23cm receiver PI6NOS

I’ve build an extra 23cm receiver for the regional 23cm repeater system PI6NOS in Hilversum. Building was quite straightforward. Just take a Raspberry Pi, an RTL-SDR stick and connect it to an antenna (using a band-pass filter not to overload the RTL-stick with crap).

The repeater system is based on an svxlink controller so just installing remotetrx on the RPi is enough to get started.  And since we’re hamradio operators and not internet amateurs, the remote receiver is connected via 5 GHz HAMNET. It even uses an indirect link from my house via the IJsselstein tower towards the Hilversum tower where the controller and transmitter is located.

There are still some improvements to be made and I have to mount a dedicated antenna for the system.  There is only one problem: when using my Alinco DJ-G5 triband portable on 23cm the signal, even with 100 mWatt, is blocking the receiver.

First price Belgium 144 MHz Spring contest

I won the first prize in the Belgium UBA spring contest on 144 MHz. within the QRP segment outside of Belgium. The caveat: I was the only one who send in a log :). Nevertheless I’d like to thank all Belgium stations for there patience working me. I was using about 5 Watts of power using a Ukrainian transverter behind the Icom IC-7300.

If I was sending in a regular log (no QRP) then I would have been second of the DX-stations. See you next year.

July 2017 NAC-contest 144 MHz

The first two hours I started beaming OZ and DL. Signals from OZ (and SM) where very loud. From 120 degrees (Germany Ruhrgebiet) I noticed local QRN. That’s why dots are missing in Germany. Later on I directed the beam 270 degrees towards the UK. Unfortunately no Wales or Scotland. The biggest surprise was a neighbour station a few hundred of meters away calling me. He said “Well. I guess this QSO doesn’t give you lots of points since we’re in the same locator”. Wrong! Each new locator (JO22) gives 500 bonus points. And since I didn’t work any other stations in JO22, this QSO gave almost the same points as a QSO with an OZ station in Denmark with a competitor in the same grid locator. So dutch hams. Build a Moxon (It will only costs you 15 minutes), put it on a broom and put it out of your attic window. Or take it with a FT-817 up a hill. You will work OZ, DL and G-stations and you will contribute to other competitors in the contest. Don’t have 144 MHz SSB? Visit PI4RCG. They have 2 base-stations for sale for 100 Euro each.

July 2017 VHF-UHF-SHF contest

New DXCC: SP (Poland) and EI (Ireland). The last one, I was able to work on 432 MHz in SSB and 144 Mhz in CW. Distance: 827km zo my ODX for this contest. I didn’t hear and work SM (Sweden) stations. I had a sked with an OE (Austria) station but unfortunately this didn’t work out. Maybe next time.

RSGB 144 MHz May contest 2017

Last weekend the RSGB held the annual 144 MHz May contest. I’ve made 17 QSO’s on Saturday. Just for fun. The log is send as checklog. I”ve made one mistake with G3WSK’s locator. UT1FG/MM was a surprise as operator, active from his boat on the Northsea. The band was quiet dead. ODX was M0WYB with 548 kilometers.

Preparing 23cm station

I’m preparing my 23cm station. Last weekend I’ve made some QSO’s during the May contest but with a very limited set-up. Time to have some more punch. Onboartd is a Gemini SSPA easily capable of delivering 180 Watts. More than enough for the 120 Watt limit here in the Netherlands for bands above 1 GHz. Also mountes is the SHF Elektrotechnik LNA capable of handling the same power. The todo is the antenna. I have to mount a 45-elements (5-elements reflector) 3,4 meters boom yagi for the 23cm band.

May 2017 VHF-UHF contest

Active on 144 and 432 MHz. New was 1296 MHz with a (very) limited set-up: 15-elements yagi (120cm boom) without pre-amp and 10 Watts of output power. Still able to work Belgium, Germany and England.

Antenna maintenance and QRV on 50/70 MHz

Last weekend I’ve performed some antenne maintenance. The LNA’s for 144 and 432 MHz are in place. I also mounted a small 15-elements antenna for 1296 MHz (23cm). During the contest last weekend I was able to make a QSO with Belgium, Germany and England with only 10 Watts of power and no LNA. I even heard a OK-station from the Czech Republic but due to lack of power I wasn’t able to work him.

For the Sporadic E season, a dual-band Moxon antenne is mounted for the 50 and 70 MHz bands. So with this set-up I’m able to work on 50, 70, 144, 432 and 1296 MHz and the HAMNET dish for 5600 MHz.

Special thanks goed to Gerton (PD0G) for helping me out. He was driving by for a cup of coffee while I was packing stuff to go to the roof.

N1MM+ and Icom IC-7300 Waterfall

The developers of N1MM+ software released a new build Amongst bugfixes there is one new feature to mention. Waterfall support for the Icom IC-7300. Read more on the N1MM Logger+ Facebook page or the documentation page on the website.

IC-7300 Spectrum display in N1MM+ version 1.0.6221Setup • Keep the noise level low by setting the ref level low and…

Geplaatst door N1MM Logger+ op dinsdag 25 april 2017

VHF and UHF preamps

Today the preamps for 144 and 432 MHz arrived from Wimo. They are manufactured by the German SHF-Elektronik and powered via the coax-line (My Icom IC-9100 supports 12 volt over coax). Both units have a VOX unit so no need for a seperate PTT-line (for now). Now I only have to find some time to mount them before the first weekend of may contest.


Last week we’ve reconnected the 220 meter high accesspoints in the Gerbrandy tower. Tough I’m not able to physically see the tower since it’s 31km away from my home (I can see the PI2NOS tower 16,3 km from my home) I accidentally discovered the Gerbrandy signal (PI1UTR) on HAMNET is 5 dB louder then the PI1NOS signal only halve the distance.

I turned the antenna permanent. The link looks stable with about 40 Mbit/sec bandwidth, using 5 dBm power in a 40cm dish (25 dBi gain), which makes 1 Watt EIRP in total. The ISM limit for outdoor Wifi in the Netherlands. This looks very promising since we’re busy rebuilding the PI6ATV repeater with output on 10 GHz.

I wrote an article in Dutch on HAMNET.nl.

March 2017 VHF-and-up contest

This weekend I found a few hours to participate in the IARU Region 1 March VHF-and-up contest. I started late on Saturday due to work for HAMNET and PI6ATV in the IJsseltein Tower but managed to run for about two hours. On Sunday late in the morning I found another few hours to contest. In total I’ve made 37 QSO’s on 144 and 432 MHz using low power without pre-amps. Best DX on 144 MHz: OK7O (606km) Best DX on 432 MHz: DL0HTW (573 km).

New rotatable tower

Today I’ve made some progress by replacing the antenna tower on the roof. It’s now rotatable. The Diamond X6000 has been replaced for the X5000 so the total length doesn’t exceed the 5 meter due to regulations to keep it license free without the need for a building permit. The 9-element LFA for 144 MHz and the 19-element LFA for 432 MHz are installed. The 120 cm dish for 1296 and 2320 MHz is on the todo list after there is some more counterweight placed.

Special thanks to Remco (PA3FYM) for helping me out.



Thanks PA3FYM for helping me out.

Thanks PA3FYM for helping me out.


The HAMNET connection is live. It’s not VPN based, but radio based on 5 GHz. I’m using an Ubiquiti Nanobeam M5-400 with 40cm dish to have enough gain towards the TV tower located about 16km from my home. Line of Sight is (just) availlable which is mandatory for a 5 GHz connection.

The dish needs to be moved up a meter or so since the flat roof is in the fresnel zone. Horizontal signal is about -85 dBm, vertikal about -81 dBm. Since I’m using cross polarity, +3 dB can be added making the total signal received about -80 dBm. Enough for 19,5/19,5 Mbit/sec with 10 MHz bandwitdh. The goal is about -75 dBm signal.

ATV station for 5700 MHz (6cm)

The new ATV station for 6cm consists of:

  • 23cm UniTX transmitter for 1400 MHz uplink
  • DG0VE Frequency multiplier
  • DG0VE amplifier: 60 mWatt > 600 mWatt
  • Final amplifier: 150 mWatt > 14 Watt
  • SMA coax relay to switch between TX and RX
  • RX converter 5,7 -> 1,0 GHz with pre-amp
  • Some sensors for temperature, fan control, etc

The complete set-up (excl. antenna) is mounted in an outdoor enclosure. Any 75Ω satellite coax can be used as transmission line since losses are low due to the 1400 MHz uplink and 1000 MHz downlink. These frequencies are outside of the 23cm band so there shouldn’t be any interference. For the last 2 meters between outdoor unit and antenne, Aircom Plus is being used with a length of about 3 meters. The unit is powered by 12 Volts and 4 cables to control the unit are going down. Any decent outdoor UTP (STP) cable is sufficient for this.

I’m able to receive om 23, 13, 9, 6 and 3cm and transmit on 23cm (low power) and 6cm (medium power).