Feb 08 2012


I’m Randy, a 36-year old ham living in Amersfoort, which is located about 25 miles east from Amsterdam. Licensed since aged 17 in 1997 and active on all bands from 160 meters up till 3cm tough VHF, UHF and SHF are prefered in (SSB) voice, ATV and weak-signal modes.

On the day to day job I work as Technical Consultant specified in Infrastructure and Linux solutions.  I’m a board-member (secretary) of the VERON Public Relations Committee and the secretary of the VERON ICT Working Group. Also doing some hands-on support stuff for repeater group PI2NOS and PI3UTR and PA6ATV (Hobbyscoop)  and trying to promote HAMNET and DMR-activities with a group of ham’s throughout the country.

Oct 18 2016

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).


Aug 10 2016

Building an 13cm SSPA

With a few hams on the club we’re busy building 13cm SSPA’s. The base equipment is ex 3G/UMTS equipment. There are two models availlable for around 10 euro’s and can be found on ham flea markets. The small module has an output of about 30 Watts, the big modules output is around 90 Watts. on 2140 MHz. Both are usable on 2350 MHz. First, let’s have a look at the stages and modules used. Goal is to use the SSPA for the Es’HailSat 2 uplink. See PA3FYM’s website for details about antennas used for this project.


From left to right we have 2 modules on the 30 Watt SSPA, 3 on the 90 Watt SSPA. I’ll write down the details of the 90 Watt SSPA. The 30 Watt version is the same, but the last stage is missing. The input (left) is +5 dBm (3 mWatt) and is feeded into an MHL21336, the blue module. This has an amplification of 31 dB and is feeded into the second stage, an MRF21030S with an aplification of 13 dB. From here, it goes to the final stage to add 5 dB more gain using an SRF7068H5HS (MRF21085S?).

I’ve created an bypass in the first stage. The output of the LZ5HP transverter is about 2 Watts and, altough 1,5 dB to less, enough to feed the second stage. The alternative was to attenuate the TX-signal from the transverter with 30 dB from 2 Watts down to 1 mililWatt. Additional benefit is that the first stage (blue module) has an aplification of 31 dB wich will result in difficulties in the housing due to howling and crosstalk. By bypassing this module, that problem is solved the easy way.

All is powered by 28 Volts (DC) and still work in progress. To be continued.

Remco's (PE1PIP) result...

Remco’s (PE1PIP) result…

Aug 06 2016

Hytera MD785(G) noise modification

The Hytera MD785(G) DMR transceiver works great out of the box, both analogue as digital. But there is one problem. Noise coming out of the speaker. Even when the tansceivers audio gain botton is set to zero. When the squelch opens, noise can be heard. There is no way to fix this in the firmware of CPS codeplug by programming.

The modification is to put a 22 Ohm resistor in serie with the speaker. So, hardware needs to be mobified. The good news: The modification is easy and no SMD needs to be soldered. Just remove the front of the MD785, carefully remove the flatcable and put a 22 Ohm (variable) resister in series with the red speakerwire. That’s all.

Now reprogram you radio and set the speaker output level for both analog and digital by +2 or +3 db as compensation for the resistor you’ve just placed. Upload the codeplug and you’re done. The noise is gone.

Step 1: remove the front and *carefullly* remove the flatcable if you need more space.

Step 1: remove the front and *carefullly* remove the flatcable if you need more space.

Step 2: Put a 220 Ohm (variable) resistor in serie with the red speaker wire.

Step 2: Put a 22 Ohm (variable) resistor in serie with the red speaker wire. Adjust the resistor if you feel the need to do so by a few Ohm.

Jul 14 2016

Welcome 13cm band SSB

Since last month I’m QRV on 2302 MHz to, with help from the LZ5HP transverter. Next is to build an SSPA based on ex 3G/UMTS equipment. The modules and 24VDC PSU is there. I only need to find the right heatsink.


Jun 29 2016

Bluestack and BlueDV: Hotspot in a box

Developments for DMR and D-Star hotspots go fast. I already owned a UHF hotspot from PE1PLM which fits on top of the Raspberry Pi. With custom firmware, this also works with MMDVM software thus DMR. A new toy is the BlueStack, developed by PE1MSZ and sold via CombiTronics.nl.

Put the DVMEGA (UHF) transmitter on top of the BlueStack, install BlueDV on your Android phone and the unit connects via BlueTooth to your phone and from there to the D-Star and DMR networks. I don’t have to tell you that a USB power pack will give you a full portable hotspot. Nice for the car, on holidays or in the offices. Good work guys!

Update: To communicate via such a hotspot, a transceiver capable of the used DV mode is necessary to operate, the hotspot provides only an access gateway to the selected infrastructure. The hotspot has only one time slot. At the moment, the subscription on BrandMeister is dynamic and valid for 15 minutes.

A complete portable D-Star and DMR hotspot

A complete portable D-Star and DMR hotspot

Jun 29 2016

New house: Welcome back VHF UHF SHF

I’ve bought a new house and will be moving over end of september. The good news: It has a big, flat roof to put my VHF, UHF and SHF antennas on top of it. The other good news: The 3 story high building itself is about 9 meters in height, but it’s on top of a hill that also is about 11 metes heigh, overlooking the area which is a must-have to be succesvol on microwave bands. So the antennas will be on, lets say, 22 meters above street level.

A view to the north from the 2nd floor. Antennas will me +10 meter? You can see the city of Bunschoten Spakenburg.

A view to the north from the 2nd floor.

A view to the south from the 3rd floor. Antennas will be +5 meter? You can see the city of Amersfoort.

A view to the south from the 3rd floor.

I guess that means the end of HF for a while since I want to concentrate on the VHF and up bands. The gear is there to work on 6, 4 and 2-meters, 70, 23, 13 and 6 cm (and RX on 9 and 3cm). I have to build a transverter for the 9cm and 3cm band. Power is minimal, but RF-pallets and ex UMTS/3G network gear will do that for you. I’ve already collected 30 and 90 Watts 2140 MHz modules that can easily be converted to 2300 MHz.

Update: Moved over end of September. New panorama photo’s taken during a roof inspection.

west_to-east east-to-west

Jun 10 2016

Yeasu FT-817ND as IF transceiver

FT-817NDTo work more portable on UHF+ and SHF (and to have a nice transceiver to feed the LZ5HP 13cm transverter) I’ve bought an Yeasu FT-817nd at the Hamshop. Within two days, the 0.5PPM TXCO arrived from England via Ebay.

I bought tis unit because the IC-9100 isn’t a great transceiver to use with HF. As well as others, the IC-9100 had problems with RF spikes just miliseconds after pushing PTT. This can damage your transverter.

May 10 2016

Last minute VHF contest

Last weekend, VERON held her VHF-and-up contest together with other radio societies throughout Europe. Since I was bored anyway I’ve collected some stuff and wen’t portable for an hour and half. Things didn’t go smooth.

13199422_10207917748693853_1329898317_oI switched the 70cm and 23cm beam feeders, only noticing during break down. That’’s why 70cm didn’’t work at all and 23cm only worked domestic. On VHF (2m), my small 5-elements beam had a bad VSWR (1:3) so I was forced to work with 10 Watts QRP.

Still, I was able to learn and work some stations, including HB9 with minimum gear. Too bad there are only a very small number of active stations in PA on the higher frequencies. That group includes me due to antenna restrictions but since I’ve bought a new house and will move over September / October this year I’m able to get some antenna’s back on the roof and be active on 6/4/2/70/23/13 again.

Nov 30 2015

CQ-WW-DX CW contest 2015

CQ-WW-DX-CQ-sumThis weekend was CQ-WW-DX CW contest time. I spend some hours on the radio, in between other activities. My goal was to make about 100 QSO’s on each low band but I didn’t want to spend the night behind the rig. So the score is very low for the 160-meter band.

The 10-meter band was open but my antenna is to long for it. I did however work Australia, but an missing US and Canada (zone 2, 3, 4, 5) and the Caribian (zone 8 and 9). Due to heavy wind I wasn’t able to put up the Moxon antenne for 10. The results on 15-meters are okay, the 20-meter band had better times in the past.

Read the rest of this entry »

Nov 06 2015

1st during CQ-WW-DX SSB?

CQ-WW-DX_SSB_2015The raw scores from last months CQ-WW-DX SSB-contest are availlable. Tough I was operator at PI4AMF I also spend some hours making QSO’s from home. In total 200, QRP-assisted.

Seems to be enough to make it till the 1st place in the Netherlands if you rely on the RAW scores (search for PH4X).

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