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.

LZ5HP_13cm

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).

Nov 01 2015

Tropo on VHF

No. The map below is not the map with the route asilum seekers are taking from Syria towards rich country in Western Europe. It’s a real-time map showing tropo ducts on VHF. This data is bases on APRS stations transmitting there GPS-position on 144.800 MHz. You should save it on your bookmarks is active on VHF and UHF! The URL: aprs.mountainlake.k12.mn.us.

Tropo

Oct 29 2015

Switching to vertical: First results

cg3000A few months back I switched from a magnetic loop antenna to a vertical one. There were two main reasons to do so. The first one is the ability to be able to remotely tune the antenna. With the I3VHF-loop I wasn’t able to. The second reason was to have support for the 80 (and soon to be released) 60-meter band. If 160 would work this would be a great benefit.
Using a 12-meter high SpiderBeam fiber pole, without the last section, a wire goes 10,5 meters up and 3,5 meters to the side, with a total length of 14 meters. This length is chosen because the wire was already in stock and isn’t resonating on any of the ham bands. The CG-3000 tuner will tune the wire to all bands, including 160-meters. But the topband isn’t really workable with S9 noise.

Last week I made about 200 QSO’s during the CQ-WW-DX SSB-contest to test the antenna. Lower bands in particular perform much, much better with the new set-up comparing to the I3VHF loop. On the 40-meter band, local QSO’s are quite impossible (No more ‘noise’ from 7077 kHz a.k.a. ‘CB channel 14’ in the Netherlands) and distances 1000 miles away are better. I’ve worked D4C in Cape Verde, Kuwait, a US West coast stations, Canada and Barbados in the Caribbean.

Last week I had some time to do tests in JT65 on the 80-meter band. I hoped to get outside of Europe on this band, but did not expect to have QSO’s with the US and Canada (6.000 km) and Australia (18.000 km). The original goal is still set: 100 DXCC on both 160 and 80 (maybe even 60) meters together before the end of this year. To achieve that, I have to run a night during next month’s CQ-WW-DX CW-contest.

Sep 15 2015

Playing with the DV4mini

The last post has been a while now. I was busy preparing the annual Balloonfoxhunt and helping Mischa (PA1OKZ) out with expanding the PI2NOS repeater system. Last week a package arrived from Hamshop, the distributor for the DV4mini USB stick in the Netherlands and Belgium. Time to start playing around…

What is the DV4mini

The DV4mini is an micro transceiver for several digimodes. In it’s current version, D-Star, DMR and System Fusion are supported. The developers are working on support for ACPO P25 in the next v1.6 version but since P25 isn’t widely used throughout Europe and I don’t have the gear to test it, no reason to test the released v1.6 beta-software. The latest supported production version is version 1.4 available here. The USB stick should have build in drivers for Windows 7 and upwards. The radio has 10 milliWatts of output power and works on UHF only.

Let’s plug it in – Windows 7 (64-bit)

According the manual, drivers for Windows 7 will be automatically installed. Unfortunately for me that was not the case. And since drivers for Windows 7 (x64) are not available as download, I had to use the XP version and ignore some errors forcing the driver to install. And yes, the Visual Studio 2013 runtime was installed as 32 bit version before… After installing the driver, the program would start up and recognise the stick.

Testing D-Star

Not tested, yet

Testing DMR

To start this test, first thing I have to mention is that the USB stick transmits on TimeSlot 2, Group 9, simplex only. So be sure to program your terminal according. I tested with the Hytera PD785G portable radio. Second thing to say is that the WorldWide (TS1-1) and domestic (TS1-204) network are not supported (yet). At this moment, only the DMRplus reflectors are supported. This had to do with the DMR backbone infrastructure where every country runs his own master server(s). You do not want every ham to connect to this network. That would bring instability to the repeaters throughout the country. Maybe later on, the Dutch DMR-master administrator is setting up a 2nd master server dedicated for DV4mini users. He’s more than willing to, but it needs to be supported by the DV4mini software to.

Testing System Fusion

Unfortunately I don’t own any Yaesu equipment supporting the C4FM System Fusion protocol. I might borrow some from one of the fellow hams at the local club to do some tests later on…

Apr 29 2015

Half way DXCC-Challenge

Today I noticed I’m half way the DXCC-challenge with 500 band-points. Now that I have access to the 80-meter and (limited) 160-meter band, I hope to achieve 50 band-points on these together before next year. Meanwhile, a worked-indicator in the Logbook shows me new countries per band. I’m still very limited with my antenne set-up (Magnetic Loop before, now Inverted-L) but it’s called the DXCC-Challenge so let the challenge come. 🙂

Meanwhile I continue to build my portable VHF – UHF set-up to be more active on 2-meter, 70-centimeter and 23-centimeters, be it a semi-portable operation from the car on top of a hill (location still to be scouted) during the bigger contests in Europe. Not much band-points to get over here, neither easy band-points but very challenging it is!

Screen Shot 2015-04-29 at 10.33.08

Apr 20 2015

Building Inverted-L

I’m busy building an inverted L antenna. Going about 10 meters up and 10 meters horizontal. This gives me the possibility to work on the 80-meter and 160-meter band, using a CG-3000 tuner. I’m currently using about 2x 12 meters of wire as counterpose. This will be a bit more in the near future, but yesterday I wanted to finish quickly. First QSO’s in CW and JT65 are made on 160-meters and 80-meters.

My first QSO on the 160-meter band. Confirmed via eQSL and LoTW.

My first on the 160M band. Confirmed via eQSL and LoTW.

No more tuning every 3 kHz like I had to do with the Magnetic Loops in the past. I’ll test this setup for some weeks and compare it – in particular receiving part – with the I3VHF Magnetic Loop to see how this is picking up noise from the environment I live in.

 cg3000inv-l-boom

Apr 13 2015

MLA-T from the inside

Some pictures from the MLA-T Magnetic Loop Antenna. You can see the stepper motor (with 1:600 delay), the feedlines from the N (Yes, N, not PL) connectors and the extension capacitor with shunt for operations on the 160-meter band.

IMG_2414IMG_2413

IMG_2412

Apr 11 2015

New antenna for PI6ATS

IMG_0491PI6ATS, a locat ATV repeater, has a new VHF-antenne. The operators used an old indoor horizontal loop / halo antenna for audio reception on 144.7625 MHz.

This wasn’t the best situation, since many people had a way stronger signal on 13cm then on VHF, if the repeater could receive a signal (1750 HZ tone) at all.

Next: HAMNET antenne beaming towards the PI2NOS tower in Hilversum so that there is internet for streaming (out or maybe even in) and/or a web-controlled audio- and video switch?

Good to see my old antenne is recycled and has a new life. I’d suggest all ham radio operators to think about their local repeaters by donating hardware or some money to keep things running.

Thanks operators, for keeping PI6ATS in/on the air.

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