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.

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