PL-380 vs RQ-SW20 near strong signals


pianoplayer88key
 

Hi all. I own a PL-380, and have been a bit disappointed in how it performs near strong signals, especially considering the glowing reviews I had read. So, I decided to record some tests, and some comparisons between that and my previous radio, a Panasonic RQ-SW20 which has selectivity that's probably comparable to the Sony SRF-M37W, if not a bit worse.

For one of the tests, I checked reception of some weaker stations inside a stationary vehicle (to reduce overall signal strength, and reduce the RSSI on blank channels from local strong stations). I generated the strong signal by tuning an old (1980s or older) Zenith AM radio I have to a few particular frequencies to generate a local oscillator signal 455kHz above where the Zenith was tuned.

First - PL-380 tests, tuning Zenith's LO (local oscillator) to particular channels and comparing LO off vs LO on. For all tests, the PL-380 was in the 1kHz bandwidth mode.


Zenith LO = 1000 kHz

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1030%20XESDD%20-%20LO=1000%5EJ%20PL-380%20-%20off%5EJ%20on.mp3
1030 XESDD (LO to XESDD = 30 kHz)
LO off: 26,25 (dBu RSSI, dB SNR)
LO on: 50,00 (start 0:09.5, weak XESDD)

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1040%20KURS%20-%20LO=1000%5EJ%20PL-380%20-%20off%5EJ%20on%5EJ%20off.mp3
1040 KURS (LO to KURS = 40 kHz)
LO off: 34,25
LO on: 50,00 (start 0:10, weak KURS, turn off @ 0:25)

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1070%20KNX%20-%20LO=1000%5EJ%20PL-380%20-%20off%5EJ%20on%5EJ%20off.mp3
1070 KNX (LO to KNX = 70 kHz)
LO off: 28,25
LO on: 50,03 (start 0:25, almost no trace of KNX, turn off @ 0:42)

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1130%20KSDO%20-%20LO=1000%5EJ%20PL-380%20-%20off%5EJ%20on.mp3
1130 KSDO (LO to KSDO = 130 kHz)
LO off: 57,25
LO on: 51,25 (start 0:11.5, some noise behind KSDO)


Zenith LO = 1290 kHz

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1170%20KCBQ%20-%20LO=1290%5EJ%20PL-380%20-%20off%5EJ%20on.mp3
1170 KCBQ (KCBQ to LO = 120 kHz)
LO off: 61,25
LO on: 58,25 (start 0:21.5, some noise behind KCBQ)

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1270%20XEAZ%20-%20LO=1290%5EJ%20PL-380%20-%20off%5EJ%20on.mp3
1270 XEAZ (XEAZ to LO = 20 kHz)
LO off: 31,25
LO on: 50,00 (start 0:24, very weak XEAZ)

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1280%20KFRN%20-%20LO=1290%5EJ%20PL-380%20-%20off%5EJ%20on.mp3
1280 KFRN (KFRN to LO = 10 kHz)
LO off: 20,05
LO on: 50,01 (start 0:37, 10kHz het, no KFRN)

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1310%20XEC%20-%20LO=1290%5EJ%20PL-380%20-%20off%5EJ%20on.mp3
1310 XEC (LO to XEC = 20 kHz)
LO off: 23,21
LO on: 50,00 (start 0:20, no XEC)

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1360%20KLSD%20-%20LO=1290%5EJ%20PL-380%20-%20off%5EJ%20on.mp3
1360 KLSD (LO to KLSD = 70 kHz)
LO off: 50,25
LO on: 50,11 (start 0:13.5, noisy KLSD)

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1390%20XEKT%20-%20LO=1290%5EJ%20PL-380%20-%20off%5EJ%20on.mp3
1390 XEKT (LO to XEKT = 100 kHz)
LO off: 26,25
LO on: 50,18 (start 0:19.5, very weak XEKT)

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1450%20KFSD%20-%20LO=1290%5EJ%20PL-380%20-%20off%5EJ%20on.mp3
1450 KFSD (LO to KFSD = 160 kHz)
LO off: 17,04
LO on: 50,01 (start 0:33, no KFSD)


Zenith LO = 1500 kHz

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1550%20XEBG%20-%20LO=1500%5EJ%20PL-380%20-%20off%5EJ%20on.mp3
1550 XEBG (LO to XEBG = 50 kHz)
LO off: 15,12 (sometimes indicates up to 15,18)
LO on: 50,00 (start 0:20, no XEBG)



Then, I did some LO off/on comparisons between the Tecsun PL-380 and the Panasonic RQ-SW20. As noted above, the RQ-SW20's selectivity at best matches the Sony SRF-M37W, and is likely a bit worse.

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1070%20KNX%20-%20LO=1150%5EJ%20PL-380%20vs%20RQ-SW20.mp3
1070 KNX (LO = 1150 kHz, difference = 80 kHz)
PL-380:
LO off: 31,25
LO on: 50,23 (start 0:12, weak KNX)
RQ-SW20:
LO off: start 0:57.5
LO on: can't tell any noticeable difference, heard a little click at 1:19.5 or which was probably me turning the LO on)

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1280%20KFRN%20-%20LO=1150%5EJ%20PL-380%20vs%20RQ-SW20.mp3
1280 KFRN (LO = 1150 kHz, difference = 130 kHz)
PL-380:
LO off: 17,07
LO on: 50,00 (start 0:31, no KFRN)
RQ-SW20:
LO off: start 0:55.5
LO on: start 1:05, slight change in noise, KFRN maybe slightly weaker but can still be heard unlike with the PL-380

http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/1550%20XEBG%20-%20LO=1400%5EJ%20PL-380%20vs%20RQ-SW20.mp3
1550 XEBG (LO = 1400 kHz, difference = 150 kHz, slight interference from Zoom H2 that was being used to record)
PL-380:
LO off: 15,12 (as I said above, sometimes indicates up to 15,18)
LO on: 50,00 (start 0:26.5, no XEBG)
RQ-SW20:
LO off: start 1:09
LO on: start 1:25, slight change in noise but can still hear signal just about as well as with LO off



Finally, I took the radios outside (out of the truck), set the Zenith AM radio aside, and ran my second test. I tuned the Select-A-Tenna to 1170 kHz, my strongest local AM station, and oriented to face the station's transmitter. I then put the radios next to the SAT and did bandscans from 1170 to 1710, then down from 1170 to 950 on the RQ-SW20 and to 790 on the PL-380.

PL-380 scan: (beep was turned on so you can hear when the radio is tuned, normally I have it turned off)
http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/SAT%20tuned%20%5E0%20facing%201170%5EJ%20PL-380%20scan%2010k%201170-1710%5EJ%201170-790.mp3
not all frequencies will be listed below. occasional timestamps will be listed to help you get your bearings
first, scan from 1170 up to 1710
1170 - 63,25 - KCBQ
1180 - 50,00 - slight splatter from KCBQ
1210 - 50,00 - weak KPRZ (when not using the SAT to boost KCBQ, KPRZ is a nearly noise-free 52-54dBu signal with audio basically as loud as a 63+dBu signal)
1220 - 49,00
1240 - 49,14 - KNSN
1260 - 49,00 - weak image of KCBQ
1270 - 49,20 - XEAZ - 1:43
1280 - 49,00 - weak KFRN
1310 - 49,00 - semi-weak XEC - 2:22
1350 - 47,00
1360 - 51,25 - KLSD (some noise) - 2:58
1370 - 47,00
1390 - 47,00 - semi-weak XEKT
1420 - 47,23 - semi-noisy XEXX - 3:43
1430 - 49,00
1440 - 45,00
1450 - 45,00 - weak KFSD - 4:15
1470 - 53,25 - XERCN - 4:35.5
1480 - 43,00
1550 - 43,00 - semi-weak XEBG - 5:35
1560 - 41,00
1580 - 41,00 - weak KBLA - 6:03
1600 - 41,00 - weak KAHZ (? - Pomona)
1620 - 41,00 - weak WNSB415 San Ysidro TIS - 6:42
1630 - 48,25 - XEUT
1650 - 41,00 - weak KFOX
1670 - 39,00 - semi-weak KHPY
1700 - 47,25 - XEPE - 8:02.5
next, scan from 1170 down to 790
1160 - 50,00 - slight KCBQ splatter
1140 - 50,00 - moderate KSDO splatter
1130 - 63,25 - KSDO - 8:58.5
1120 - 49,00 - moderate KSDO splatter
1110 - 49,00 - weak KDIS
1090 - 50,25 - slightly noisy XEPRS
1070 - 49,14 - semi-weak KNX - 9:51
1040 - 49,20 - semi-noisy KURS
1030 - 49,21 - semi-noisy XESDD
1010 - 47,00
1000 - 45,22 - KCEO - 10:40.5
990 - 45,00
980 - 45,00 - weak KFWB
970 - 45,00 - very weak KNWZ - 11:20
960 - 43,00
950 - 50,25 - XEKAM
930 - 43,00 - weak KHJ - 11:54
910 - 63,25 - KECR (slight splatter on 920)
900 - 41,00 - slight KECR splatter
890 - 41,00
870 - 41,00 - weak KRLA
860 - 54,25 - XEMO - 12:54
850 - 39,00
830 - 39,19 - semi-weak KLAA
810 - 37,00
800 - 53,25 - XESPN (slight splatter on 810 & 790) - 13:43
790 - 37,00 - weak KABC, slight XESPN splatter, stopped here


RQ-SW20 scan:
http://cid-6bdd1917662288cb.office.live.com/self.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20near%20strong%20signals%20-%202010-06-17/SAT%20tuned%20%5E0%20facing%201170%5EJ%20RQ-SW20%20scan%2010k%201170-1710%5EJ%201170-950.mp3
as above, not all frequencies are listed, some timestamps are given
first, scan from 1170 to 1710:
1170 - strong KCBQ signal
1210 - KPRZ mixing under KCBQ, maybe slight mix of 1130 KSDO - 1:02
1240 - KNSN mixing with KCBQ
1260 - last frequency on which tuning indicator is lit - 1:36.5
1270 - XEAZ under KCBQ (XEAZ probably semi-attenuated due to SAT antenna pattern)
1310 - XEC over KCBQ - 2:11.5
1360 - strong KLSD - 2:37
1390 - XEKT
1420 - XEXX
1440 - image of KCBQ - 3:11.5
1450 - KFSD
1470 - strong XERCN - 3:30.5
1510 - weak KSPA mixing with weak KCBQ - 3:49
1550 - XEBG
1580 - weak KBLA - 4:21.5
1620 - WNSB415 under 1630 XEUT
1630 - XEUT
1650 - KFOX
1670 - weak KHPY - 5:12.5
1700 - strong XEPE
now, scan down from 1170 to 950:
1130 - KSDO over KCBQ - 6:02
1090 - XEPRS (KCBQ slightly in background maybe)
1070 - KNX - 6:35
1040 - KURS
1030 - XESDD - 6:50
1000 - KCEO
980 - weak KFWB - 7:14
950 - strong XEKAM, stopped here


Ok, so the PL-380 is SUPPOSED to have better selectivity than other radios. However, I've noticed that when faced with a very strong signal (one that spreads 50,00 readings on the PL-380 on a portion of the band, or splatters & lights the tuning LED several channels each way on the RQ-SW20) somewhere on the dial (it doesn't even have to be within 10 or 20kHz)... the Panasonic RQ-SW20, in spite of having MUCH worse selectivity than the PL-380 (and very likely worse than the Sony SRF-M37W, and being about 15dB less sensitive overall than the PL-380, actually is able to pull in stations from about 100-200kHz away from the strong local. However, the PL-380, when faced with that same strong signal, usually can't even get a trace. As noted in some of the LO off/on comparisons above, if the strong signal wasn't there, that non-existant signal would actually become one that would be moderately comfortable to listen to in some cases!

So... WHY is it that a radio with selectivity WORSE than the Sony SRF-M37W actually BEATS the PL-380 when listening to a semi-weak station 100-150kHz away from the very strong local signal?

Also, there are some stations on the PL-380 that I think would have a fairly strong signal, if it wasn't for strong locals 20 and 60 kHz above it that are putting about 39dBu or so on 1110, for one example. In other cases some stations that would otherwise be weak, but listenable (for example, may read 15,18 or so) are buried under the general 30,00 noise floor across most of the band at my location. What gives? :(

One of my reasons for getting the PL-380 was to help alleviate these problems I've been having, among them being having a radio not sensitive enough to hear weak signals I wanted to hear, and not selective enough to separate nearby strong ones. It seems that while the PL-380 is somewhat more selective than my RQ-SW20, the sensitivity suffers even more than the SW20 when faced with a strong signal. I will admit that within a few channels the PL-380 is generally better, but I really was hoping to get a much better signal on 1110 KDIS, for example. :(

Any ideas of another model I should try, preferably with a vertical orientation, multiple bandwidths, no soft-mute, etc, that will fit in my pants pocket? :(

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