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ON5KQ Belgium flag Belgium

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June 2017

You can connect to my new Web-receiver via this URL:           http://on5kq.ddns.net:8073

The antenna is a horizontal Loop system based on the pre-amp from Chavdar, LZ1AQ. The antenna is unique, as it is omni-directional with purely horizontal polarization from 500kHz to 50Mhz. Combining two loops in parallel, reduces loop inductance to half and increase antenna area to double. Using Chavdar's pre-amp AAA-1C with very low impedance the antenna becomes a very broadband design - ideal for todays SDR-rx.

As all horizontal antenna's this antenna needs height to really make advantage of ground gain. The efficiency of the antenna becomes lower towards lower frequencies. But the loops work well from 1.8Mhz to 50Mhz - above 10Mhz there is considerable gain (6.5dbi to over 8dbi at 30Mhz). Especially for  MW/LW region I can switch the system from loop mode to dipole mode. In dipole mode each loop element is represents one half of a (thick) dipole. Although the antenne in dipole mode becomes directional (best sensitivity to east and west, -15db down to North/South), the dipole mode offers much better reception below 1Mhz and even as low as 10kHz (VLF)

You can see, when dipole mode is set on the web-rx: In that case there is a red banner on the opening picture of the web-rx, when you arrive via the Internet on the web-rx Interface...

The web-rx hardware is a kiwi-SDR developed by John, ZL/KF6VO

John developed the software for his Kiwi-SDR hardware based on the work of Andras Retzler, who developed OpenWebRx, an open-source software to offer Web-Access to SDR-receivers (for details look here: http://sdr.hu/openwebrx

Spring 2017

Experimental additional CW-skimmer with callsign on5kq-1 installed. Antenna for the summer is now a horizontal magnetic loop system of 2x 1.6m diameter, made of 20mm Alu-tube material with LZ1AQ pre-amp. This antenna is omni-directional. First test with 3.5m height later at final height of 11m on a small tower. Antenna works very nicely from 1.8 - 50Mhz continiously... Before the coming and usually stormy winter season, I need to mount the system much more rugged but keep weight to minimum.... so more work to be done..

Receiver for ON5KQ-1 is Elad FDM S2 (so only 2x 192kHz skimming at a time)

16th of March 2017 - Winter season ended!

Today I had to take done the remaining 195m Beverage to East, because the field needs to be prepared and there need to be room for the tractor... Winter radio season has ended. But many new ideas are born with exeriments I did during the winter. Over the summer I will prepare the ideas to working products to be used next season for even better reception (WSPR, CW-skimmer, Web-Radio, etc...)

Remaining antennas over the summer will be various verticals and longwires... mostly fieldday style...

The remote rx will be operational as well as the ON5KQ  cw-skimmer on the remote place as can be seen on the picture above (from under the windmills...)

Mid March 2017:

Doing a few tests in WSPR mode before closing of the winter season... Instead of ON5KQ-1 using the Beverages for CW-skimmer (in my home location jo10os), I use them for some tests in WSPR for very weak signal reception. It is amazing, what the decoder WSJT-X together with my ELAD SW2 can pick-up on 80/40m.

Using a temporary short 60m wire at 1m hight to the west from 22h utc to 8 utc and a 195m Beverage to east from 8-22h utc...

Update January 2017:

I setup a secondary skimmer at my home location jo10os = ON5KQ-1

This skimmer is to compare the results on the lowbands with my remote location in jo11of using a simple loop antenna following and using advice and pre-amp from LZ1AQ. The remote CW-skimmer call is ON5KQ (see foto above)

For the temp. CW-skimmer with ON5KQ-1, I am using a 195m long Beverage ant very similar than the Japan Beverage (see the foto below), but slightly different direction to 70deg. To keep it simple I do not use any resistor at the end of the wire, but keep it bi-directional. Antenna height is 1m - length = 195m, feeding with 1:4 impedance matching transformer to 75Ohm coax to the receiver.  RX is the Elad FDM-SW2,  16bit digital SDR receiver, no additional pre-amp is used.

From time to time I use ON5KQ-1 in addition to the normal remote CW-skimmer for comparisons...

December 2016:

This coming winter season, there will be no Beverage beam antennas for the lowbands. It was just too much work necessary to setup my CW-Skimmer plus the new Web-Rx at the new location about 60km north from here close to the Belgian NorthSea coast.

I am using a special Loop antenna in the middle of a 2000m2 steel roof. 10-15years ago, this was my old contest place, which proofed very good ratiation in all directions. Today however, it has become a very busy industrial place plus a major powerplant for windpower and sunpower. Several 100000m2 sunpower-panels are installed in the very close neighborhood and many 4.5MW windpower turbines were build. The nearest windmill is only 90m from the antenna, which is only possible, because it is an industrial area - no residents are living there.

The reason, why I wanted to test this area was, that my home area (even very rural place with many space for long antennas) is more and more badly affected with big QRM from High Speed Internet Networks leakage (15db noiselevel increase was measured by the authoroties, but they said, that it must be tolerated....). Additionally almost all qrg's are suffering heavily from In-house broadband powerline communication. Cable TV-connections to homes are standard installed with PLC modems which makes installation work for the Telecoms very easy and cheap for them - so amateur radio is badly affected.

I thought, to test the industrial area at the coast, because there are no residents with PLC and also there are NO leaking networks (VDSL2 by Proximus) over old residential telephone lines...

During CQWW CW contest the CW-skimmer installation proofed to be not too bad. 

You can listen on the Web-Rx by connecting to this URL:

Any feedback on the reception quality of the Web-Rx is welcome.

Many thanks,  

Ulli, ON5KQ


update 29Febr.2016:

Winter season has ended! All Beverage antennas gone and waiting to be set-up again next winter... During the summer the CW-skimmer will only use my 2ele endfire Deltaloops to NW (USA) and another 2ele deltaloop beam to North East (Asia, Japan). The Deltaloop beams are broadband designs for rx only covering 160-40m. For the high bands a 5m long active vertical is used for the skimmer - very simple design compares with large beverage ant during the winter.

------------------------ old information - Beverages are only for winter season ! ---------------------

NO TX for the moment!

This winter season unfortunately I had no time to set-up my TX-station in time. Due to various unexpected failures with the automated switching network of my 8ele Vertical TX-array, repair is much more work, which I could not do on time. So I focussed on the CW-skimmer receiving system.

I use long beverages for receiving on all bands. Because on the high bands the sensitivity is very low, I use about 30db (!!) pre-amp on the high bands... (40-10m). On 160/80m 20db pre-amp is enough at the feedpoint of the Beverage antennas.

more than 600m cable was necessary to set-up all beverages very far from the next buildings and any electrical infrastructure. Even though, I could not yet find the noise source on 160 and partly 80m to the south east direction, which makes the 350m wire on 160/80m almost useless...

Please see pictures below...

CW-skimmer station:  QS1R receiver, completely new antenna set-up (see below)

update Nov 2015:

The winter set-up for the CW-skimmer is in place for about 1week now. Unfortunately I have a strong noise source on the 135deg Beverage ant, which has to be resolved before I can report real good S/N ratio on the Low bands.

Currently the following ant are used for the skimmer and swiched sometimes randomly, as I use the receiver also for short wave listening at the same time:

- single Beverage ant to 135deg, 350m terminated with 500Ohm

- single Beverage ant to 90deg, 180m, not terminated

- single Beverage ant to 45deg, 220m gently down sloping terrain towards 45deg, terminated with 500Ohm

- 2ele endfire array of elongated loops, 25m wire length per element, 1kOhm termination, 31m spacing, 180deg phasing to 315deg

- 2ele endfire array if elongated loops, 25m wire length per element, 1kOhm termination, 31m spacing, 180deg phasing to 45deg

All rx antennas are broadband ant for reception only.

I use very simple home-build W7IUV pre-amps and home-build power combiner, if necessary.

The TX-station is QRT for the moment - the 8ele vertical array for 40m TX is also out of order (needs complete refurbishing) and therefore is not used for the CW-skimmer

The different beverage antennas are using fields of 28ha in total (approx. 69acre), which I got permission to use over the winter, from my neighbor a local farmer... many thanks!

The antenna feed points are far away and at least 200m from any house... nevertheless our area still is very noisy, as overhead powercables are excellent antennes for broadband power-line communication, faulty or non-compliant LED drivers (most of them are not compliant!), etc.... noise levels are up 20db in the last 4-5 years....

But this is the best I can do !

Antenna to Japan, far east Asia(45deg from here):   (the trees down the small hill are 400-500m away - the trees on the left about 300m far away and up to 35m high)

The above view shows the gently sloping terrain toward Japan - this antenna is 220m long and sloping to 45deg (Japan, far east Asia)

The picture below shows the 350m (1150feet) Beverage to 135deg from here (east Africa, middle east, Indian Ocean, long pass W6/W7/VE7)

The trees in the far, are 800m away...

All antennas are only for reception.


8262713 Last modified: 2017-08-09 08:51:30, 11807 bytes

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