By 13dka

Following up on the article I recently wrote about the MLite-880, I still had a comparison with a reference radio on a proper antenna on my to-do list. I wasn’t in a hurry because I got pretty fascinated with exploring what I can get out of various magmounts on my car with this radio, which is quite a lot and it never gave me the feeling of missing out on something. I was also a bit hung up on the idea of comparing the MLite with the Belka because, you know, same price level and all, but that’s a bit iffy with my little passive splitter and 2 different input impedances.

Then a claim was made on the interwebz that the MLite-880 would be just a mediocre radio that would not stand scrutiny without its outstanding noise reduction, to summarize that in my own words. My experience is obviously very different and it made me curious how much truth could be in this claim. So I just took the ingenious Icom and the mediocre MLite to the dike to slip in a little shootout and then maybe give the loser a Viking funeral on a little raft I improvised out of flotsam and jetsam while making a lot of recordings to give my findings a whiff of evidence.

Both radios were connected to my lazy 10m/33′ monopole antenna via a Diamond SS-500 splitter and 15m double-shielded and common-mode choked coax. Both were recording to their own SD cards, but unfortunately, the recorded audio from the Icom does not represent the live audio off the radio on AM recordings because it records to an SD card with an 8 kHz sample rate, and that limits the audio bandwidth to at best 4 kHz.  The deciding thing to listen to in these recordings is the noise and sometimes the pure existence of a signal, though, and lower bandwidth is almost an advantage in this context.

Sensitivity Test

Since the question is really the practical sensitivity and, therefore, how dependent this radio is on its noise reduction to get good results, I’ll start with the IBP beacons, which were recorded without NR, of course. To spot and quantify SNR/sensitivity differences you can use the four -10dB stepped (100W, 10W, 1W, 0.1W) dashes the IBP beacons transmit after their callsign.

The most grassrootsy first: OA4B in Peru (10,800km/6,700mi) on the 17m-band. MLite first, then the Icom. Both radios receive the second (10W) dash as faintly as the 100W dash, but with too little SNR left.

5Z4B beacon in Nairobi, Kenya (6,600km/4,100mi with a 3rd dash = 1W!) informing a silent 15m band about the opportunity around sunset. MLite starts again, then the Icom. The latter has the 3rd dash faintly but clearly and the former leaves some more ambiguity about that. Demonstrates again the minuscule difference.

5Z4B again, but on 20m with a 4th dash to count, whether or not the last one is really from 5Z4B or just interference doesn’t matter; what counts is that both radios heard it. The 1W dash was clearly received by both, starting with the MLite.

Here’s one where only the MLite heard an interference, and I’m not sure it imagined it (absolutely unavoidable pun) – VK6RBP in Australia for the 10,000 miles bragging rights.

I think the conclusion here is that we could probably agree on “same ballpark”, right?  I don’t know about you, but imagine my surprised Pikachu face!

The AF SNR difference, which is probably all that counts in sensitivity tests, is within 3dB between the two, not to be confused with RF power decibels (but reflected on the RF side in comparably small amounts). For the interested:I did take day/night variations of the noise floor above 10MHz into consideration, with a decreased noise level around midnight on 21MHz, the MLite still matches the Icom, which is all that counts in this comparison (not absolute measurements) context.

The magic button

Another claim was made about the noise reduction, that it would only work with signals of a certain strength. While it is technically correct that it needs a minimum SNR to improve upon, my experience is that it is effective with almost any remaining SNR, provided the signal is fed into the NR with sufficient levels, and it exceeds all my expectations at that. Here are a few recordings of CHU demonstrating both points:

CHU 14670 kHz in Ottawa (5,800km/3,600mi) in bad enough conditions. The same announcement from the IC-705, then the MLite with NR at ?  of its range. Note how difficult the French announcement at the end of the transmission is for both radios. I will miss that station. The noise, not so much.

This is just the announcement a minute earlier, when the signal dipped below the noise floor. Nothing gets really recovered, but nothing gets lost either, and what’s left stands out more:

However, if you only look at its inability to cheat physics, you could be missing the point of a good noise reduction in this particular “shortwave radio” context. Restoring fidelity, removing masking noises and generally increasing the SNR and thus ease of listening is having a massive impact on how at least I can enjoy programs or conversations and there’s more: After a few decades many of us (particularly 2-way) radioheads have gotten their auditory cortices hardwired to make a connection between noise and signal strength and then pushing this NR button might feel like witchcraft when it makes a bloke driving around on the other side of the globe sound like he’s just passing your local highway intersection.

In the following sound clips you will hear both radios taking turns in 5-second chunks as if I switch forth and back between them, in some of them I will play the same bit of transmission twice, first from the one, then the other radio so you can e.g. make out differences quite precisely.

Let’s check some more distant or otherwise skinny voice signals with the Icom and what difference the NR makes on the MLite:

This is one of the most hopeless DX targets in my neck of the woods: ZKAK aka “Auckland VOLMET” in New Zealand on 13282 kHz with its mumbly, monotonous modulation. You usually only hear that it’s there but hardly understand a word unless the condx are really outstanding. The radios take 5s turns and the Icom starts, the MLite responds without NR.

Same as above with the MLite’s NR turned on and showing its limits with all the racket going on on that channel in the first half of the clip. The second half is better, but with that modulation, it’s still hopeless.

PY2ERC (from Brazil) replying to a call from an UNID station, on the Icom and the MLite without NR. The second part shows the Icom again and the same passage on the MLite with NR on.

German special call DF40ABF from 300km south received with some backscatter or something, DXing with European stations, 5-second chunks with the Icom as reference and the MLite’s NR making Europe sound as transparent as it should be.

VMW Wiluna Radio in Western Australia, with the Icom and the MLite in 5s turns, is notoriously weaker than VMC in the East, which is following next:

VMC Charleville with the Icom and an almost fully quietening MLite.

This clip has the Icom throwing its NR into the ring.  In comparison, it sounds more like it’s just painting the noise in random, darker colors, and the loss of treble range is hurtful. Icom, are you listening?

Some of the louder broadcast stations I recorded for the comparison. Please refer to the other article for more NR examples with broadcast signals; they’re just without the Icom as a reference.:

Radio Exterior de España in the 16m-band with a fairly loud and nicely consistent long path echo (around 160ms, that really went around the globe).  First, the Icom and 5s, later the MLite without NR, from there it’s the Icom again and the MLite with NR. This may be “only” Spain in 2,000km distance but the echo went more like 40,000km.

WRMI on 15770 kHz: Commercials on shortwave are a completely new thing to me, and I find this one strangely out of touch. But it had a nice groove to it to compare the same verses received on both radios, starting with the Icom

Radio New Zealand on a somewhat unstable 19m frequency, 15720 kHz. This one starts with the MLite without noise reduction, followed by the Icom, and then they take turns with the MLite and NR at “20” or so. RNZI is another station frequently coming in “long path” and “short path” simultaneously here, and it does a little in this clip.

What about the noise?

As I wrote in my first article about this radio, I found it a bit on the noisy side compared to my Belka, not really bad, but it was noticeable. Yet nothing seemed wrong with the performance of the radio; it animated me to use it a lot, and the noise reduction made it easy to forget that noise all the time. How can one radio have the same sensitivity and appear noisier than the other at the same time?

Radio France Internationale from Issoudun with fluttery fading on 16m, first the Icom and the same passages again with the MLite.

Too bad the Icom’s recordings have everything above 4kHz cut off, including all of the hiss every radio has there. But the MLite does indeed have some more noticeable hiss than the Icom in the upper mids, and the speaker characteristics make that even more prominent, not to mention that the first tests were on the whip and its preamp, adding more noise, so my first impression was a bit as if a cute little puppy wagging its tail had jumped on my lap with muddy paws. The actual difference assessed in direct comparison with the Icom shows that it’s just a bit of dust, though. I hope I have sufficiently demonstrated that any extra noise doesn’t seem to have its origin in the input stages. Of course, you’re never stuck with any extra noise; you can fix that with just minimal doses of NR:

The same, but with the MLite gently dusting off the signal with NR Level 10 or less.

VMC Australia’s 6 MHz channel

Now the IC-705 is not the very best receiver in the world and only the second best in the “portable transceiver” category, but it lives among the current top-performing ham transceivers (they’re all SDRs) and compares pretty well to more expensive radios in terms of sensitivity and noise floor. Two Russian channels have measured the MLite’s sensitivity around or better (auto-dubbed from Russian, sigh) than 0.2 microvolts, and I’m happy to confirm that this is not made up, it’s close to the Icom’s specs (0.16microvolts).

As for the noise reduction and what it can do and what it can’t – this little miracle and the good sensitivity may explain the strange attraction (not only) I seem to have to this radio: It already made listening to SW broadcast programs a thing for me again after 40 years, because hearing the stations popping out so undisturbed reminds me of ye olde happy days with comparatively insensitive and chunky radios and nothing but blowtorch transmitters filling the bands.  When the gross inverter noise at home dies off a little in the dark I can at least listen to parts of MW, 40 and 80m in full comfort and enjoy it almost more as if my QRM situation would be still on pre-pandemic levels. I found very few situations in which it wasn’t at least a bit of a help and I don’t mind having it on all the time.

25m band scan with directly recorded audio and one-third noise reduction. Antenna is a magmount CB antenna on the car roof. There’s a little demonstration of how the noise reduction can help make offset tuning a viable alternative to SSB/ECSS reception (because tuning away does not increase the noise) at the end of the video.

Barring LW/MW, I already found this radio a surprisingly competent portable on the whip, but I didn’t expect the outcome of this comparison. It may not mean much for everyone, but I adore well-made and well-performing things in general, and I was asking myself what a radio like my IC-705 could do with a noise reduction that good, and there I have my answer: It would make me love it, and that’s exactly what it does!

73, Ollie (13dka)