Have it

The R8 is like a breath of fresh air, with its ground-up engineering and up-to-date digital control from the front panel I am very pleased to see a quality HF receiver of American manufacture that should successfully compete on the world market,

Bill Clarke 73 Amateur Radio Today

When we introduced the American-made R8 Worldband Communications Receiver, we knew it would be Judged by some very discerning ears, experts accustomed to the finest in short-wave listening equipment from around the world, After listening to the world on the Drake R8 loud and clear, they have delivered a decisive verdict.

They appreciated the R8's sensitivity, clarity, simplicity, and all-around versatility so much that many of them declared the R8 simply the best of its class. High prase, indeed, from very well-traveled ears.

But why take the word of mere

R.L Drake Company P,Q, Box 3006 _ Mrarnishurg, OH 45343 CIRCLE 147 ON READER SERVICE CARD U.S.A.

experts? Put the Drake R8 to the test yourself with a 15-day money* back trial period on factory direct purchases, and let your ears be the judge. If youYe not impressed by Drake's quality, performance and ease of operation, all in a receiver costing less than $1,000.00, return the R8

______Receiver within 15 days, and we'll refund your money in full, less our original shipping charge. To order your R8 factory direct, for more information, or for the dealer nearest you, call 1-800-723-4639 today. We're confident that once you've listened to the R8, your ears will hear of nothing else.

In touch with the world.

73 Review by Peter H. Putman KT2B

The Down Microwave WSSfiC

Microwave weak signal source kits.

Down East Miaowave RR1t Box 2310 Troy ME 04967 Telephone; (207) 946-3741 Fax; (207) 948-5157 Price Class: Complete kit, $65; assembled board, $88; assembled in a box, $120,

To paraphrase a current beer commercial, "Wouldn't it be great if someone made a simple, reliable and inexpensive signal source for the microwave bands?" Well, someone does, and they're called the WSS903K. WSS1152K and WSS1296K kits from Down East Microwave. All three kits can be assembled in one evening (if you're so in-dined) and feature on board interdigital filters, MMIC stages for stability, and a no-tune design.

How They Work

All three sources use a two-stage oscillator/buffer, working anywhere from 90 to 110 MHz, followed by an MMIC amplifier, diode multiplier and two additional MMIC amp stages- Output Is typically in the 1-to-3-milh-watt range, which is more than adequate tor aligntng preamps and mixer stages. The WSS903K is designed for an output frequency of 903.100 MHz using a crystal frequency of 90.3100 MHz, white the WSS1296K pops up at 1296.100 using a 108,0833 fundamental. On the other hand, the WSS1152K Is probably the most versatile of the three, with usable harmonics all the way up to and including the 3 cm band (10.368 GHz), It can be used at 2304, 3456, and 5760 MHz as well, and for just fooling around it makes a great local oscillator (add 144 MHz, and mix to get 1296 MHz output).


Assembly is very easy. You'll need to wind four coils using a 0.1'-diameter drill bit and #24 enameled wire, supplied in the kit Two BFX89 transistors are used in the oscillator stage, followed by a MAR-3 MMIC, an HP 2835 multiplier diode, a MAR-6 MMIC and another MAR-3 for output. About a dozen chip capacitors are included, and you'll need to use a smalt pair of needle-nose pliers and a low-wattage iron to solder them in place. Keep alt leads as short as possible on the coiis and resistors. This isn't hard to do as you can lay each component on top of the board and cut the leads according to the solder pads. I did find some variation from the coil windings in the instructions for the WSS1152, and changed L1 from 10 turns to 11 turns, gaining 3 dB more output and

Photo A. The Down East Microwave l/VSS (Weak Signal Source) kits can be ordered for outputs on either 903.1 {WSS903KI 1152 (WSG1152K) or 1296 MHz (WSS1296K).

putting the crystaf right on frequency {96.0020 MHz).

A good frequency counter would be helpful to check the crystal and trim ft in, but if you have a receiver for any of these bands and you know the calibration, just make a note on the board with permanent marker. If you want to be sure of your frequency, allow the unit to warm up and! stabilize for a bit . . . say 10 minutes or so,

Down East offers an option to get a bit more ^oomph" from the board by adding another MMIC stage just before the output connector. The parts for this stage (another MAR-3 MMIC, a 220-ohm 1/4-watt resistor, and a 22 ^F chip capacitor) can be ordered at the same time for a slight additional cost. You'll have to wind another eight-turn 0-1" diameter choke from #24 enameled wire as well

In Use

Down East suggests a Radio Shack 270238 box for installation, I would prefer to use a small Hammond or Bud die-cast box with a BNC or SMA connector and feed-throughs for

DC power. The board is small enough at 3P x 5* to fit in just about any configuration, and you could put all three together in one box with a power supply and just switch to the desired port. I've used mine to check the sensitivity of several GaAsFET preamps 1 use on 33 cm, 23 cm and 13 cm, Although the crystal stability would be far better with an oven, drift is pretty minimal after warm up and gives you an easy way to find yourself on any of these bands, especially if you're trying to work another microwave station on a schedule.

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