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XHData D-808

Posted: 17 Feb 2018 10:47
by satnipper
Not been much talk of this one here. All bands including RDS Chinese portable. Google for reviews and prices - £81 ish.

Stuart

Re: XHData D-808

Posted: 18 Feb 2018 08:19
by Patrick73
Hi there !

I ordered mine on Monday, received yesterday (€66 / £58, including shipping).
More to follow ;-)

Re: XHData D-808

Posted: 19 Feb 2018 19:39
by satnipper
Received mine yesterday. Seems a keeper - good MF sensitivity. RDS seems ok as well but need some lift conditions to see just how good it is.

Tecsun 310 and 380 for sale - £10 each!

Re: XHData D-808

Posted: 20 Feb 2018 19:39
by Patrick73
It is slightly less sensitive compared with the PL-380 (at least the one I own).
Slightly less selective as well. Sounds like the DSP is more "agressive". When tuned to a weak station close to a louder one, one has to fine tune / detune by 10 20 or 30k for the signal to become audible and to lock on. No such behaviour on my Tecsun.

Good points : RDS is fine, audio not bad.
Very sensitive on MW (but still showing the so-called "soft mute" issue when tuning. Can be a bit annoying).

For less than 70 euros a nice radio, probably one the best in its range.

Re: XHData D-808

Posted: 23 Feb 2018 22:17
by simbeav
Mine arrived the other day as well. The PL-606 had developed a fault on the volume dial.
WFME yesterday morning and VOCM this evening coming in OK with just the internal antenna.
RDS seems ok - No DX at the moment, but both Bridge FM and GTFM which lesser radios struggle with RDS at my QTH were resolved easily and quickly.
OIRT a nice bonus. Direct frequency tuning makes a big difference to the 606.
Haven't tested HF too much as the noise here is too great to get much with a whip.
All-in-all very happy.

Re: XHData D-808

Posted: 23 Mar 2018 11:41
by KPC850
MW band modes from the manual online:
Activate 9/10kHz Tuning Button
·When in 9k mode, the frequency range is 522-1620kHz, intelligent step is 1kHz / 9kHz (for Asia, Africa and Europe)
When in 10k mode, the frequency range is 520-1710kHz, intelligent step is 1kHz / 10kHz (for North America)
They seem to have forgotten/overlooked the Australian market (or visitors bringing the radio there), Australia has 9kHz MW steps but have an expanded MW band up to 1701kHz (this receiver only goes up to 1620kHz in that mode according to manual).

Frequencies 1621 to 1710 kHz are completely inaccessible in 9kHz MW step mode - as well as normal tuning, keying in the frequency digits will not work either , nor will fine tuning in 1kHz steps go above 1620 (and it isn't the case this range get moved into SW coverage).
Even is you save a preset from this frequency range whilst in 10kHz step mode , then try go back to 9kHz step mode, the preset gets erased!

Re: XHData D-808

Posted: 26 Mar 2018 15:44
by KPC850
Some very clear pics of the inside of the XHDATA D808 in a posting on this thread on a Russian messageboard:

http://www.radioscanner.ru/forum/topic4 ... msg1353258

I spot a Crystal of 35.328MHz - This is related to Airband mode - this crystal is only active on airband receive. Another radio along side it picks up a XTAL harmonic on 106.0 MHz FM approx ( 35.328 X 3 = 105.984 ), when the XHDATA is in AIRband mode.

Also two other crystals at least one (though I assume both) are 32.768 kHz a common clock frequency (one 32.768 for microprocessor, the other for DSP chip). On some other DSP receivers, harmonics of 32.768kHz may cause noticeable hetrodynes on some AM frequencies (depending on signal strength etc) , 882kHz for example would be one (a harmonic of 32.768 kHz is 884.736 kHz so a 2.736 kHz whistle may be there on 882kHz) (edit - the XHDATA seems to be free of this effect)

(Some edits to my above post made as I have since obtained one!)

Re: XHData D-808

Posted: 07 Nov 2018 22:33
by KPC850
I don't wish to take from the undoubted positives of the radio, but one issue with the XHDATA D808 I have used - there is a surprisingly long pause of complete silence of just over 4 seconds when switching to MW or LW , or even switching between MW and LW.
Switching to its other bands this mute pause isn't as bad, slightly under 3 seconds, but still longer than might be expected.
I assume all are the same?

Is the above technically necessary? I doubt it.

Before you get used to it, switching to say MW you may momentarily wonder have you accidentally done something to switch the radio OFF before the just over 4 seconds of muting/silence is up! (especially if you have difficulty seeing the display due to no glasses, or visual disability) or else you instinctively go and turn the volume up before audio actually returns!

During some recent FM tropo, and some FM DXing whilst out and about with this radio, I would sometimes want to briefly switch to MW (AM) to confirm the identity of some weak distant (BBC) FM stations that also broadcast on AM, and I was again irked by the pauses in switching bands.
On the other hand, switching presets within the current waveband is responsive without delay.

Re: XHData D-808

Posted: 10 Jan 2019 10:38
by tyrell
Quick review ...
I got this radio this week, and managed to use it every day so that I can bring a first return of experience.

First, I had read it was deaf on LW.
I can attest that it could clearly receive RTL, Europe1 and BBC (although signal is weak ... I'm living in Belgium)
Maybe it was not as good as, for example, the DEGEN 1103, but it was perfectly fine for me.

Then, about the following points:

- Sound quality: i'd say it was ok, better than the PL-380 (which kinda sucks), worst than the Degen 1103. Volume is enough, bass is not present, but I can live with it.
- Ease of use: not so good, as some stuff is rather awkward, like the presets memory pages. Also, switching from AM to SSB is SLOW. Takes several seconds. On this point alone, I think they could re-engineer the whole stuff and a lot of things could be enhanced.
- Sensitivity: This was good, but maybe not as good as the Tecsun PL-380 or Degen 1103.
- Selectivity: Yes ! With a lot of IF Filters, this thing is brilliant.
- Bands coverage: definitely very nice. The addition of AIR band is a nice bonus. And we can use an externa antenna. Nice ! Also, FM is stereo using the headphones jack.
- Extra features: no mp3 player, or BT capability. But again, I'd prefer to use a dedicated device with a lot of "oomph" for that.

All in all, i'm happy with it but I think there's quite a lot room for enhancement, on usability side, first.
This is perfect pocket radio I'd probably bring with me at my next holiday destination.
But other radios are much easier to use.
We must however take the price into account, and this radio is really cheap (I paid about 65€) and offers a lot for your money.

Final score: 8/10.

I hope this helped :)

Tyrell

Re: XHData D-808

Posted: 12 Mar 2019 21:08
by KPC850
A few points about the XHData D-808 AIR band:

A positive: No muting effects whilst manually tuning along AIR band (In contrast to the 'mute-then-fade-up' effect with manual tuning on its LW/MW/SW ! )

Unlike the FM band, the Airband uses a 'traditional' 10.7MHz IF with the local oscillator 10.7 MHz above. (this might be useful to know for some as the local oscillator radiation in the vicinity could be used for checking other receivers)


Images in AIR-band:
I notice images of strong signals approx 21.4MHz higher can occur, for example strong amateur 2 metre nFM signals 145-146 MHz might appear 123.6 to 124.6 (tune along in the smaller 1kHz steps due to slope detection as its AM reception! , and use widest AM bandwidth)

Also strong low-UHF signals 10.7MHz either side of harmonics of the Local Oscillator may also be heard.
The strong TETRA base station buzzing can appear on sections of airband for this reason, eg the 390-395 MHz TETRA bases may have images between 122.86 to 124.53 MHz if you do the math.

likewise PMR 446 MHz walkie talkies with channel 1 to 8 could appear as images from 134.402 (PMR Ch 1) to 134.431 (PMR Ch 8 ) , again fine tuning in 1kHz steps due to slope detection

Doing another calculation the Ham 70cms band 430.0 – 440.0 may have images from 129.06 - 132.4 with very strong signals.


If images of strong signals from higher bands are a problem to desired Airband reception, detuning a couple of kHz either up or down may help (using widest 6kHz bandwidth setting).
You could of course try an external airband aerial and suitable low pass or bandpass filter to tackle images if required for serious airband listening..