October 2018 NAC contest on 144 MHz

50 QSO’s, 23 Locators, ODX 706km

September 2018 NAC contest on 432 MHz

25 QSO’s. 18 Locators. ODX: SK7MW (617km).


Peter (PA3PM) started to do some experiments with the ADALM SDR. This type of SDR is available for about $100 and capable of transmitting and receiving – even full-duplex – between 70 MHz and 6 GHz with a bandwidth up to 56 MHz. It’s capable to make DVB-S (and DVB-T) transmissions out of the box.

This week I’ve received my box. Within half an hour I was capable to produce an image on the PI6ATV repeater using the 1265 MHz DVB-S input and an old webcam. This is done with the native 0 dBm (1 milliWatt!) output of the SDR connected to my 120cm dish. I do have to note that there is a line of sight with the Gerbrandy tower more than 30 kilometers away.

Next is to amplify the signal using some RA18H1213G modules (18 Watt FM, 3 Watt DVB) on 23cm or some 3G modules still on stock for 13cm. And… more important, to filter the signals since the SDR will create harmonics.

B5 picture using 0 dBm over 30km+ distance

B5 picture using 0 dBm over 30km+ distance

Technical specs:

  • Separate RX and TX connector
  • 12 bits DAC/ADC
  • USB2 interface
  • 65.1 kSPS to 61.44 MSPS (200 kHz to 20 MHz signal bandwidth)
  • 325 to 4 GHz tuning range (70 MHz to 6 GHz after ‘mod’)
  • Runs Linux with an open design. 2 Second boot time.
  • 32 MB of Flash, 512 Mb of DDR3 memory
  • Only 72 parts on the board, thus cheap
  • Better RF than AD9363 specs
  • Highly linear broadband transmitter
    • Transmit (Tx) error vector magnitude (EVM): −34 dB
    • Tx noise: ≤−157 dBm/Hz noise floor
    • Tx monitor: 66 dB dynamic range with 1 dB accuracy
  • 2.4 Hz local oscillator (LO) step size
  • NO RF Shielding, NO RF Filtering. Use a low-pass filter!
  • Linux IIO interface: USB, Ethernet, Mass storage, Serial, DFU
  • Also capable to act as USB Host device
  • Very easy firmware update. Drag, drop and reboot. (and pray…)

September 2018 NAC contest on 144 MHz

Good activity. Made 57+ QSO’s in 4 hours. Tropo was okay. Not good, not bad. In total 25 locators. Up to now, the first place so far from all dutch participants, which is also the first time for me. But PA1T hasn’t upload his log and I’m sure I’ll be second afterwards. 🙂

September 2018 144 MHz contest

B-MULTI. Operators: PA3FYM and PH4X. ODX 840KM ,135 QSO’s. Problems with overheating SSPA, so running lower power.

August 2018 NAC contest on 1296 MHz

August 2018 NAC contest on 432 MHz

August 2018 NAC contest on 144 MHz

Lot’s of noise due to upcoming thunder storms. Therefor I had the idea that less stations from the UK were QRV tonight.

New amp coming in…

Today I’ve ordered a new SSPA amplifier. Now it’s for the 144 MHz band. I already bought a Gemini 180 Watt amp for 23cm in the past with the DXshop in the UK. After experiencing some issues with it, Roger (GW4WND) the owner of the shop, provided more than excellent service. And providing good service to customers pays off. The Gemini 2-500 is capable to deliver 500 Watts of power, so more than enough for the 400 Watt legal limit in the Netherlands. This new unit should line up perfectly with his brother on 23cm.

July 2018 NAC contest on 1296 MHz

Only 10 minutes in the shack before the doorbell rang and visitors arrived. No time to test-drive the new 120cm dish. Hope there will be some activity during the 1st weekend of August contest.

July 2018 NAC contest on 432 MHz

Terrible propagation. In the beginning of the evening I wasn’t even able to work OZ1BEF. Later, when temperatures were cooling down we’ve made a QSO. SK7MW is missing in the log to to the lack of tropo. In total I’ve made 20 QSO’s in about 2 hours (20.00-22.00 local time) with a total of 5637 km. ODX is OZ1BEF (510km). Total points: 11137, good for a second place (1st place in the LP10 section).

July 2018 contest results

I’ve worked hard the day before the contest to get the 120cm dish for 23/13cm mounted on the roof. Special thanks to Frans PC2F for helping me out. During the contest, the 144 MHz station was Multi-Op since Remco PA3FYM was coming over. He hasn’t been QRV on VHF for a while. I think the last time was PA6NL in 2016. Since he was logging on paper, I was busy on Sunday afternoon…

144 MHz results

432 MHz results


July 2018 NAC contest on 144 MHz

There were very good tropo openings towards LA and I was able to work multiple stations in JO59. Norway was a missing DXCC for me on 2-meters. I could even hear those stations on my FT-817 with rubber duck on the windowsill. Booming signals! After 2100 localtime I turned the antenna towards the UK. The desert of this contest was a QSO with GD0AMD/P from the Isle of Man. A complete new DXCC for me (didn’t work it on any band before). ODX today: LA2Z with 860 kilometers. In total I made 54 QSO’s. It could be a bit more but I had to stop before the end of the contest.

This maps shows tropo paths. Very good openings towards LA.

This maps shows tropo paths based on APRS data. Very good openings towards Norway (LA) and Denmark (OZ).

June 2018 NAC contest on 432 MHz

First NAC on 432 MHz this year. The 2nd Thuesday of the month is always difficult for me. In the log: Netherlands, Sweden, Denmark, Germany and England. ODX was SK7MW with 617km.

June 2018 NAC contest on 144 MHz

Todays NAC contest just finished. There were very good tropo conditions. Yesterday I could hear the OY beacon on both 144 and 432 MHz, today I didn’t (yet). But heard and worked many stations in GM and even a little bonus with stations in North Ireland. ODX: GM7PKT/P IO76NO 824 km with FT-817 and 5 Watts.

The other good thing: many active stations including many PA-stations. The amount of PD (Novice) stations participating is growing to every moth.

The map is too small :-)

The map is too small 🙂