ENIGMA 2000 Newsletter - Issue 9

March 2002
Articles, newsreports and Items of interest : e2k_news@hotmail.com

Review

Instead of a book review we have an equipment review by 'P' and a idea on antenna connection:

Sony ICF-SW100E Receiver

First sight of this little box of tricks made me think that it was a toy. The diminutive size hides a very sensitive and useful receiver. Measuring just 110 x 72 x 22mm it compares in size to a packet of king-size cigarettes and weighs just 240g when complete with batteries [2 x AA]. A retractable antenna folds neatly away, within the stated dimensions and is no way obtrusive. The controls are protected by a hinged cover which, when raised, reveals the 30mm dia speaker and LCD for the dual clock, frequency and memory annunciators. Twenty-seven controls, if that is the right word, turn the device on, allow the clock to be set, input memories, change mode, tune frequencies and so on. I was concerned that there was no rotary control to precisely adjust the frequency and felt from the onset that this was a hinderance. After using the set over 14 days my opinion changed as becoming familiar with the set allowed me the same control of frequency as I have with my other receivers, including using SSB for datamodes. The LCD is 'split' into designated areas with the largest section more than adequately displaying the frequency, whilst the rest is concerned with the accessing of the 50 memories there is no compromising for space.

To turn the set on a simple button provides an on/off facility whilst a green slide switch on the side of the case provides master control to stop an accidental switch-on.

FM [for the 76 to 108MHz band]. The ICF-SW100E little receiver allows HF reception with AM, Sync AM, LSB, USB modes between 150 to 29999kHz and FM for the 76 to 108MHz band.

[There are two versions of this receiver. The Italian version, ICF-SW100S tuning between 150 and 26100kHz, missing 285 to 530kHz and 1620 to 3850 kHz also. The VHF freqs are likewise modified to cover just 87.5 to 108MHz, to keep within the Italian regulations].

Around the sides of the receiver case are other controls. On the left side is the master on/off switch already mentioned, next are two sockets, the first being a miniature barrel socket for an external 3v DC supply, the second being a 3.5mm jack to permit the use of the active antenna pack AN-100. A slide switch next to this allows control of receiver sensitivity. Marked DX and Local the difference is well noticeable with strong signals, including those on VHF.

The front edge of the case has only a catch, which adequately secures the cover. On the right edge is the edgewise volume control, a tone control. Marked News and Music for AM use the difference is obvious as the base freqs give way for the treble. On FM band use the switch selects between mono and stereo, the latter being apparent when using the earpieces supplied with the receiver. Two 3.5mm sockets allow 'Line Out' for recording [very adequate level] on one and use of earpieces via the other.

With such a tiny speaker, and cover mounted, one would have expected a tinny, inadequate response usually associated with small area acoustics. The design team have done well here placing a vent on the cover in the right place.

Although other packs sold world-wide include the active antenna AN-100 us Europeans have to believe the claims from Sony that we do not need such a device. As compensation for this the pack does contain the AN-71 compact antenna. This compact antenna consists of a circular case of 68mm diameter which contains 5M of wire which terminates in an impressive clip. The case has a cord and plastic clip to allow the antenna to be held aloft whilst the other end clips onto the retractable antenna. I used it once and then put it away as a bad job firm in the knowledge that a little inventiveness would allow me to use any antenna of my choice. [See later].

The specifications state the usual 10.7MHz IF for FM whilst for the LW/MW/SW use 55.845MHz first IF and 455kHz for the second IF. The power output into the mini-speaker is stated as 250mW at 10% harmonic distortion. [I found the set performed well at the levels which I used]. The recording output is a healthy 245mV [-10dBs] assuming 10k impedance. The headphone jack is stated as being suitable for 16R impedance headphones. [Playing the output of XPH direct into an RM PC and observing the resultant acoustic display is also possible, as is driving Radioraft from the line socket].

As regards the antenna input it was obvious that the telescopic antenna would not be suitable for weak stations. As a result it seemed feasible to me that the active antenna socket was a sensible way to proceed. Placing an un-terminated 3.5mm stereo plug into the socket allowed me to place a multi-meter across the terminals and find a voltage of 2.85v present. I took a small plastic box into which I fixed a BNC socket and 4mm socket. A piece of miniature coaxial cable was terminated to the BNC socket with the voltage isolated by a 470nF capacitor on the centre conductor, its reactance calculated as being favourable to HF freqs. This arrangement has worked well with a covert longwire antenna, installed at work, as well as variation on the 'snake' ground antenna at home.

The tuning steps as you push the respective buttons are 100Hz or 1kHz steps and allow adjustment to frequency with care.

The 50 memories are held on 10 pages in batches of 5. They can be labelled; page 2 on mine reads 2/1 S17C, 2/2 S17C, 2/3 S17C, 2/4 M10E, 2/5 S10E. The freqs are displayed under the labels.

The supplied book of instructions is just adequate; it is easy to work out the variety of functions and how to select them. All in all the set is a worthwhile purchase. For my part the method suggested for an external antenna input was disappointing but easily sorted. The greatest omission is the 'S' Meter. I am considering designing one which can be used via the line out socket. For number stations the set performs well. The antenna that I connect is 60 foot of 1/0.6 insulated wire laid in the flowerbed at the rear of my house.