NASWA Journal Columns · Equipment Reviews

Alan Johnson, N4LUS • 2490 Sharon Way • Reno, NV 89509 alanjohnson◊gbis.com

Equipment Reviews, May 2008

Microtelecom Perseus Software Defined Receiver

A sea change has occurred with receiver technology. Over the past three decades, digital technology has gradually supplemented and then replaced analog circuitry in modern radios. At first, microprocessors were put into radios for tuning and function switching and external computers were used to control receivers. The next transition was the replacement of hardware by software (digital signal processing). Now, we have reached the point where the computer (with the addition of a couple of outboard intergrated circuits) is the radio. Not only has the internal hardware of the receiver been eliminated, but the control hardware of knobs and switches has been replaced by a computer mouse.

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Equipment Reviews, April 2006

Sherwood Engineering SE-3 MK III Synchronous Detector

Have you ever noticed in the receiver reviews in Passport To Worldband Radio that the reviewer may think that a particular radio is very good, but that the addition of the Sherwood SE-3 synchronous detector makes it great? What does the SE-3 do that makes it such a useful addition to an already good receiver? I had used an earlier version of the SE-3 with a JRC NRD-515 many years ago, but I decided to see what was different with the new model and see how it worked with more modern receivers.

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Equipment Reviews, January 2006

The Eton E1XM Portable Receiver

This is probably the longest anticipated product release in the history of the radio industry. The Grundig Satellit 900 was announced in the 1996 edition of Passport To World Band Radio, with an anticipated release date of “early 1996”. It was to be the replacement for the Satellit 700. Here we are almost ten years later with (finally!) the introduction of the Eton E1, which has a physical appearance almost identical to the early prototypes of the Satellit 900. Interestingly, this renamed radio will receive satellite radio, a form of broadcasting that didn’t exist when the original Satellits were produced. It is produced by Eton, which took over Grundig’s radio line and the new receiver is manufactured in India. Allegedly, the R. L. Drake Co. was involved with the engineering of the radio, which I think is entirely likely as it shares several features with the Satellit 800 and Drake appears to be providing service support. The street price is $500. Was it worth the wait? Is it worth the price?—let’s see.

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Equipment Reviews, January 2000

RF Systems P-3 Preselector

I jumped at the chance to review this unit when Fred Osterman of Universal Radio gave me the opportunity, having been alerted by a mention on Radio Nederland’s website that the P-3 was on the way. Why all the excitement about another black box? Because the one fault of modern receivers is their lack of front-end selectivity.

Back in the old days before digital frequency synthesizers, most quality radios had a tunable radio frequency amplifier as the first stage after the antenna input. This amplifier was tuned either in conjunction with the main tuning or, in some radios, the stage was tuned with a separate “preselector” control. The main reason that this stage was required was to reduce the problem of “images”-signals that were twice the intermediate frequency away from the desired signal. With the advent of high (>30 MHz) first IFs, image rejection could be accomplished by a simple low pass filter at the front end of the receiver. Along with the switch to digital frequency synthesis and equipment minaturization, mechanical parts such as variable capacitors, wafer switches and slug-tuned inductors became expensive and difficult to obtain. As a result, the tuned front-ends of yore were replaced with fixed bandpass filters covering an octave or more, or no filtering at all.

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Equipment Reviews, November 1999

The Icom IC-R75 Communications Receiver

The IC-R75 is Icom’s re-entry to the HF-only desktop communications receiver market after the R71A was discontinued. Yes, there was the R-72, but this receiver was poorly received by the SWL community. This leaves Icom as one of the few Japanese ham radio equipment manufacturers that hasn’t written off the SWL market. The R75 is a definite step-up from the R72 and rated specifications are closely equivalent to the R-71A. The R75 is a triple-conversion digitally synthesized radio, but signal processing and filtering are analog in nature. There is provision for adding a DSP audio processing unit for noise reduction and automatic notch filtering. The R75 has a list price of $950, but the street price is very attractive at less than $800, making it a competitor to the Drake SW8. For a receiver in this price class, there is a high degree of flexibility in configuring the various operating parameters of the receiver.

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Equipment Reviews, September 1999

The NASA HF-4 Communications Receiver

I don’t know the background to the name changes, but the NASA HF-4 is clearly a refined version of the Target HF-3 receiver that I reviewed in the April, 1997 Journal. The HF-4 is now distributed by Deltron Communications International.

For those who who have access to the HF-3 review, I’ll list the changes made in the HF-4. The major changes are: the inclusion of a 2.6 kHz filter in addition to the original 6 kHz filter, a lighted display panel, expansion of the available memory channels from one to ten, addition of a RS232 jack to permit reception of weather fax transmissions (PC software and cable included) and substitution of a SO-239 antenna connector for the RCA jack used on the HF-3. In addition, there is a back-panel slide switch to apply 12 volt DC power to the antenna connector to be used with the NASA AA-30 active antenna or any other active antenna that can be remotely powered.

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Equipment Reviews, June 1999

The Sony ICF-SW07 Portable Receiver

Sony Electronics has been the market leader in the microminaturization of shortwave portables with “serious” perfomance. The trend started with the SW1 in 1989 and the concept was refined and further reduced in size in 1995 with the introduction of the SW100. The SW07 is slightly larger than than the SW100, but has several enhanced features, primarily in the area of memory management.

The ICF-SW07 follows the receiving “system” principle established by its predecessors, i.e. the radio comes with an active loop antenna, antenna control module, AC power adapter and stereo earphones. The AC adapter sold in the U.S. can only be used on 120 volt AC mains. There is a leatherette carrying case for the radio and a drawstring cloth bag for the antenna. The radio requires two “AA” batteries for portable power and the antenna control module requires an additional two “AA” cells. Battery life with alkaline cells is specified at approximately 32 hours when the radio is used in FM mode and 23 hours in AM mode. List price for the system is $529 with a street price of around $420.

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Equipment Reviews, December 1998

The Ten-Tec Model RX-320 PC Radio

This has been one of the most fun-to-use receivers I have ever tested — I think that any SWL with a computer would love to have one of these radios! Since the radio’s control functions and most of the signal processing are done via software, the radio has a fantastic price to performance ratio, with a price of $295 plus shipping. The Ten-Tec RX-320 is a 3 x 6.25 x 6.5 inch black metal box that plugs into a serial port of a personal computer running Windows 3.1 or 95. The computer must be a 386 or better and have at least one megabyte of free hard disk space available. The DSP functions are handled by a chip in the receiver, so processor speed is not important for receiver performance. I used a 200 MHz Pentium and response to commands was almost instantaneous. The receiver is supplied with a 9 pin (DB9) serial cable, AC adapter, a patch cord for connecting the receiver’s audio output to the computer’s sound card line input, control software on a 3.5 inch diskette and a telescoping whip antenna which screws into the radio’s circuit board via a hole in the top cover. Provision for an external antenna (RCA phono connector) and an external 4 ohm speaker (1/8 inch jack) are available on the radio’s rear panel.

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Equipment Reviews, October 1998

The AOR AR7030 Plus/NB7030 Receiver

One of the things that I really like about the AOR AR7030 receiver are the extensive number of options that are available to customize the receiver for a particular type of listening. AOR has added even more options with the release of the “Plus” version of the ‘7030, the FPU7030 microprocessor upgrade and the NB7030 noise blanker and notch filter.

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Equipment Reviews, July 1998

The Lowe HF-150E Communications Receiver

Since its introduction in 1992, the Lowe HF-150 has won kudos for its small size, easy operation and excellent sound. It offers good performance for program listening and reasonable DXing capability. Although it has only two IF bandwidths, the selectable sideband synchronous detector can be quite effective in rejecting interference. When equipped with internal batteries and an accessory whip antenna it is at least transportable, if not the equivalent of a true portable. In the past, it has been fairly priced and offered good value.

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