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Spring 2004 Issue |
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MICROWAVES Surplus
Components to Construct By Chuck Houghton,* WB6IGP |
My 1296 transverter for our microwave group’s 1296 rig show and tell. The power supply and synthesizer are located under the main chassis frame. Photo shows bottom left: the mixer, bi-directional 1296 IF strip just above the mixer (gold-color PC board), relay for DC switching, and SMA coaxial relay. Top center is the 1240- to 1300-MHz filter, the preamp is just below the SMA relay, and the round power 1-watt amp is top right. (Photos by N6IZW) |
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In the Winter 2004 issue of CQ VHF I described a phase-locked synthesizer reprogrammed to 1152 MHz. This is a conversion that does not require exotic test equipment to change the synthesizer from its commercial frequency and mode of operation into one for amateur use. The 1152-MHz frequency is important not only for upper-microwave bandedge markers, but also as a local oscillator (LO) when coupled with a 144-MHz, 2-meter multimode radio. Construction of a 1296-MHz transverter cannot be far away. It is simplified by putting to use an older multimode 2-meter transceiver as a transverter IF driver. The “formula” is 1152 MHz from the synthesizer (low side LO injection) plus 144 MHz equals an operational frequency of 1296 MHz. While appearing to be quite technical, the synthesizer conversion described last time is easy to follow, producing a very accurate and stable low-phase-noise source for SSB operation or any other mode you care to use as a marker or for dual use in a 1296-MHz transverter construction project. This project was first brought forth by the San Diego Microwave Group when we were discussing improving interest and activity on the higher microwave frequencies. It was decided to attempt the construction of a different band microwave converter each month. While this sounds like a very ambitious project, we think that from a homebrew point of view it presents quite a challenge to our members and will warm up quite a few soldering irons during those cold months in garage ham shacks. To assist our microwave group and increase participation, we provide some of the component parts critical to this project, such as key surplus PC boards. This provides a starting point and incentive towards completion of the transverter.
Our group is not an official registered club.
There are no dues and no rules, just camaraderie in the pursuit of a
common interest—amateur radio and microwave operation. We have been
meeting for over ten years. We meet each Monday at 9 PM on the local
Palomar repeater (146.73 –600, no PL normally required) with the
permission of the Palomar Amateur Radio Society. Kerry Banke, N6IZW, is
our net control. The exception is the third Monday of the month, when we
meet for our once-a-month meeting at Kerry’s home. Swapping electronics
issues, equipment calibration, and repair of equipment are normal using
Kerry’s array of test equipment. The goal is to give assistance and
promote interest in construction ideas using surplus material. Projects
include working transceivers from 1296 MHz up through 47 GHz and a
full-duplex laser communicator. The challenge this time was to make a
1296-MHz transverter before the next month’s meeting. Click here to return to this month's highlights Click here to subscribe to VHF and read more about Microwaves _________________ © Copyright 2004, CQ Communications, Inc. All rights reserved. This material may not be reproduced or republished, including posting to a website, in part or in whole, by any means, without the express written permission of the publisher, CQ Communications, Inc. Hyperlinks to this page are permitted.
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