Equipment Reviews, July 1996
Sony ICF-SW40
NASWAn Koji Yamada of Tokyo sent me a copy of the instruction manual for the new travel portable from Sony. It measures 6 3/4 x 4 1/4 x 1 7/16 inches and weighs 14.5 ounces, including batteries. Shortwave frequency coverage is from 3850 to 26100 kHz and tuning is via a side mounted knob in either 5 or 1 kHz steps on SW. There are twenty frequency presets and, as I read the instructions, all twenty presets can be used for SW, if desired. There are timers for two “On” events–the radio shuts off after 60 minutes. According to Koji, the price in Japan is 22,000 Yen or about $230. I would expect the price in the North American market to be lower.
Kiwa Electronics
I recently received an updated catalog from Kiwa Electronics. Their product line continues to expand with the addition of the Pocket Loop, a collapsible 12.5 inch diameter air-core loop which tunes from 530 kHz to 23 mHz and includes a noise generator for tuning the loop. It is designed for use with portable receivers and costs $120. There is also a full-size air-core loop covering the tropical bands (1.8 to 7 mHz) which will be available in the near future. Also listed are the SW Preamp and BCB rejection filter which are $99 and $60, respectively. Kiwa can be reached at 612 South 14th Avenue, Yakima, WA 98902; (509) 453-5492 or (800) 398-1146 for orders. The inclusion of a first-class U.S stamp would be appreciated for catalog reuests via mail. The Internet address is kiwa@wolfe.net and the Web site is http://www.wolfe.net/~kiwa/.
Kiwa Electronics has expanded its line of accessory filter modules with the new Premium Filter Modules. These are available in a variety of bandwidths and feature excellent specifications. The most notable spec is the ultimate rejection (rejection of signals outside the filter’s passband). The Kiwa premium filters have typically 105 dB of ultimate rejection vs. 80-85 dB for ceramic filters and 90 dB for mechanical filters. The Premium Filter Modules are also designed to be extremely low-noise. They are priced at $70 each, plus $4 shipping in North America and $7 elsewhere.
Graphic Equalizers
Since it is currently yard sale and hamfest season, be on the lookout for reasonably priced graphic equalizers and stereo amps. This idea is certainly not original with me and has been suggested by many others over the years. Connect your receiver’s line or tape output to the graphic equalizer and the output of the equalizer to the stereo amp and speakers. It will not give you razor-sharp selectivity, but the equalizer can be used to reduce the low frequency rumble and high frequency hiss on SW signals. The audio response can be tailored to emphasize male or female voices as necessary to catch that elusive ID. It’s cerainly worth experimenting with, if the components can be obtained at reasonable prices.
Palomar Engineers
Two new products from this long-standing supplier of accessories are the P-508 active preselector for $99.95 (not including power supply) and the PD-600 add-on digital readout for older receivers, priced at $199.95. The company can be contacted at P.O. Box 462222, Escondido, CA 92046; (619) 747-3343; their catalog is free.
Noise Sources
In my seemingly never-ending crusade to eliminate RF noise at my present listening site, I recently made an interesting discovery. My VCR makes more noise when it is turned off than when it is on. I’m not sure why–perhaps it is related to the dimming of the flourescent display. Could it be that the dimming is accomplished by decreasing the pulse rate to the display and the lower frequency is more easily picked up by my antenna/receiver? Anyway, try this experiment at your location.
RayOVac Renewal Batteries
Rechargable batteries can offer significant cost savings over traditional carbon-zinc and alkaline cells and are more environmentally friendly. I had tried rechargable NiCad cells in the past, but was unpleased with their performance due to their lower (1.2 volts) cell voltage in equipment designed for the traditional 1.5 volt cells. Rayovac has recently introduced the Renewal series of rechargable alkaline cells with an individual cell voltage of 1.5 volts and an estimated life cycle of 25 recharges. The duration of each charge will vary depending on the current demands of the equipment being powered. Unlike NiCads, the Renewal batteries should be recharged prior to being completely discharged. These batteries can only be recharged in the Renewal Power Station recharger and AA and AAA size cells will recharge in 3-5 hours; C and D size cells will recharge overnight. The large Power Station (handles any combination of up to eight cells) costs about $30 dollars and there is a smaller recharger which only holds AA or AAA cells for about $20. Contact Rayovac at (800) 237-7000; 601 Rayovac Dr., Madison, WI 53711, Attn: Consumer Services, for more information.
How Long Should A Random Wire Antenna Be?
I recently had cause to comtemplate this question when putting up a random wire to complement my 90/60 meter dipole. I had originally planned to make the wire 140 feet in length, since Radio Shack sells antenna wire in 70 feet rolls, however, I decided to perform some calculations first. Theoretically, a single length of wire referenced to ground (sometimes referred to as a “Marconi” configuration) should be resonant at a frequency at which the length of the antenna represents a quarter-wavelength of that frequency. The formula is frequency in MHz = 234/length of the wire in feet. Such an antenna should also be resonant at frequencies which are odd multiples of the fundamental, i.e., 3/4 wavelength, 5/4 wavelength, etc. With the aid of my calculator, I found that a wire that is resonant at 1.95 MHz (approximately 120 feet) should also have resonant points in or near the 49, 31, 22, 16 and 13 meter bands. This appeared to be the case with the wire I put up. Remember that this is theory and an actual antenna’s response will vary with height above ground and nearness of surrounding objects. Any length of wire will work, especially when used in conjunction with a good earth ground and an antenna matching unit (usually referred to as an antenna tuner).
Com-Rad Industries Funtenna
I recently received a brouchure and review copies concerning this indoor passive antenna. It consists of a 42″ collapsible whip mounted on a plastic base which contains a twelve-position tuning switch. It is omni-directinal in response and the claimed tuning range is from 6.8 MHz to over 50 MHz. The included patch cord has a RCA type plug with a PL-259 adapter included. It is designed for indoor or portable use. It is a passive design, so receiver overload and decreased dynamic range are not a problem. The enclosed reviews stated that while the Funtenna should not be considered a replacement for an outdoor antenna, it did a credible job as an indoor/portable antenna. Com-Rad Industries can be reached at P. O. Box 88, Wilson, NY 14172-0088; (716) 751-9945 and is operated by Jim Waldron W1HGZ.
Drake Update
I sent a copy of my article in the April Journal about the updated Drake SW8 portable receiver to the folks at Drake and got a reply stating that there are two addtional changes that were implemented in January 1996 (the affected radio’s serial numbers will begin with “6”). The changes are extension of the lower end of the tuning range to 100 kHz vs. 500 kHz for the older receivers and the synchronous detector now features selectable sideband. This feature is activated by pressing the “SSB” key to toggle between either the upper or lower sideband while in the “Sync” mode. The letter did not mention whether or not this feature will be incorporated in the R8A. A flyer for the new SW1 was also enclosed. This is a general coverage receiver with a single bandwidth and AM mode reception only. It tunes in 1 or 5 kHz steps and appears to be very similar to the radio sold by the People’s Radio Network as the PRN-1000. It will be available sometime this summer and will be priced in the low $300 range. R.L. Drake Co., P.O. Box 3006, Miamisburg, OH, 45343; (513) 866-2421.