| TA2EI |
Rating:  |
2008-11-17 | |
| Dissappointment |
Time Owned: more than 12 months. |
Alinco declares that their DJ-X3 receives from 100 kHz to 1,299.995MHz at their web site.
Unfortunately DJ-x3 has an odd step size at LW. i.e. after 153 kHz it tunes to 153, 162, 164, 171, 189,207,209,216,218,227,234 kHz. There are some "no-tune" areas. 18 kHz between 171 and 189 kHz, 15 kHz between 209 and 216 kHz etc.. There is not any information about this trouble at their web site.
Anyway, DJ-X3 is not a sensitive radio at LW, MW, SW and air band.
It is not suitable for a HAM. |
|
| N5NSL |
Rating:    |
2003-11-02 | |
| Good Radio, but controls need to be learned |
Time Owned: 6 to 12 months. |
The Alinco DJ-X3 is a wide-band scanner which is continuously tunable from 100kHz to 1.3GHz (cellular frequencies permanently locked out for USA versions), with additional modes for receiving the AM, FM, and TV broadcast bands. I liked the radio for it's small size, to the point display, interchangeable battery packs, and physically simple control layout. There is many things this radio can do, this only lightly addresses it's many capabilities.
The Good:
The radio also has internal ferrite bar antenna which is used for frequencies below 30MHz. On the ferrite alone, it will pick up local stations in town and in rural areas DX broadcast AM and stronger shortwave stations. The radio has two menu selectable settings whether to use the built-in ferrite or the external antenna for broadcast AM and shortwave. For frequencies above 30MHz, it has the option to use either the earphone cable or external connector as the RF input. By using the internal ferrite and earphone cable, the radio can cleanly receive signals without an antenna connected to the external SMA antenna connector.
When scanning, the radio can scan either 10 (memory) or 20 (VFO) frequencies per second, and can scan by memory (up to 700 entries), or scan linearly by a preset step. The memory entries may be individually locked out and store both frequency and demodulation mode (AM, narrow FM, or wide FM).
In addition to VFO and memory tuning modes, the DJ-X3 has additional tuning modes for broadcast AM, FM, and TV. In the AM tuning mode it demodulates AM and tunes from the standard 520 to 1620 kHz. In the FM tuning mode it demodulates wideband FM and tunes from 87.5 to 107.9 MHz. In the TV tuning mode, it demodulates wideband FM at the audio carriers for NTSC television channels 2 through 69.
The radio also has memory clone capability between two DJ-X3s, where the memory contents of one DJ-X3 can be copied to another DJ-X3 using an ordinary stereo 1/8" patch cable. The radio's frequency memory is also PC-programmable through a special cable available from Alinco for $35.00 (or tech-user buildable if one has the schematic and tools). But cellular-band and descrambler modes are permanently ignored/unavailable for USA versions due to legal restrictions and ECPA laws forbidding the reception of cell phone narrowband FM.
The Interesting:
The radio has a great amount of functionality, all accessible by only seven controls. Except for linear tuning, band mode, scan start/stop, and power on/off, every other function is accessed by various combinations of the buttons and rotating and pressing the knob. It takes some time with the radio to learn the button combinations, but the radio is moderately easy (and slightly tedious in a few circumstances) to use and program once the combinations are understood.
Also the free-rotating main knob is detented by a gear which gives a tactile click every 18-degrees of rotation (20 clicks per full revolution of the knob). The knob also makes an action only at these 18-degree points and in rotation controls volume, squelch, frequency linear tuning, and parameter setting. The knob also functions as a button and in pressing the button selects among various parameters including volume, squelch, step rate and 17 other control parameters. There is a concave dot at the top of the knob, but it's meaningless with respect to the knob's functionality.
When in wideband FM mode, it will demodulate 38kHz carrier stereo whereever it occurs, not just on the "standard" FM broadcast band. This is useful for tuning in "wireless speakers" from VHF and UHF frequencies, short-range intermediate transmitters around 49MHz which use FM broadcast stereo modulation mode, and some FM signals in other countries which transmit below 87.5 MHz.
The internal ferrite antennas are influenced by large antennas connected to the ring of the antenna connector. RF from the antenna will have some inductive coupling to the ferrite coil from the unavoidable near proximity of the ferrite and external antenna. This only seems to occur when a moderately big antenna (200 foot wire in town) is connected. Connecting a BNC-ended whip doesn't collect enough RF to allow inductive coupling. On shortwave, this increases sensitivity when a direct connection will overload the receiver and using ATT will overattenuate the signal.
External antennas are connected through a SMA connector, which is a new kind of a "sub-sub-mini-UHF" connector along the threaded coaxial philosophy of the TNC and mini-UHF connector designs. Alinco, Yaesu, and many other (mostly Japanese) manufacturers are increasingly using SMA connectors for antennas. The radio's SMA connection works well with BNC equipment through a SMA-to-BNC adapter. Unless one intends to use only the supplied antenna or the few SMA antennas out there, a SMA to BNC adapter is required to use most of the available external antennas. Also BNC connectors don't require screw-in threading like SMA connectors do (and thus attach/detach more quickly).
Tuning is generally linear, with options to tune by a particular kHz step per click of the knob: 5, 6.25, 8.33, 10, 12.5, 15, 20, 25, 30, 50, 100, or Auto. The user can also select the 1's or 10's digit in the MHz portion of the display and tune up or down 1 or 10 MHz per knob click. This accelerates tuning significantly. Not all frequencies in a range can be tuned, but in the AM , narrow FM, and wide FM demodulation modes, the small gaps are insignificant. Most of the easily tunable frequencies usually fall on frequencies used in band plans, but various interstitial frequencies can be tuned, but with more work.
The radio tunes shortwave, but only down to 5kHz steps and then only in a wideband AM mode. While it does tune shortwave signals, it can't tune down to the kilohertz or narrow-AM, sideband, or CW modulation.
Also, the single mono speaker is center-mounted behind the display with two ports on either side of the display for the sound to escape the case. Although there are two ports and the radio internally does have two audio channels (right and left), the speaker corresponds to both channels combined (R+L) of the two-channel audio. (The right and left ports are unrelated to the internal right and left audio channels.) On good headphones the sound quality is good. The built in speaker has the sound quality typical of a small mono speaker. At maximum volume on FM broadcast, the audio amplifier clips very slightly, almost unnoticably. For voice communications, the speaker works very well.
The Bad:
The radio is actually an excellent receiver, but I've never met a perfect machine of any kind anywhere. Following nature, the DJ-X3 has a few problems and irritations. Most of the problems are very minor, with some of the problems common to many scanners.
Among the minor problems I found were the idea of combinational use of the few buttons. Although the radio is very easy to use /after learning the buttons/, the initial experience with the buttons is confusing--the control philosophy of the radio is not straightforward or similar to prevailing control philosophies, and going among the modes and frequencies can be tedious in some circumstances.
Other minor problems regarded some of the case-design issues. The battery pack contacts the spring-loaded belt clip. As-is, removing the inserting the back-mounted clip will tend to scrape off the paint where the pack contacts the clip. (This was easily corrected with a fashionably cut and set piece of electrical tape to protect the section of the pack which contacts the belt clip.) Also, the earphone and external power jacks are covered by rubber covers, but an unused opening in the case next to the top mounted earphone jack is also covered by a rubber cover piece which looks very much like the earphone jack's cover, isn't intended to be removed, but has the same general shape and retaining strap like the earphone's cover. This cover once removed is extremely difficult to reseat back into the case.
Also, the main knob's detented click is relatively loud compared to other detented knobs from most other manufacturers. In typical use, the knob itself emits clicking and zipping noises which can be heard up to about 60 to 100 unobstructed feet away in a quiet environment. When making wide frequency changes and/or multiple mode adjustments, such changes can entail about 20 to 30 seconds of clicking and zipping noises as the user operates the knob. For those not listening to the radio, all that clicking and zipping may become irritating.
Also, the radio can have some intermodulation issues where a transmission on one frequency appears at a different frequency on the DJ-X3. When scanning, the signal being received is almost always, but not certainly, on the indicated frequency. (I've seen this on other makes and models of scanners also, so this isn't unique to the DJ-X3.) My commentary about DX-ing AM and shortwave in rural, but not urban area referred to intermodulation when transmitters are nearby. When in urban area near powerful transmitters connected to very large antennas, the radio will cheerfully exhibit overload-based intermodulation up to 100MHz or so from the radio's tuned frequency.
Conclusion:
The DJ-X3 is a good radio for VHF and UHF, once one knows how to use it. Although it has plenty of design oversights which limit it's potential, for most radio receiving it's a wonderfully compact and extremely capable receiver. |
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