BRAND NEW WAVEGUIDE SWITCHES FOR 24GHz and 47GHZ NOW AVAILABLE AT LOW COST!
(Posted 22 February 2004)
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These WR28(WG22)switches are available from the WELLINGTON VHF GROUP, PO Box 12 259, Thorndon, Wellington, New Zealand. They are very suitable for 24GHz and 47GHz!
Email Leon Toorenberg, ZL2AOC at: leon@surveylab.co.nz He will give you a quote on price. When we bought a number of these switches a couple of months ago the price was $50 New Zealand plus postage to the UK. It worked out at around £23 (UK pounds Sterling), including post, for one unit. That's around $47 US ... a fantastic bargain!Leon has a UK bank account as well as his usual NZ one. We arranged to pay into the UK account and so avoid any bank charges, etc. Those of you outside the UK may need to enquire at your bank about transfer of funds or merely send Leon US dollars. Check with him first to get an updated quote.In January 2004, Leon told me he had LOTS OF THESE BRAND NEW SWITCHES FOR SALE! HERE ARE THE MANUFACTURER'S SPECIFICATIONS FOR THE SWITCH FREQUENCY: 26.5-40GHz (IGNORE! THEY WORK FINE ON 24 AND 47GHz!) INSERTION LOSS: 0.25dB Maximum ISOLATION: 50dB minimum CONNECTORS: WR28 (UK WG22) The webmaster, G3PHO, has used WR28 and WR42 bolted together for years and the losses are almost unmeasureable so don't be afraid to use WR28 on 24GHz. Matching screws placed in the waveguide broad face, near the switch ports, may help to get a better match in some cases.If you are using a PA in your system you are strongly advised to use a SEQUENCE CHANGE OVER protocol if you want to keep your 24GHz receive preamp in good shape! They are easily made but you can buy them ready made at Kuhne Electronics (DB6NT) for little more than what it would cost you to make, assuming you had to source each component from new. |
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At long last a plentiful supply of LOW DC VOLTAGE, ELECTRICALLY OPERATED waveguide switches for both 24GHz and 47GHz has found its way to the amateur surplus market. Pictured above is the RelComm Techology model RDW SR002 three port waveguide switch. It's in WR28(which is the same as the British WG22). I have been using a MANUAL WR28 four port switch for several years and have had no problems using it with WR42 (WG20) butt-jointed directly against it. All that's needed is, with a needle file, to carefully elongate two diagonally opposite holes on the WR42 flanges so that screws can be fitted through the flange into the threads on the waveguide switch. The RelComm switch is electrically operated by means of a short pulse of 8.2V DC. In practice this means if you are running from a +12V portable supply you'll need to drop the supply by means of a 1 amp regulator to around 8 or 9 volts. A 3 pin 7808 or 7809 will do the trick.The six pin connector shown here has multicoloured wires coming from it. Changeover switching connections are as follows:(Thanks to WA1ZMS for these revised and corrected connections)
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