30 November 2008

redsun rf1201 nighttime mediumwave tuning

In a previous post, I tested daytime FM reception on my miniscule Redsun RF1201 radio. Along with my digitally-tuned Eton E5 for reference tuning, I used the RF1201 on an evening in November for some mediumwave tuning exploration. For each signal received, I've listed the callsign, frequency, and approximate distance from my location.

AM reception

KSFO 560 khz (0 miles): Strong signal but a bit noisy.

KEAR 610 khz (0 miles): Clear signal.

KNBR 680 khz (0 miles): strong signal with the needle centered on the 700 on the AM scale.

KCBS 740 khz (0 miles): Strong signal with the needle to the right of the 700 on the AM scale.

KKOH 780 khz (200 miles): Weak signal (I missed this the first time through) with the needle to the left of the 900 on the AM scale.

KGO 810 khz (0 miles): Strong signal with the tuning needle to the left of the 900 on the AM scale.

KTRB 860 khz (0 miles): Weak signal. The needle was almost centered on the 900 on the AM scale.

KNEW 910 khz (10 miles): Strong signal with the needle right of center of the 900 on the AM scale.

KWRU 940 khz (170 miles): Weak signal (I missed this the first time through) with the needle on the right edge of the 900 on the AM scale.

KKGN 960 khz (10 miles): Strong, clear signal with the needle to the right of the 900 on the AM scale.

KFWB 980 khz (360 miles): Very weak signal (not very usable) with the tuning needle to the right of the 900 on the AM scale.

KOMO 1000 khz (750 miles): Weak, noisy signal with the needle less than halfway between 900 and 1200 on the AM scale.

KIQI 1010 khz (0 miles): Average signal with the needle less than halfway between 900 and 1200 on the AM scale.

KTCT 1050 khz (20 miles): Strong, clear signal with the needle more than halfway between 900 and 1200 on the AM scale.

??? 1090 khz: Extremely weak, and impossible to isolate from the adjacent signal on 1100. The needle was just left of the 1200 on the AM scale.

KFAX 1100 khz (0 miles): Strong, mostly clear signal with the needle over the 1 in the 1200 on the AM scale.

KHTK 1140 khz (70 miles): Average signal with the needle between the 1 and the 2 in the 1200 on the AM scale.

KLOK 1170 khz (45 miles): Weak, noisy signal with the needle almost centered on the 1200 on the AM scale.

KSFB 1260 (0 miles): Strong, clear signal with the needle on the last digit in the 1200 on the AM scale.

KMKY 1310 khz (10 miles): Loud, strong, clear signal with the needle to the right of the 1200 on the AM scale.

KZSF 1370 khz (45 miles): Weak, noisy signal with the needle centered between the 1200 and the 1620 on the AM scale.

KVTO 1400 khz (10 miles): Strong, clear signal with the needle to the left of the 1620 on the AM scale.

KEST 1450 khz (0 miles): Average, clear signal with the needle on the 1 in the 1620 on the AM scale.

KSJX 1500 khz (45 miles): Weak, noisy signal with the needle on the 6 in the 1620 on the AM scale.

KFBK 1530 khz (70 miles): Weak signal with the needle centered on the 1620 on the AM scale.

KMPC 1540 khz (360 miles): "Radio Korea... Los Angeles." Really weak signal; sounded choppy due to a stronger signal on the adjacent channel (1550).

KYCY 1550 khz (0 miles): Strong signal with the needle just right of center on the 1620 on the AM scale.

Unfortunately, 1550 was the highest signal I could get reliably, so I was unable to really test the upper bounds of the AM band on this radio.

In a few cases, this little radio picked up mediumwave broadcasts from hundreds of miles away. However, weak signals that are adjacent to stronger signals will often be unusable.

22 November 2008

14 November 2008

interesting email from cri

A few days ago, I got an interesting email from China Radio International:
How are you? We haven't heard from you for a long time.

We wonder whether you can do us a favor helping to monitor the 1190AM(WBIS), the broadcast time is 1400-1500(Mon.-Fri.) Local time. Thanks in advance.

Looking forward to your reply.

Best wishes,

Yours sincerely,
YingLian
English Service
China Radio International
http://english.cri.cn/
I have written to CRI via email several times with shortwave reception reports and requests for magazine mailings. So, they have my postal address. I'm kind of curious why they would ask me to monitor a mediumwave station that's about 2,500 miles (4,023 km) from my location.

10 November 2008

redsun rf1201 daytime fm tuning

On a day in late October 2008, I used my Redsun RF1201 for some tuning adventures. My digitally-tuned Kaito KA1102 was used for reference. I also used my Tecsun R9012 for tuning and audio comparisons with the Redsun RF1201.

The Redsun RF1201 is a very attractive pocket radio. The tuning scale is very legible, and the white printing on the dark gray enclosure provides nice contrast. The power switch, band switch, volume dial, and tuning knob all function well and illustrate the radio's solid construction. The folding radio prop on the back actually snaps into place when deployed.

For each signal received, I've listed the callsign, frequency, and approximate distance from my location.

FM broadcasting reception

KQED 88.5 mhz (0 miles): Although this is a strong, local signal, it took a lot of fine-tuning to achieve a clean signal. The needle was approximately centered over the 90 on the FM scale.

KUSF 90.3 mhz (0 miles): The tuning needle was about halfway between the 90 and 94 on the FM scale, and I got a perfectly clear reception here with ease.

KNGY 92.7 mhz (10 miles): With the tuning needle touching the right edge of the 90 on the FM scale, I found this station but I also heard an image of KOIT 96.5 mhz. Because of the image, I was unable to get a clear signal of KNGY at first. However, I kept tuning and found a clear signal for KNGY with the needle centered on the 94 on the FM scale.

KOIT 96.5 mhz (0 miles): I got a clear signal with the tuning needle on the left side of the 98 on the FM scale.

KLLC 97.3 mhz (0 miles): With a slight movement from the 96.5 mhz station, I picked this one up easily.

KISQ 98.1 mhz (0 miles): It wasn't possible for me to isolate a clear signal for this station on the RF1201. The same problem was exhibited on the Tecsun. I contacted this station within the past couple of years to tell them about my reception problems. They replied and said that they were working on upgrading their equipment.

KSOL 98.9 mhz (0 miles): This Spanish-language station came in pretty clearly with the tuning needle about halfway between 98 and 102 on the FM scale.

KDFC 102.1 mhz (0 miles): This station came in very clearly with the needle almost centered on the 102 on the FM scale.

KKSF 103.7 mhz (0 miles): This station keeps smooth jazz alive in the San Francisco bay area. With the needle on the right side of the 102 on the FM scale, this station came in clearly.

KFOG 104.5 mhz (0 miles): With the needle to the right of the 102 on the FM scale, this station came in clearly.

KVVF 105.7 mhz (40 miles): This Spanish-language music station from Santa Clara came in with some noise.

KCBS 106.9 mhz (0 miles): The local all-news station that just began broadcasting on this frequency came in clearly with the needle on the left half of the 108 on the FM scale.

Audio quality

While receiving KNGY, I compared the audio quality of the speaker with a Tecsun R9012. The Tecsun had a sound that I would describe as hollow, while the Redsun unit had a clearer, fuller, brighter tone. While the Tecsun sounds fine for talk radio, I prefer the Redsun's speaker for listening to music.

Another way I tested the clarity issue was to tune the Redsun and Tecsun radios to the same station, turn the volume up a bit (on one radio at a time), and go to the other end of the room to listen. The Redsun was much easier to understand.

KDFC is a classical music station. Although I don't listen to classical music much, it is useful for audio testing. Classical music is comprised of pure recordings of well-known instruments, so knowing how these instruments typically sound is an effective reference. The RF1201 didn't hold up so well here because of the limited frequency response of the built-in speaker. More lower frequencies would have helped here.

Sibilance was not a problem when tuned to a clear broadcast. Sometimes, even a clear broadcast on some radios can sound distorted when emitting the "s" sound, producing what sounds like distortion. I would speculate that this is caused by inferior audio path components in the radio. The RF1201 does not noticeably demonstrate this problem.