Living with the Kaito KA1103


The Kaito KA1103 as a MW portable

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The Kaito KA1103 is compact little radio with surprising capabilities. It's only 6 1/2 x 4 x 1 inch thick, with a solid, but not heavy, feel to its case, and looks like a mini portable radio of 25 years ago with an LCD screen showing a simulated analog dial with FM, AM and 10 shortwave broadcast bands. Once switched on, it actually has a digital readout good to 1 kHz, controllable either by a knob or by a 10 digit row of keys under the screen, and, in spite of the 10 shortwave bands shown, it does tune from 100 to 29999 kHz.

Power - It comes with a wall transformer power supply, and its own rechargeable batteries, that can be charged while in the radio.

Features of particular interest to the DXer are dual conversion, two IF filter bandwidths, SSB capability, an external antenna input, DX/local switch, and both stereo headphone and line out jacks.

Reading - Other reviewers have described the radio (see www.radiointel.com for an example), so I'll not dwell too much on its shortwave capabilities, or on the detailed use of alarms, scanning, memories etc.
If you want to examine the radio's specifications and modes of operation in detail, the operator's manual can presently be found at www.amazon.com/exec/obidos/ASIN/B0006OCEFY
(be warned, 6MB; way bigger than one would expect for the amount of information).

Benchmarks - I'll compare this radio with the Sony ICF-2010, and without use of any external antenna, beyond adjacent tuned loop antennas, as it quickly became apparent that the KA1103’s external antenna connector is only functional above 1710 kHz.

Something that will strike you quite early on after switching on the radio, is that there appears not to be a volume control. In fact, it shares a single knob (the "jog dial") with the tuning function, something that some have found objectionable.

I surprised myself by finding this out without recourse to the manual, and given that the radio's AGC action seems effective over quite a range, I rarely adjusted the volume anyway.

Tuning is by direct entry of the frequency using the keys, or via the jog dial knob; there is no "chuffing" sound as one advances kHz by kHz using the knob, but a slight click is still audible under quiet conditions.

The analog dial bands are not just decorative, as you can get "trapped" in any of the bands if you try to tune outside the range of a band once you're in it (you have to enter a frequency beyond 1710 if you're in the MW band and want to tune beyond it, for example).

{mosimage}If one doesn't want to tune 1 kHz at a time, or by entering a new frequency on the keypad, the memories (up to 268, they claim) could be used to hold 9 or 10 kHz MW frequencies, which could then be selected by turning the knob.

OK, how does it work?

You might expect a radio this inexpensive (under US$100) to have problems with sensitivity or with signal handling, but in fact, performance is quite respectable.

Signal Handling - I have just two local stations, but both put very good signals into my antennas from a few kilometers away across salt water; it's pretty easy to predict where their mixing products will show up.
Indeed, there are a couple that show up on this radio in the daytime, 170, 730 and 1240 kHz, but they also show up on the ICF2010.

The 1103's DX/local switch put to "local" kills the 1240 spur, leaving 1kw KGY from 150 km away, weak but clear. The spur also disappeared from the 2010 when its attenuator was used, but KGY was not always audible.
The 730 spur disappeared on both radios when attenuation is used, but 170 kHz remains at a lower level on both. No other spurs or images were noted on the MW band with the 1103. However there was bleed through from a couple of semi locals on 210 and 230kHz on the 1103's longwave band.

Sensitivity - This radio is definitely pretty sensitive. As always, when I test a radio, conditions collapse, but both R. Vision Cristiana-530 (>5000 km away), and JOUB-774 (>7000 km away) were audible on the barefoot ICF-2010 for brief periods. The barefoot KA1103 was never far behind in reception of these two signals.
The sound quality was somewhat less fuzzy on the 2010 however, and as the signals were sometimes strong enough, the 2010's selectable sideband synchronous detector was able to deliver a definitely more readable signal that the 1103 could, by avoiding the worst of the sideband splatter. Similar observations were made with daytime signals on 530 and 750, but 1640 kHz delivered slightly more readable, though still weak, signals on the 1103 compared with the 2010. Given that the 2010 was pretty much the most sensitive MW portable for many years, this is a pretty fine performance from a radio a fraction of the 2010's price.
Both the 2010 and 1103 gained signal readability and strength on weak signals by being placed inside a 1 meter square tuned loop, though one has to be careful not to mistune the loop to the local stations, as overload can occur.
As noted, unlike the 2010, the 1103 doesn't have the advantage of a usable external antenna terminal which limits the easy use of outdoor antennas with this radio. Wrapping a couple of turns of wire around the radio and hooking up a random wire can introduce overload in this location; a tuner would be a good idea.

Selectivity - Even in its wide IF filter setting, this radio is reasonably capable of separating out the 10 kHz domestic channels, but the narrow filter does a better job at night, even to the point of getting stations within 10 kHz of my locals. As noted above, 774 kHz wasn't a problem, though, unless a split is strong, I suspect much closer to the domestic channels might be more difficult. But I was able to receive audio from 4QR-612 by tuning to 614kHz, so closer is possible. (This was putting the 1103 inside the tuned box loop, not barefoot!
But with 50kw at >11500km, this was a fine catch.) My locals had readable signals from +/- 6kHz of their assigned channels using the wide IF filter. The narrow filter showed the locals readable at +/- 3kHz , but by +/- 4kHz were mostly splatter.
The 2010 by comparison shows readable signal from 897.0 to 903.2kHz (note that the 2010 is capable of tuning in 0.1kHz steps).

S-meter - Yes, this radio has a 9 position indicator for signal strength on the LCD, and shows some useful dynamic range. However, it is actually a "0-2-4-6-9 bar" indication, so there are effectively only 5 signal levels indicated. Still, it's helpful when looking for a station null when using the radio barefoot, or for a peak when boosting the signal with an external tuned loop.

AGC - As already noted, the radio's AGC is effective over a reasonably large range of input signals. Any signal that indicated on the signal strength display changed very little in audio output when the signal was peaked up with the tuned loop, even as the S-display maxed out. There was no concern about AGC recovery when tuning from a strong signal to a weak one 10kHz away, and strong subaudible heterodynes didn't "pump" the audio output as badly as the 2010 did when tuned to the same channel.

Audio quality - Given the small speaker, audio quality was acceptable, and was more so using headphones. The 2010 did have a somewhat crisper sound when using the narrow filter than the 1103 did, however, which aided readability of marginal signals. The line output seemed a little more bassy when fed to headphones through a PC soundcard or stereo amplifier, than when feeding the headphones directly from the radio. But, that is a small complaint, given that there is a line output at all (it's stereo by the way, so you can tap off stereo FM if you so choose).

SSB - Although the KA-1103 has SSB capability, it is really only useful for carrier detection on MW. The continuously variable SSB fine tuning control does allow reasonable demodulation of true SSB signals on other bands however.

Conclusion - If you're looking for a good starter radio for MW DXing or a light and compact DX capable portable radio for travelling, the Kaito KA-1103 is probably the best bet there is today. It is inexpensive, and has sensitivity, selectivity and signal handling capability easily comparable to considerably more expensive portable radios. It would be nice to have a working external antenna jack for MW use, and selectable sideband synchronous detection for digging out the splits, but at this low a price, these are quibbles. (thanks to Walter Salmaniw for the loan of his KA-1103) (this article originally appeared in IRCA’s Technical Column) - {mos_sb_discuss:12}
Veteran radio technologist and writer, Nick Hall-Patch lives and works in Victoria B.C. Canada - He is a regular contributor to the DXer.CA website, the author of various IRCA technical guides and a host of other great things.

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