Tecsun PL360 review(given)

Tescun with its PL360 keeps its tradition on making radios with nice specifications such as using preset sleep time from radio’s power on , analogue volume and huge audio . This radio even exceeds these specification by adding a DSP IC circuit for all stages and keeping analog volume control !

This is my second to last radio bought on August 11 from the local (Greek) market after making an internet survey . The radio costs Eu45 (in HK is priced $45 ) plus Eu10 for shipping (this is quite much considering the distance between my city and the store is less than 200km . Compare the shipment for Degen 1126 from HK with only Eu15! )

The box set consists of the radio , a loopstick for enhancing MW reception , earphones , a flexible antenna wire for SW and FM and a handbag. on the rear of the radio there is a belt clip . Its size a nearly of a remote control as noticed by N9WEO but is quite thicker than my remote controls.

This radio is use sparingly mostly for field monitoring .

Here are several pictures of the radio

This is the radio with all its accessories inside the box The loopstick antenna is shown in the upper left part

The loop stick . The suposed frequancy range is 150-1700 kHz It has a gain of ca 10 db

The provided soft antenna with clip for radio's telescopic antena

Radio's display . battery level is shown at left top corner , alarm or temperature on the top right and time

Radio's keyboard ETM is easy tuning mode , VF is frequency mode , Sw buttons lead to shortwave sub-bands (19 m , 13m, 11 m etc )

The power charging socket (typical mini USB D type )and the thumbwheel xscnning

The belt clip as shown in the rear of the radio

The battery compartment . Instead of 2 or 4 batteries , it uses 3 as in 1102 !!

Another viw of the display

The sockets: socket for loop stick and earphone socket

Some of the most interesting features of this radio:

The DSP technology

As noticed by N9EWO and radio time traveler this radio family uses the Silicon labs Si4734 receiver chip. Please read these sites for more info on the end of this part

The dbu and db S/N readout

Although the 1126 and other models of the Degen 11xx family use the same IC, most of the Tecsun 3xx family show also the dbu and the dsb S/N readouts . I thought that this indication shows the signal strength across the built in antenns . However on the RTT site the foloweinh is noticed:: (http://radio-timetraveller.blogspot.gr/2010/06/review-of-tecsun-pl-380-dsp-receiver.html will be shown afterwards as RTT ) Please dont forget that the series PL3xx uses the same receiver DSP chip:

“RSSI indications, as displayed on the PL-380, can range from 15 to 63 dBµV. Per Scott Willingham, one of the Si4734's designers, "The RSSI readings are referred to the pins of the chip, which are the inputs to the LNA. In the Tecsun radios operating in the MW band, this is also the voltage across the loopstick. In SW bands, the Tecsun ULRs use a preamp/LNA on the circuit board between the whip antenna and the Si4734. In that case, the RSSI readings reflect the signal at the output of Tecsun's external LNA."

Displayed SNR indications can range from 0 to 25 dB. About SNR measurements, Scott Willingham related that, "The SNR figure is calculated by a proprietary DSP algorithm, and neither the RSSI nor audio output directly play a role. The input to the algorithm is the filtered IF signal before audio demodulation. It is really more of a carrier-to-noise ratio than directly an audio noise measurement. Obviously, in AM it is bounded between 0 and 25 dB. The motive for computing and providing the number comes from implementing better station search capabilities; the display is just a nice byproduct."

Thus the digital readout is somehow different to what I expected.

Temperature indicator/frequency band : this is is set and displayed by radio’s power off and depe4nds to region selected. Set to Americas temp in F is shown covering 500-1700 kHz . Set to Europe degs in C are shown and covers LF and MF band (150-1620kHz )

Plenty of memories: Total of 450 : 100 for FM , 100 for MW and 250 for SW

Several methods of scanning : ETS (easy tuning by scanning the band ) ATS (auto tune storage ), manual wheel scan . A scanning on L+MF band is achieved in ca 35-40 seconds. And all memories can be accessed by the (frequency) thumbwheel

USB jack for battery charging !!

Battery compartment : It uses 4 AA batteries , If batteries are removed , the indications are kept for a while.I found that more than 10 hours can be used for the above shown alkaline batteries

This article is not exactly a review of this radio. It is a comparative test between the PL360 and Degen’s 1126 and 1102 If you like to look for a review you can look at http://n9ewo.angelfire.com/pl360.html and this http://radio-timetraveller.blogspot.gr/2010/06/review-of-tecsun-pl-380-dsp-receiver.html for some more insight (though it refers to pl380)

MW/LW performance observations :

· In MW I found that PL360 has better audio, than 1126 due to wider bandwidth. It is little bassier to DE1102 if the filter is set to narrowband (so I suppose it has a 4 kHz bandwidth ) .

· Dropout / signal chopping (per N9EWO;s page as noticed above ) or soft mute ( per RTT )as it is defined (ie the sudden drop of audio below DSP circuitry’s threshold ) is more smooth than 1126 that has sudden drops.

· The fine step is 1 khz and span is 150 to 1620 kHz for European bands or 520 -1700 kHz for American band. I prefer setting it to American band in order to listen to Greek pirates.

· On LW I didn’t find any station even with the loopstick plugged. There were only several carriers or TTY signals on 300-400 kHz

· Sensitivity is nearly the ‘same’ between DE1126 and PL360 . There is some degradation above 1400 kHz. I m not sure if this caused by a sudden circuitry overloading after I tested with the Tecsun loop

· The internal noise level is quite lower than of 1126 but is still relatively high .

· The S/N indication refreshes every 4 seconds

· The loopstick enhances the signal on MW by 10-15 db across the band . On the appendix the table 3 shows comparative results between the inner loop ,the loopstick and the AN200 antenna , connected or inductively coupled inside the loop (this offers the highest gain among all configurations )

· During listening I found several frequencies blocked by internal superhets or possibly buzzers. Hets have been found on 666 , 729 kHz blocking reception of stations of ERA from Athens

Notice: audio has been tested via two Carrefour ear buds . ‘Sensitivity’ has been checked by my idea of setting both radio’s to a strong station, adjusting both radios for the same audio level using one bud per radio per ear ,[sop setting for a middle point] , and finally checking the position of audio in other frequencies , from preferably poor signals. This configuration can be used also for listening to a quasi stereo (diversity stereo ) !

Shortwave

· The same audio performance can be said for all 3 radios . The ‘sensitivity’ (using my headphone technique ) is nearly the same for both DSP radios except above 11 MHz where PL360 produces better audio . Degen DE 1102 outperforms both radios .

· The radio is not affected by overloads if long antennas are used. Our nearby radio station Era Thessaloniki on 1179 kHz overload s De1126 with its power of 50 kW from a distance of 10 km (it is not EIRP )

· The soft mute here is more intense on DE1126 than on MF making reception nearly useless. . PL360 has some soft mute but is not so annoying . And though they use the same DSP IC !

FM:

In FM the things are different between 1126/360 and 1102 . Both DSP radios offer a very high selectivity. This nearby frequency separation is excellent and shines over all other analogue radios from Degen and Tecsun I have, even from my Yupiteru scanner . PL660 has quite narrow bandwidth and follows the adjacent station separation of both DSP radios

As for example in my overcrowded FM band in Retziki I can listen to R Asteras from Imathia (prefecture of Verria, 40 km distance )on 90.6mHz that otherwise can’t be heard with any other radio except if I try to chase the best signal . With these radios reception is not only easier but free of interference

· The only minus for both radios is the relatively low sensitivity comparing to 1102

· DE1126 loses its stereo if signal is relatively low. ‘Signals’ of more than 15-20 dbu are received in stereo on PL360

· The S meter updates every second

· The earphones cord can be used as antenna if telescopic antenna is folded

· Audio is richer than 1126 , and is close to 1102 though a bit bassier

· Frequency step is 10 kHz (1126 is 100khz )

Audio

DE1126 has a digital volume control of a total 32 steps . PL 360 has an analog control but maximum volume is stronger than DE1126 or 1102. The output earphone volume is nearly the same from the built in speaker. This is in contrast to what’s happening with PL200 and PL500 These radios seem to have a direct output thus offering very high earphone audio. On same volume the internal speaker is quite low.

Provided soft antenna

The provided antenna is a very thin wire with modest shortwave reception

But using a same length #14 stranded wire , signals are much stronger . The signal readout shows levels of 10-15 db higher in the dbu meter (did not compare them together )

Using the AN200 passive tuned MW loop comparisons

· Radio’s internal loop is quite small , but enough to receive the most usual daytime stations (666, 729 with 50kW from Athens , 810 from Skopie )

· This loop antenna can be used with 360 by two ways : either by connecting an audio cable jumper of 1.9 mm (preferably stereo jumper as others advise) or inductively coupled .

· The inductive coupling, correctly tuned, increases signals by 25-30 db as it is shown on the table 3

· I am not 100% sure if inductive coupling can cause any damage to any radio. Once 1102 after used this way its wide filter lost its sensitivity . PL360 after doing this experiment shown degradation above 1400 kHz

· As far as I tested , De1126 is not affected by the loop . IN contrast to it PL360 is normally effected inductively by the loop azs most other radios

MY verdict :

This radio is a surprise to me! It is much better than DE1126 (though not as 1102 )in terms of soft mute, audio fidelity, volume , band scan (1 khz instead of 5 )and ergonomics.

I could like to see in this radio :

I could prefer if temperature could be displayed separately from American /European bands and still include LW !

Temperature readout separated from American or Europen steps in MW

The usage of LSB abd USB!

To have a separate memory for radio recording (as in 1126 )

Appendix

Table 1 PL360 vs DE1126 diversity ‘stereo’ on SW . Sensitivity check using the technique mentioned on notice on MW paragraph .

1 heard only on 1126

9 heard only on PL360

Feq Sgl

4780 3

4800 5

4905 3

5820 fluttering in both

5960 5

9310 4

9540 5

11530 6

11565 7

13570 7

13590 9

15135 7

Table 2

PL360 vs 1102 using diversity technique as mentioned above (1=PL360 9= De1102 )

4975 9

4950 7

5855 8

7070 7

9310 7

11530 7

Table 3 Comparative ‘signal strength’ using various configurations

Signals here are the maxima

* the internal birdies heard on 666 and 729 disappear with the radio connected to An200

Signals above 1400 tend to have lower sensitivity. Unsure if this was effected from

the high levels of the loop

** 15 is the minimum signal strength