Tag Archives: Japanese radio

Video blog episode 007

I’m still working on the second part of the 6-meter Yagi video series, so I decided to show an example of trans-Pacific AM broadcast band reception using the RTL-SDR based AM BCB receiver detailed in Episode 006.  This was from an SDR recording on the morning of September 21st, 2016 and was a pretty good session.  Unfortunately, the audio was rather uneven because I was trying for the first time to “internally” record my laptop screen instead of shooting with the video camera.  That part worked great, but the audio didn’t go quite as well.  Still, this gives a nice flavor for what I have been able to from Arizona with the RTL-SDR based AM BCB receiver, and the Conti Superloop antenna featured in earlier videos.

Log: AM broadcast band, September 30th, excellent trans-Pacific reception

Between work and being sick for a week, I haven’t had a chance to post anything about the current trans-Pacific reception season. But, it has been a pretty good one, and this day provided the best audio of the season.
Continue reading

Log: AM broadcast band, March 10th, good trans-pacific reception

Although I was making an SDR recording, I also worked this one live. Activity was already in progress when I started a little before 1200 UT (5am MST), and this turned into quite good reception. It started out mostly on the low-end of the band, but the upper-end kicked in by around 1225 UT. The best activity was during the 12UT hour, with a decrease near the end of the hour. Some stations were doing pretty well after 13UT, including 1566 HLAZ out of Korea, but in general activity wasn’t very good then. Activity totally fizzled out by local sunrise at 1347 UT (6:47am). The real surprise was the strength of 1134, presumably HLKZ out of Korea, producing brief bursts of fair audio. First a summary, then some audio samples. Continue reading

Log: AM BCB, September 20th, more trans-Pacific reception

(7’x24′ Conti superloop pointed 320 degrees, RTL-SDR dongle with upconverter, coverage only up to around 1400kHz due to filtering)

This was an interesting morning as there was a strong geomagnetic storm overnight, although that usually doesn’t affect things this far south. The early peak just after Japanese sunset was decent with weak audio from 747 and 774 kHz already by 0913UT (2:13am MST). That continued off and on for another half-hour. The main peak before local sunrise started shortly after 12UT. I didn’t get the large number of carriers or as many frequencies with audio, but 774-JOUB (Akita, Japan, 500kW) delivered the best audio I’ve had this month.

1204UT – 747 audio being persistent and almost intelligible
This was followed by a fairly long period of only carriers
1242UT – 774 picked up a lot, and up to medium audio at 1243UT
1248UT – 774 medium audio again, a man talking
1258UT – 774 medium-good audio again, a man still talking, into the TOH 3+1 pips
1300UT – 774 a bit of a fade out, but stronger again for a bit

Here is a longish recording from 774 starting at 12:58:00UT. Just for perspective, the recording starts out before the audio became intelligible, but quickly rises up to a nice level. It fades out again after the TOH pips, but the recording continues and the signal comes back for a bit before dropping below intelligibility for good. If you don’t want to listen to the whole thing, the best audio is from about 0:30-2:00 in the file:

There were decent carriers at times on 594, 693, 828, 972, and 1053, but not much more than that.

Log: AM BCB, September 18th, strong trans-Pacific reception

(7’x24′ Conti superloop pointed 320 degrees, RTL-SDR dongle with upconverter, coverage up to around 1400kHz)

September has been quite good for trans-Pacific (TP) reception, and this was a particularly good morning. Although I never got any great audio, I had a lot of it for this location, and a plethora of carriers. The main action started after 1215UT (5:15am MST) and lasted until near local sunrise at 1314UT. Overall the best TP session out of 9 this month.

English lessons (not quite intelligible) from NHK peaking on 747 at 1232UT and on 774 peaking at 1220UT. 972-HLCA very briefly had the best signal of the morning at 1301UT. Also faint audio from 693 (including the 1300UT time pips), 828, 1053 (both the jammer and the jammed), 1116, 1134, and 1296. Another 40 9kHz frequencies with medium to strong carriers.

20-minute breakdowns:

Weak audio:
747 at 1231-1234 (English lessons)
774 at 1217-1222UT and 1226UT (English lessons; almost intelligible at 1220 through KKOB splatter)
972 at 1230-1231UT and 1234UT (very faint speech)
1053 at 1217-1218UT and 1226UT (speaking or singing?)
Strong carrier: 828, 972, 1134
Medium carrier: 594, 693, 747, 945, 954, 1044, 1089, 1116, 1143, 1323

Weak audio: 693 at 1254UT
747 at 1236UT
774 at 1243-1246UT and 1249-1253 UT (English lessons)
828 at 1252UT
972 at 1235-1237UT, 1243-1245UT, and 1254UT (music)
1053 at 1249UT and 1253UT (unsure of content)
1296 at 1254UT (unsure of content)
Strong carrier: 594, 603, 693, 1134, 1224, 1242, 1314
Medium carrier: 657, 729, 828, 873, 954, 1008, 1044, 1089, 1098, 1116, 1179, 1197, 1269, 1278, 1287, 1359, 1386, 1404, 1422

Medium audio: 972 at 1301UT (voice into music; additional weak audio at times)
Weak audio:
693 at 1300UT (heard 3+1 pips and then talking)
747 at 1255UT (very faint talking)
774 during much of the period (intermittent faint audio and last TOH pip, best at 1303)
1053 at 1259UT (jammer?)
1116 at 1259UT (brief very faint speech)
1134 at 1257-1258UT (faint female speech, then local 1130 went to full power)
Strong carrier: 594, 603, 693, 828, 1008, 1107, 1116, 1134, 1224, 1278, 1296, 1314
Medium carrier: 558, 612, 657, 666, 786, 864, 872, 893, 963, 954, 963, 1008, 1017, 1044, 1098, 1143, 1179, 1197, 1206, 1242, 1287, 1323, 1332, 1359, 1377, 1386, 1404, 1422 (the latter two even though my low pass filter for 1450/1490 is really kicking in by this point)


Log: AM BCB, September 15th, trans-Pacific reception

I’ve done SDR recordings on about half of the mornings this month with my 7’x24′ Conti superloop (corner-fed, corner terminated broadband loop), RTL-SDR dongle, and Ham It Up upconverter. This morning was the best so far, with audio from several stations, and fairly decent audio from 972 kHz out of Korea. It also exhibited a pattern I’ve been seeing where I get good Japanese reception shortly after their sunset, and another enhancement shortly before my sunrise. The latter is common, but the former has been quite noticeable this month. In the following log, I list all the 9kHz frequencies where I had at least a medium carrier within 20-minute intervals from 0935-1315UT (2:35-6:15am MST). Signals dramatically weakened around local sunrise of 1312UT (6:12am MST). My frequency coverage only went up to 1400 kHz due to filtering to remove strong locals at 1450 and 1490.

First, for the IRCA mailing list members who have already seen this log, here is the audio sample at 12:57:30UT from 972-HLCA with some splatter from 970:

And, the 20-minute log:
Weak audio: 747 and 774 around 0936-0938
Strong carriers: 594, 693
Medium carriers: 828, 1053, 1134

Strong carriers: 693, 774, 1053
Medium carriers: 594, 747, 828, 1134

Medium carriers: 594, 693, 747, 774, 828

Medium carriers: 693, 774, 828

Medium carriers: 594, 693, 774, 828, 1053

Medium carriers: 693, 774, 828, 1053

Strong carriers: 774
Medium carriers: 693, 828, 972, 1053, 1134

Weak audio: 972 from 1215-1219UT
Strong carriers: 774, 828
Medium carriers: 747, 1053, 1134

Medium audio: 972 from 1247-1250UT (other bursts of weak audio)
Weak audio: 774 at 1251UT, 828 at 1239UT
Strong carriers: 747, 972 (near audio at 1254UT)

Medium audio: 972 from 1255-1301UT, quite decent around 1258UT, mix of talking and music
Weak audio: 774 at 1258UT, 972 continuing until 1304UT
Strong carriers: 693, 1053
Medium carriers: 594, 747, 828, 864, 936, 945, 954, 963, 1008, 1044

A few lingering medium carriers after local sunset, inc. 828, 974

Log: AM BCB, March 12th, trans-Pacific reception

AM broadcast band DXing with:
Antenna 1: 6-foot diagonal wooden-frame tuned loop
Antenna 2: 23-foot “fishing rod” vertical with MFJ-1020C amplified pre-selector
Combiner: Quantum Phaser
Receiver: RTL-SDR dongle, Ham It Up upconverter into laptop

This was mostly a low-band morning, and some of the best conditions I’ve had this year. It didn’t get off to a particular early start, but after 5am MST (12UT), things were hopping.

I finally got intelligible audio from NHK Radio 2 during their weekday English lessons (late in the evening in their time zone). I’m not sure if “Were you taken to the hospital?” is necessarily a common phrase, but that’s the first English audio I’ve received on the AM band from overseas at 5:22am MST (1222UT):

Here’s some more typical Japanese language fare an hour later:

Most of the rest of the audio is more about getting audio at all, rather than sound quality. I picked up two presumed Korean stations, 972-HLCA (new) and 1566-HLAZ. I caught some music into conversation on the former at 6:04am (1304UT), just enough to think it was Korean language:

I’ve had much better audio on 1566 earlier this month, but for completeness, here is a sample from 6:30am (1330UT):

NHK 2 has other transmitters besides 774 kHz, and I was able to finally get some weak audio on 747-JOIB. (Presumably, of course, since I didn’t hear an identification, but it is highly likely.) Here is a sample from 6:23am (1323UT):

I also picked up the presumed China National Radio station on 1593 kHz, with just enough signal to produce weak audio at 6:30am (1330UT):

I also could see carriers on the SDR display on a bunch of frequencies that were too weak to produce audio, including: 693, 738, 765, 828, 864, 873, 945, 963, 981, 1422, 1503, 1521, and 1557. There may have been others, but with my tuned antenna system, I can only peak up a limited range of frequencies at any given time. Thus, even going through the SDR recordings, I can’t check the entire band.