Sunday, January 31, 2021

Tecsun PL600vs550 comparre test

 as noticed the radio has already been given )

Here is a special article on how PL600 differs from  550 !

Last week  i took  the 550  from my relatives house for a short timed exhaustive check on  the similarities and the differences between them. Believe me  this radio  has many major and minor upgrades to 550  that seems  a rather different product! Also notice that my PL are   come from the earlierst bunches they made (ard 95 ?)

Look  at  both here! They seem as the same !

 


 

Just start from  the external design for the  differences  :

POWER LOCK TIMER  is for the 550 


POWER  TIME-SET TIMER 1 TIMER 2  for the 600


By this   way the lock button gets rid from here  (correct ! )and appears in another position ,later  shown. They put the  time set for  easier  time processing


Now on the display:

Here is the 550's LCd display:



And here is the 600's display


Nearly not so significant . ut there are  2 minor changes: The battery indicator on 550 is shown as graph  in the S meter while the indicator on the 600 is shown inside  the battery 

Now on the board :


550
:


600


and now on the remain 550 :
the image is turned by 90 degress:
knobs: tuning knob , antenna  tuner , volume
light snooze /tuning mode  ------- page /scan mode/if shift /bw&stereo 



and for the 600
tuning knob , BFO/ volume
light/snooze - tune fast slow & lock ------ preset- page- ssb- fm stereo& BW 



And now more on the  operation: 

600 memories instead of 550 !

1. ON the 600 you may add two more bands (mostly useless ! ) LW and AIR .
I have  tried several times  to listen to the AIR band after using my Yupi  scanner but still using strong signals  on the YUpi , nothing could be found on same freqs on 600 except  sometimes harmonics from shortwave stations. On LW  the signals  were very very poor !

2. Antenna switch : the switch  is rather and attenuator with more than 20 db in the normal  mode quite higher than the 550 . Tha means  all signals it can be used only in very strong signals. I just have to keep it on the DX mode

3. The MW  band sensitivity  that seems  quite poor on the 550 , is quite better on 600  though this is under discussion

4. The radio bands are here: full 150- 30000 mHz  in LW (150-500) MW (500-2000) SW(2000-30000)  78-108  for FM (adjustable  to 88-108) VHF  118-138 MHz with  AIR and LW firmware activated and vv.

5. The BFO here replaces  the 550's antenna tuner and operates together with the SSB button with a ca 3 kHz range. Did not test in full

6. The tuning knob has a very nice feeling Its tuning does not  have any gaps as in the 550 and is very smooth. Using the tuning button you select between fine tuning (1 kHz AM , 10 kHz FM) fast tuning (MW 9 or 10 / SW  5 / FM 100 kHz /VHF 50 kHz  ) and auto tuning (fast or slow depending on the speed )

7. Audio levels nearly same from ears and speaker . ON 550 audio was stronger on earphones

8. Audio Fidelity : 550  has better  fidelity in all cases :  Using speakers the 600  comes bassier in all cases . FM is very clear from speakers  for both  though 600 gives still  bassier audio. Using  earphones on FM, the quality  goes over 550  with more trebles.

9. AM filter bandwidths : 550  has broader bandwidths. A very strong station can be  listened 40 kHz far. narrower bandwidth increases  sensitivity . IN contrast the 600 has narrower  bandwidth and slightly decreases sensitivity.

10. Fm band images : 600 has lower image levels than  the 550 and  come from stringer signals only  . For example 79.2 mHz  comes from 100.6 . the 550 had stringer image or this station .

11. SW band images  : Images  on 600 are nearly nonexistent . A image signal of 550 on 4995  dd nt exist on 600 

12. Found that the correct freq for 600 is tuning off by -1 kHz ! 

13. The 550 had no good AGC . Strong stations  are heard  quite louder than the poorer. 

14.  550 upon start , while using ears  does a strong sound that might destroy the  ears. 600  solved this problem


About  radios sensitivity!

this is  still under discussion  as it was for easier to test 600 with 1102  than 550 !!! Using my diversity 'theorem' again here:

Two radios are used close to other. Their telescopic antennas are unfolded in  the same length / surface. Ear buds are connected into respective audio outs of radios one earbud is used for a head diversity  audio. First  audio  is determined by  a  strong and clear  station so that  both single ear buds generate a mono sounded audio in your head (i.e. at the center ).This is  what we can scale 5 at a scale of 1-9. For a very poor signal if an audio is stronger in the left  side will will rated from 1-4  and on the right side at 6-9 with 1 and 9 being the only sounded points. UNder this  theorem which audio is stronger , can mean  a higher sensitivity  towards  the corresponding radio.

Using this  theorem 600-550 were determined as 1-9 in this scale . I used the  Sandisk Fuze and the Koss 315  ears

MW band: this was  the most difficult as here this theory is invalid and required further scrutiny with diferrent reference audio stations (I used 1044 kHz a local station from ERA ) . BY a way both radios seemed to have the same sensitivity (though 600 signal indicator shown higher signals!) though as per the list below most signaling goes to 600 (with one reason 600  being bassier ):

530     2
576     3
648     4
801     4
900     2
1008   2
1133   6
1240   4

but extending it could lead to errors

SW band: here the problem  is less  difficult than the MW . I Used the 9420 kHz  as reference freq  to manage the diversity numbers . Using on start 1044 it lead me to some level of errors . A second point is that in all cases  i fine tuned  the ATU that lead  to some higher noise levels while looking at  nearly  marginal signals

3965    6
3985    5-7
4930    7
4940    5
5950    5
5975    7
6025    6
6030    8
6310    9
6976    8
7320    6
7480    4-6
9526    7
9895    8
11535    5
12095    5
13660    5
15110    5
15330    3
15745    6-7
17550    7
17560    9

Again here there was the problem of the bassy 600 that made the feeling of some shift  leftwards. As in result  from the above , 550 seems  having slightly (?) higher sensitivity  levels to 600 and in some cases  (bold numbers ) outperforms it.

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