VK5ZD Home Page

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Hello and welcome to my web site.

I obtained my AOLCP and first licence (VK5ZIJ) back in August 1969.  Since then, various things have interrupted the hobby (marriage, work, kids, etc.) with the result that there have been rather large gaps in my activity. Currently, my main interest lies in experimenting with equipment for the microwave bands (1296MHz - 24GHz).  I have constructed transverters for 23cm, 13cm, 9cm, 6cm and 3cm.


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Page Last Updated: 9 April 2010    124211 Visitors since 03 October 2009

11 Nov 2011I've completed my 24GHz transverter which is based on a 23GHz Thales unit purchased on eBay. Preliminary test indicate that it's working, but I'll be conducting a long range test this coming Sunday. I don't have a suitable antenna switching device so I just built two antennas (25db gain horns).
16 Oct 2011My DB6NT 10GHz transverter has been updated with the addition of a 3W PA that I've had lying around for a couple of years. Thought it's about time I made use of it. The electronics have also been moved to the rear of the dish and I'm using WR75 waveguide up to the feed.
08 Aug 2011I've done a re-build of my first 1296MHz transverter and added an 80W PA stage. This also required a new power supply (the PA needs 24v at 8A) which is in the box below the transverter.
19 Jun 2011I've just completed a weekend of contesting in the WIA winter VHF/UHF field day. Saturday was cold and wet and I spent almost as much time waiting for rain to pass as I did operating.
07 Jun 2011I recently aquired a 900mm dish prime focus courtesy of Darryl, Vk5HZ. The dish came with a feed for 5.7GHz which, according to the label, was originally designed for use in a grid antenna. Since I already have two dishes for 5.7GHz (60cm and 1.2m) I decided to use this dish for 1.3GHz, 2.4Ghz and 3.4GHz (the 5.7GHz feed was fitted to a spare grid antenna I had and it works well with ~28dbi gain). For 1.3GHz I made a 3 element yagi feed while for 2.4GHz and 3.4GHz I used a traditional 'coffee can' feed (actually licorice allsorts and chocolate coated nuts cans). A length a 20mm PVC water pipe was fitted to the feed point and the antennas were fitted to PVC joining sleeves that can slide over this pipe.
21 May 2011Added a PA stage to one of my 3.4GHz transverters. The output level is now 4 watts (previously ~40mW).
30 Apr 2011Rx fault in my VK3XDK 10GHz transverter has been found and fixed. Conducted some more tests and everything works fine. The receiver seems quite sensitive now.
23 Apr 2011First test of my VK3ZDK 10GHz transverter. Tx works fine but the receiver is seriously deaf!
19 Mar 2011Took part in my local radio club's effort for the John Moyle Field Day. The main effort was on HF but I also took the microwave gear to provide some contacts for other local stations.
14 Mar 2011Succeeded in setting two new VK microwave records today for mobile contacts. 144.9km on 5.7GHz and 165.4km on 10GHz. In the picture the 5.7GHz horn is on the right and the 10GHz one is at the top. The larger horn on the left is for 3.4GHz. I need to try a bit harder to beat the current mobile record (170.1km) on that band.
17 Jan 2011Went to Yorke Peninsula for the summer VHF/UHF field day. Tried my 1.2m dish for the first time on 5.7GHz. Made contacts on all bands up to 10GHz.
10 Dec 2010Did some short range (about 30km) tests on 3.4GHz and 5.7GHz with Keith, VK5OQ. I had two transverters for each band. Everything worked as expected, including the fact that one of my 5.7GHz transverters is still deaf. I recently did some 'snowflaking' on the LO multiplier which significantly increased the LO drive to the mixers. This increased the audible mixer noise in the I.F. transceiver but did nothing to improve the sensitivity. I now suspect the MMIC in the first RF stage has died.
25 Nov 2010Almost two years ago I bought surplus 'ioLink 1' RF unit. This is part of a system that provides a full duplex wireless data link. The device is designed to operate on one a three fixed frequency pairs around 5.8GHz. The original unit has three external coaxial connectors; (1) transmit IF input & DC power, (2) receive IF output and RSSI and (3) 5.8GHz antenna. The transmit and receive frequencies are 60MHz apart and the device includes a diplexer for full duplex operation. The transmit IF frequency 110Mhz which is mixed with the LO signal to produce the transmit output frequency. The same LO signal is mixed with the receive input frequency to produce an IF of 170MHz. This is then mixed with a second LO on 240MHz to produce a second IF of 70MHz. Separate VCOs are used to generate the LO signals each with its own PLL referenced to a common 10MHz TCXO. This picture shows the PCB before modifications.

The ioLink unit has now been modified to be a 5.7GHz transverter. A Picaxe was added to program the PLL for the required LO frequency and handle the T/R switching. The receiver side is left running all the time but a relay was added to switch the power to the PA device. The diplexer was removed and replaced with an antenna changeover relay. On the receive side, the 170MHz and 70MHz filters, the second mixer, the second LO and three of the MMICs from the IF stages were removed and replaced with a simple 144MHz filter. The net result is a 5.7GHz transverter with about +29dbm transmiter output for an outlay of under $100. This picture shows the modified PCB.
25 Nov 2010Here is a picture of 3.4GHz transverter #2. It still need a PA as the transmit output power is only about 20mW.
23 Nov 2010As mentioned previously, I recently aquired a 1.2m dish and tripod. Since then I've added an equipment platform and a short mast to hold the 10GHz offset dish. I now need to add a sighting system so that it can be accurately pointed to a given bearing. In time I also intend to make feeds for 1.2GHz, 2.4GHz and 3.4GHz (not 10GHz because it will probably be too hard to aim).

Inside the Comet CHA-250BX
Notes on the Comet CHA-250BX
Measurements on the CHA-250BX
Pager Filter
Notes on the Unadilla W2AU Balun
Microwave Transverter
Other Microwave Stuff
Notes on the DB6NT 10GHz Transverter Kit
Microwave Antennas
Old Microwave Stuff
Links to other sites:
Wireless Institute of Australia
Elizabeth Amateur Radio Club
Adelaide Hills Amateur Radio Society
VK Classifieds
eHam Reviews
ACMA Licence Register