 4m band was in quite interesting condition.
I worked some EA station + OH + SP all in FT8. Seems most of the stations are in this mode now.
Signal were pretty amazing strong. Also heard G and several times the OY6BEC beacon in IP62 as well as a LA beacon.




9cm DB6NT kit

Now i started soldering the 9cm transverter kit that was in the shelf since years. The filter caps look already a bit oxidated. But soldering still worked fine. The new 9cm will get into a box together with 13cm at some time.

9cm DB6NT MK2 transverter partly assembled


9cm transverter

G4DDK Iceni 70cm transverter

I assembled the Iceni 70cm transverter kit from G4DDK. Instead of the ADE-13 i used a ADE-751MH+. Sam was so kind and sponsored one of his mixer samples he used for testing. Unfortunately the manufacturer of the mixers uses different pinouts for almost every type. In this case i had to swap RF and IP ports. The good one: It is not difficult with the layout. In the picture you can see the short semirigid.

G4DDK Iceni transverter for 70cm

The next picture shows some IM3 measurement for the RX part of the transverter. The estimated input IM3 point is around 0dBm now (21dB gain).
The P1dB is about -9dBm (2x -12dBm).

Iceni ADE-751 IM3

I also checked the output signal. The 2nd harmonic is about 53dB below wanted signal and the LO suppression is about 58dB. So some extra filter might be required to the comply with regulations.
Overall i am very satisfied with this transverter block. With the alternative mixer the performance is even better than it was before.
Next i need to add a amplifier and other unimportant things like sequencer, RX/TX-switch, chassis and so on ;)

6cm PA chain

For my 6cm transverter i bought a 10W DL2AM PA years ago. Because it needs about 1W drive i combine it with the WLAN PA from here
6cm PA chain
The complete chain now has about 39dB gain and a P1dB of about 40dBm. So its working fine.

6cm PA chain output power

The current consumption for the both PA separately (orange driver current in mA, blue PA current in A).

6cm PA current consumption

A small VHF/UHF driver

I was searching for a small driver for 2m in order to have enough power for my microwave transverters. I usually drive them with about 500mW. Since i have a transverter block with about 0dBm output it needs some gain. Again i found something from China. The advertisement told something about 1.5W, the pictures showed a PCB with a print 35dB/3.2W. However, i thought it could be good enough to get 0.5W out of it.

A small VHF/UHF amplifier

When the device arrived i noticed that the manufacturer milled the top of the two amplifier IC. Very funny that the guys there try to save their designs from unwanted copy ;)
At the input there is a 6dB attenuation pad which are followed by two amplifier stages of unknown type. The first stage is supplied via a 5V regulator, the second one is connected to the supply input directly. I used 12V to do some measurements.
The first action was to know the gain of the circuit. I wanted to see if it is really working from 1 to 700MHz.
In the picture you see the little noisy measurement. The drive from the analyzer was set very low.

Gain of small VHF/UHF PA

From the gain curve it can be seen that the device is probably not working that well at the lowest end of the shortwave. But at least from 30MHz on it should be usable. Towards upper frequencies the gain is decreasing a lot but still 27dB at 700MHz. For the 2m band roughly 43dB gain is achieved and about 33dB in the 70cm band.
Finally i wanted to know which output power can be achieved in the amateur radio bands.

VHF/UHF PA output power

At about 1W output the output always gets compressed. You might add about 0.4dB on 70cm and 0.3dB on 2m to my measurements since the graph does not include the attenuation of the output cable. For me it means that the amplifier should work well for my purpose.

A simple 9cm monitoring receiver

Just for fun i tried to collect some components from the shelf and plugged together a simple monitoring receiver for 9cm.
I have a DF9NP PLL OCXO for 2592.2MHz and a pipe-cap filter tuned to 3400MHz. From China i ordered a wideband LNA some month ago. It has about 15dB gain on 9cm. The mixer is a ZEM-4300+ (+7dBm LO). The setup results in a IF of 807.8MHz which is received with an RTLSDR and the very nice GQRX software.
With a short wire attached to the input of the LNA i was able to receive the local 9cm beacon DM0TUD.

9cm monitor hardware

GQRX receiving DM0TUD 9cm beacon

Finally a 6cm horn antenna

In this post [Link] i wrote about a 6cm horn for offset dishes from Russia. The horn was designed for 5720MHz and i was not able to tune it to 5760MHz were i wanted to use it. DG2DWL gave it another try and added a M6 tuning screw opposite to the feed tip. He managed to get the resonance to the correct frequency.
So with some modification these horns are a good alternative for offset dishes in the 6cm narrow band section.

russian 6cm horn tuned to 5760MHz

Searching for some FreeDV QSO partner on VHF

Since i use Quisk for my HiQSDR i found it interesting to experiment with FreeDV again. Quisk can directly support using the FreeDV API and work in this digital mode without building lots of cables. Since i wanted to try the latest mode 700C i had to compile the library from the scratch and add the mode to the configuration of quisk. Below you can find recordings of my CQ call in the modes 1600 and 700C which were made loopback.
Now i search for a QSO partner preferably on 2m somewhere in the area around JO61. I can work relatively well direction southeast. So east OK might be good.

Mode 1600

Mode 700C

Please remember the 700C mode uses only 1kHz of bandwidth.
If you are interested in some tests just send me a email to