QO-100 at CN3A

Together with Vasek OK1VVT during CQ WW SSB 2024 on CN3A we talked and thought about what could be done on VHF. Besides future plans with 2m EME I thought about the QO-100 satellite. Since I have been building LNBs for several years, not only for this satellite, it was "just" enough to finish the rest :)

For several years I have been using an Adalm pluto SDR TRX with additional front end boards for VHF remote control (70 MHz, 144 MHz, 433 MHz). So I decided to use this SDR together with a great SDR program - SDR Console. For the RX I used my LNB ext OSC - that is an LNB with the ability to hang a PLL using an external 10 MHz normal. This GPSDO also serves as a reference signal source for the Adalm Pluto. I also found a nice 10W PA in China. I just had to add some more parts like LAN and PoE filters, DC-DC converter with filters and mount it in a box with a heat sink. 

I printed an ice cone feed as an antenna. Outdoor box is connected only with one CAT-5 FTP cable. There is common power supply with LAN filter and PoE injector - all in one enclosure.

LNB: LNB ext OSC MK3

Adalm Pluto: with EXT REF

LAN and PoE filter: with protections LAN PRO-FIL

ICE CONE FEED: web of author

Common 24V power supply with filters

GPSDO board with LNB bias tee, Adalm Pluto PA and DC converters

Testing output power

First test at CN3A without the dish

v

The first test on CN3A was done without dish antenna in January 2025. Despite the opposite polarization of the transmitting antenna and simple support of the antenna on an improvised table, it was possible to listen to the beacon. After tuning to the FT8 frequency, I was surprised that I easily decoded several stations. I tried transmitting with 6W RF power into the wrong polarization and it worked :) The first QSO was very easy and thanks to Libor OK1ALX for the test! After the first CQ an avalanche of calling stations came down.

After a month it was time to go again for 14 days of working relaxation on CN3A. Apart from work and CQ WPX SSB I planned to finish the equipment for QO-100, buy a dish and holder and mount everything.

After a couple of days, Jirka OK1RI and I went to get some food and drink supplies and also visited the local “hardware” street in Safi. After an exchange of greetings and a commented (in Czech) demonstration of photos of the antenna on a mobile phone, the seller brought us the antenna and the wall mount. Even a first year engineering student would be ashamed of this mount... but better than nothing :)

After installing and pointing the antenna, the increase in signal strength was significant. The gain was around 30 dB and our own signal is at S9 level. When there is more time, we will sit down to SSB, where it will be much more fun compare to FT8...

All QSOs are confirmed over LOTW.

 2m Es 3.6. 2024 (remote from SV2 holiday)

Yesterday, as part of our holiday in Greece, we visited the ruins of the ancient city of Olynthus. This monument reveals the remains of a city more than 3,000 years old. It's unbelievable that even back then they were able to build a 13km long water pipe to feed the fountain :) Today it would not be possible without the supermarket - development of society :) And it is also the development that can't be stopped - in a few moments I could see the remote desktop of my PC on my remote QTH. Something told me to connect and have a look and I couldn't stop wondering - CQ OD5VB. Beautiful signal, QSOs would be possible on SSB, but I'm not equipped for that. So at least FT8. The contact is made in a minute. Ant OD5VB disappears again in the noise. The distance is a nice 2450 km. Interestingly, after a while Pavel OK1ADT from the nearby QTH in Pardubice makes contact, but there is complete silence on the band for me.

After a while 4X/OM2IB and 4X1GA appear. Both only in one period.

First 2m Es in 2024 2.6. (remote from SV2 holiday)

After long months, the long awaited Es on 144MHz arrived. We are spending our holidays in Thessaloniki SV2 at the QTH of Ondra OK1CDJ, where I am active with little HF equipment. In the morning of the 2.6. 2024 I was in QSO with Pavel OK1ADT and we were discussing sadly about bad CONDX, when suddenly I saw CQ UA1ASA KO48 on 2m. Contact was made in a minute. In the meantime I watched 4m and the band opened up nicely to the north.

There is hope for Es on 2m as well. In the afternoon we drive to the centre of Thessaloniki and I forget to charge my mobile phone. I try the remote desktop to my OL7M remote site and the band is full of EA stations! I try to call one and it works. But the phone is dead, so I only manage to call a couple of stations - I'm not using AUTO! I still manage a couple of EAs and IS0. The Es took a surprisingly long time. I still hear some stations even after returning from the city. 

I also managed to find a lot of new stations on 4m. 

144MHz RIG: Adalm Pluto + 2m front-end + 70W PA + 12el G0KSC @ 15m

QTH: OL7M JO80CF

2m QSO 3.6. 2024

2m PSK reporter 2.6. 2024

4m PSK reporter 2.6. 2024

4m QSO 3.6. 2024

RX AUDITE VHF - version for 6 and 4m

This is new version of RX Audite. Redesigned for 50 and 70MHz, including filters, LNA with PGA-103+ and rest protections and switching as in the classic one.

You can find more at our web: https://hamparts.shop/rx-audite-vhf.html

This is the ideal solution for monitoring both 6 and 4m bands using one dual band Yagi antenna. However, you can also use it on one band and monitor, for example, both FT8 bands (50,313 and 50,323), or monitor the analog segment (beacons) and the FT8 one at the same time. This allows better monitoring of propagation conditions. RX AUDITE VHF also includes LNA and bandpass filters to limit signals from HF and FM BC transmitters.

Application:

- 6 and/or 4m RX splitter

- Monitoring both FT8 segments at 6m

- Dual band antenna splitter to 6 and 4m

- Web SDR and skimmer

- RX protections

- Low Noise Preamp and filters

 Nice Es openning 15th June 2023

There were very nice Es openning at 4 and 2 meters. Made my new ODX at 2m FT8 with  Stefan CT9/OM3RG at distance 3365 km to IM12.