Zinwell ZAT-970A? - Page 40 - AVS Forum | Home Theater Discussions And Reviews
Baselworld is only a few weeks away. Getting the latest news is easy, Click Here for info on how to join the Watchuseek.com newsletter list. Follow our team for updates featuring event coverage, new product unveilings, watch industry news & more!



Forum Jump: 
 5Likes
Reply
 
Thread Tools
post #1171 of 1187 Old 10-04-2015, 12:49 PM
AVS Special Member
 
Floydage's Avatar
 
Join Date: May 2009
Location: Fort Worth, TX
Posts: 1,850
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 147 Post(s)
Liked: 64
Yeah they should all be designed to prioritize audio over video. I wonder if the ATSC protocol takes that into consideration?

Floydage is offline  
Sponsored Links
Advertisement
 
post #1172 of 1187 Old 10-05-2015, 11:42 AM
Member
 
jvvh5897's Avatar
 
Join Date: Oct 2011
Posts: 133
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 35 Post(s)
Liked: 25
So, far I've played with a high-end Digital Stream box and the low end DTX9950, Channel Master D2A, RCA DTA800B (older Broadcom and newer but still Broadcom chips) and the Zinwell Zat-970A w Broadcom chips--I did pick up a Magnavox TB110 box the other day and haven't done much with it yet (look like the same insides as you see in the TB100 pics) . All have their own way of freezing up. The CM box will 'freeze' if it gets a signal drop and not come back even if the signal does, but the box is not really locked up as all you have to do is change channels for a second and the box is up--it just does not seem to recover well from the signal drop (though sometimes you do need to power down the box to recover). The high-end DS box will just freeze up (not a LG processor in that box) as will the RCA's and require hard power reboot to get back going.
My guess would be that the Zinwell having audio running was just an odd chance and the more likely freeze will be like the RCA.
I haven't really gotten any box to duplicate what we see in the field. I have gotten an RCA to stop processing the channel if I corrupt the PID info--if I just corrupt the VPID the audio will keep running. And I have gotten an error state on the RCA that gets a bunch of register data dumped out the serial port that also seems to be a 'freeze' event, but I can't say for sure that that is the state we get in the very rapid up/down signal conditions that we get boxes to freeze on up at the shack. You have to figure that the PID corruption is moderately common under such conditions, but just about any part of the stream could be hit.


All the boxes have had about the same sensitivity and selectivity--some issue with the RCA boxes with adjacent channels that other boxes did not have (odd seeing that the Thomson tuner seems to be in most of the ones I've played with ), but all hold a signal to about 15 dB SNR before drop outs begin.

Last edited by jvvh5897; 10-05-2015 at 11:47 AM.
jvvh5897 is offline  
post #1173 of 1187 Old 10-07-2015, 11:57 AM
AVS Special Member
 
Floydage's Avatar
 
Join Date: May 2009
Location: Fort Worth, TX
Posts: 1,850
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 147 Post(s)
Liked: 64
I don't recall that happening with my two CMs but maybe the signal drop wasn't severe enough. Yet I infrequently get an interline twitter problem that I can only clear up via a hard reset removing line power while the box is on; when it comes back on it first displays the CM screen akin to a factory reset (but it's not factory reset).

Funny your timing of this post though. Last night my Hughes DirecTV HD receiver lost an ATSC channel when a National Guard transport 'copter went over my house, this on a major station that has just recently gotten weaker*. I had to toggle power to recover (but not what I call a hard reset). Note that this receiver is of an older generation chipset than CECBs and also doesn't have their level of sensitivity.

*I've been having problems for a few years now that appears to only affect some of my majors (FOX, NBC, CBS, and PBS (although PBS can be weak to begin with ($))), all UHF but not adjacent. ABC here is on upper VHF. Now granted the other stations are UHF but I admit I don't look at them as frequently, but I do check them when this problem crops up. Only one station at a time and sticks around for weeks. Appears to get worse during the evening (of course! Prime Time) but I don't monitor it all day and night. I suspect interference from say a ham radio operator although there's plenty of other possibilities these days (flaky > utility meter RF, home automation/portable/Wi-Fi RF, cell/microwave trunk, etc.). The funny thing is my solution: two-way combine a small loop antenna adjusted for the problem channel and located near ground level (near main TV/junction) with my attic antenna (big ol' VHF-UHF array). Unless it's proximity, I'm assuming my attic antenna has too much gain per the interference.

Floydage is offline  
post #1174 of 1187 Old 10-30-2015, 12:36 PM
Member
 
tripelo's Avatar
 
Join Date: Aug 2009
Location: Dallas, TX
Posts: 66
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 12
The ability of the ZAT-970 in a metal case to handle multipath was compared side-by-side to one of the more recent regular appearing ZAT-970s (with Microtune tuner).

Results:

Performance of the two (Audio/video dropouts or slight pixellation) was comparable. Performance was not identical, sometimes one unit would drop a syllable or slightly pixellate and then later the other unit would do similar.

Setup:

The main purpose was to evaluate performance in a multipath situation.

Receiving a difficult station over long distance (~100 miles). Measured signal level was more than sufficient for decoding.

Antenna feeding a low noise preamplifier fed to a high quality splitter. The two outputs of the splitter was connected to the two ZAT's which were connected to two TV's.

The use of a preamplifier effectively eliminated potential differences in converter noise figures.

After a period of time the splitter outputs were reversed and evaluation continued.
tripelo is offline  
post #1175 of 1187 Old 12-06-2015, 12:41 PM
AVS Special Member
 
seatacboy's Avatar
 
Join Date: Jan 2008
Posts: 1,133
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 43 Post(s)
Liked: 27
One feature of the ZAT-970A which is greatly appreciated is the Signal Quality meter. Most CECBs will display signal strength but not signal quality, which can be helpful in antenna positioning if you are trying to avoid intermittent loss of signal on a station which appears to be "strong".

What other CECBs offer a functional Signal Quality meter? At this point, we only are using a CECB on one television in our home and it's connected to this Zinwell model - though it's the plastic box version, not the early metal-box version.
seatacboy is offline  
post #1176 of 1187 Old 12-07-2015, 12:08 PM
AVS Special Member
 
Floydage's Avatar
 
Join Date: May 2009
Location: Fort Worth, TX
Posts: 1,850
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 147 Post(s)
Liked: 64
Quote:
Originally Posted by seatacboy View Post
One feature of the ZAT-970A which is greatly appreciated is the Signal Quality meter.
You're welcome!

It's possible some have intensity and quality combined by virtue of the chips they used, but I wouldn't bet it's too many of 'em.
________________
On the newer HD-capable boxes, I would suspect they use the latest generation chipsets as the old parts are most likely obsolete.

Floydage is offline  
post #1177 of 1187 Old 12-07-2015, 12:30 PM
Member
 
jvvh5897's Avatar
 
Join Date: Oct 2011
Posts: 133
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 35 Post(s)
Liked: 25
The Channel Master CM-7000 has something like the Zat box but it is very slow to update and is like it is averaging to get the reading.
I don't really like the quality meter, it sort of shows 100% even if you don't have a good signal or are about at the digital cliff.
I like a good signal meter that shows SNR or EBNO. You can get SNR from the Broadcom based boxes like the newer version of 970A or the newer of the two RCA DTA-800b. But you have to mod the code to get it.

The recording ATSC converter Sunkey SK-903H or its axess cousin has a good meter too. And HD out as I understand.

BTW, I've seen that video freeze but audio play happen in the Zin box a couple more times. The other day the signal loss message was popping up and down on the screen and video was going to black screen often, but the frozen video shot was all that showed up when the audio was OK. It stayed frozen that way for most of the day (I would have to walk in to the translator site so not a thing I wanted to do with the snow we have had. )

Last edited by jvvh5897; 12-07-2015 at 12:35 PM.
jvvh5897 is offline  
post #1178 of 1187 Old 12-07-2015, 02:45 PM
AVS Special Member
 
Floydage's Avatar
 
Join Date: May 2009
Location: Fort Worth, TX
Posts: 1,850
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 147 Post(s)
Liked: 64
I was thinking he was referring to the ZAT having two meters. But now I'm wondering if some of the single meter boxes display signal strength/intensity while others display signal quality?
I'll have to look at my CM tonight as I'm thinking its single meter displays "intensity." I looked in the manual but it's a POS.

Floydage is offline  
post #1179 of 1187 Old 12-08-2015, 08:22 AM
AVS Special Member
 
Floydage's Avatar
 
Join Date: May 2009
Location: Fort Worth, TX
Posts: 1,850
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 147 Post(s)
Liked: 64
Quote:
Originally Posted by Floydage View Post
I'll have to look at my CM tonight as I'm thinking its single meter displays "intensity." I looked in the manual but it's a POS.
After further review the CM manual does use the term "signal strength" (INFORMATION BANNER section on page 9). The actual OSD banner doesn't list anything; mine has an icon of a radiating antenna tower whereas the manual shows a little rabbit-eared TV displaying vertical signal bars (and my signal bar has % whereas the manual's is %-less, both are horizontal).

Floydage is offline  
post #1180 of 1187 Old 12-08-2015, 09:05 AM
Member
 
tripelo's Avatar
 
Join Date: Aug 2009
Location: Dallas, TX
Posts: 66
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 12
CM-7000 Signal Strength Indicator

Quote:
Originally Posted by Floydage View Post
After further review the CM manual does use the term "signal strength" ...
Floydage, this may be correct.

Back in 2009, a couple of units were measured:

Starting with just enough signal strength to indicate ~95%, signal indications were monitored as signal strength was reduced to near zero, then increased:

The measurement was repeated for number of channels across the UHF band.

Over the range, in a fairly linear manner, indications averaged about 10% change for 1.5 dB input change (See attached image).




.
Attached Thumbnails
Click image for larger version

Name:	CM7000 Signal Indication vs Attn.gif
Views:	96
Size:	10.4 KB
ID:	1106562  

Last edited by tripelo; 12-08-2015 at 09:27 AM. Reason: clarify
tripelo is offline  
post #1181 of 1187 Old 12-08-2015, 09:21 AM
AVS Special Member
 
Floydage's Avatar
 
Join Date: May 2009
Location: Fort Worth, TX
Posts: 1,850
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 147 Post(s)
Liked: 64
Quote:
Originally Posted by tripelo View Post
A couple of units were measured:
Good work and good ref. measurement info for this box down the road, thanks!
Yeah I figured based on the wording that it was more likely to be signal level than signal quality, but their manual is goofy.

Glad to be sharing that Cedar Hill antenna farm with ya.

Floydage is offline  
post #1182 of 1187 Old 12-08-2015, 09:29 AM
Member
 
tripelo's Avatar
 
Join Date: Aug 2009
Location: Dallas, TX
Posts: 66
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 12
Quote:
Originally Posted by Floydage View Post
...
Glad to be sharing that Cedar Hill antenna farm with ya.
Thanks, yes.

Made a couple of edits to previous post, maybe clarify.
tripelo is offline  
post #1183 of 1187 Old 12-08-2015, 09:57 AM
Member
 
jvvh5897's Avatar
 
Join Date: Oct 2011
Posts: 133
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 35 Post(s)
Liked: 25
In the code for the RCA DTA800b the values used for the signal strength start with SNR in dB then they do a little manipulation of them to get a scale from 0 to 100% from that. The tuner is read for something and a table that inverts the range is used with a little change that must take something like AGC and converts to SNR dB--so that should be pretty linear.

Oh, I forgot to mention that the quality in the Zinwell meter might be derived for something like BER. In the factory screen they show you how many bytes have had to be corrected--with good signal it is about 10 or less and as the signal gets bad it goes up to 10s of thousands before you get obvious dropouts. If you assume something like 15 Million bps for a channel then the 10 or so corrections are down around 10 to the -7 maybe -6 bit-error-rate and the 10s of thousands is getting up around 10 to the -3 and that is where you start to see the Q below 100%. At least that is what the Broadcom processor based Zat did for me.
jvvh5897 is offline  
post #1184 of 1187 Old 12-12-2015, 06:18 PM
Member
 
tripelo's Avatar
 
Join Date: Aug 2009
Location: Dallas, TX
Posts: 66
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 12
ZAT970 in metal case = ZAT857?

Came across an image of a ZAT-857 (attached below):





Externally, looks like the image of ZAT-970 in a metal case posted previously.

Located the manual for a ZAT-857.

http://www.ezdigitaltv.com/support-f...ser_manual.pdf

Software setup looks somewhat like software setup for the ZAT-970 in the metal case.
Attached Thumbnails
Click image for larger version

Name:	ZAT-857.jpg
Views:	72
Size:	24.9 KB
ID:	1116602  

Last edited by tripelo; 12-12-2015 at 06:20 PM. Reason: typo
tripelo is offline  
post #1185 of 1187 Old 12-13-2015, 08:54 AM
AVS Special Member
 
Floydage's Avatar
 
Join Date: May 2009
Location: Fort Worth, TX
Posts: 1,850
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 147 Post(s)
Liked: 64
Quote:
Originally Posted by tripelo View Post
Came across an image of a ZAT-857
A classic! Looks classier than the later versions, plus it has an actual display (pretty rare with CECBs). Note the Dolby Digital - common among Zinwells but not so much other CECBs. Metal case and built-in power supply - Channel Master would have been proud.

Per this I think internally it's more like a 950A which it appears to have preceded before the 950:

http://web.archive.org/web/201102260..._of_CECB_units

But that's interesting that it used that same very much more recent 970A case/style. Didn't the metal case 970A lack the extra features like record timer, favorites, etc? It appears per that 857 manual that this one lacks them too. Hmmm, maybe they were clearing out old parts...

Floydage is offline  
post #1186 of 1187 Old 12-13-2015, 11:09 AM
Member
 
tripelo's Avatar
 
Join Date: Aug 2009
Location: Dallas, TX
Posts: 66
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 12
Quote:
Originally Posted by Floydage View Post
A classic!...
Yes

Quote:
Per this I think internally it's more like a 950A which it appears to have preceded before the 950:

http://web.archive.org/web/201102260..._of_CECB_units
The above web page shows the 950A as having a Microtune tuner. This specific 970A doesn't have the Microtune tuner.

It has a tuner made of somewhat discrete parts:

The tuner was labeled DARQ59-6R-E:

Inside the shield was:

S3W - 3 lead Transistor, maybe BFG31R

R25- 3 lead Transistor, low noise VHF/UHF

R25-3 lead Transistor, low noise VHF/UHF

TDA6509ATT, Phillips PLL, 3-band Mixer Oscillator

CS5797 32 lead

A77000 2QN2 16 lead

Quote:
... Didn't the metal case 970A lack the extra features like record timer, favorites, etc?
Probably lacks those features, don't know for sure because:

Took the metal case 970A to KY for a multipath test, and left it there.

Quote:
...Hmmm, maybe they were clearing out old parts...
Seems like a reasonable explanation.

.

Last edited by tripelo; 12-13-2015 at 11:12 AM. Reason: typo
tripelo is offline  
post #1187 of 1187 Old 12-13-2015, 11:26 AM
AVS Special Member
 
Floydage's Avatar
 
Join Date: May 2009
Location: Fort Worth, TX
Posts: 1,850
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 147 Post(s)
Liked: 64
Quote:
Originally Posted by tripelo View Post
The above web page shows the 950A as having a Microtune tuner. This specific 970A doesn't have the Microtune tuner.
Yep that was my point, same as the 857 (i.e. I wasn't comparing to a 970A).
_____________
Wow a discrete tuner, well maybe they were using up old parts.
Ah I miss the good ol' days when us PCB-level RFEEs actually designed circuits rather than planting an IC on a PCB...

Floydage is offline  
Sponsored Links
Advertisement
 
Reply Coupon Eligible Converter Box (CECB)



Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off