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Promax TV Explorer

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The person I contacted was:

Jordi Castel, area manager Promax, email jcastell@promax.es

From my reading, doesn't have data logging, constellation display, minimum power range for COFDM measurements at 45dBuV is a bit high for my liking.

Apart from that, nice machine, since it is almost one size fits all, but as I already have another instrument or three, my interest academic only.

I also wonder what latency for the various functions is.

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The person I contacted was:

Jordi Castel, area manager Promax, email jcastell@promax.es

From my reading, doesn't have data logging, constellation display, minimum power range for COFDM measurements at 45dBuV is a bit high for my liking.

Apart from that, nice machine, since it is almost one size fits all, but as I already have another instrument or three,  my interest academic only.

I also wonder what latency for the various functions is.

I agree about cofdm measurements being a bit high

Perhaps the Unaohms with their higher sensitivity and low latency may still be in the race after all

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Welll, don't know if apples are apples here,

On page 7 of Unaohm T 40 manual, spec for 8Mhz bandwidth is -40dBuV LNB off to -45dBuV LNB on (I presume LNB is a typo, and I'm waiting for Laceys to get back to me on that one),

and Roversat PDA-7 implies minimum useful 30dBuV, but will go to 25dBuV.

Latency is worse on the PDA-7, but in my experience it out-performs the T-40 in the sensitivity stakes.

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Welll, don't know if apples are apples here,

On page 7 of Unaohm T 40 manual, spec for 8Mhz bandwidth is -40dBuV LNB off to -45dBuV LNB on (I presume LNB is a typo, and I'm waiting for Laceys to get back to me on that one),

and Roversat PDA-7 implies minimum useful 30dBuV, but will go to 25dBuV.

Latency is worse on the PDA-7, but in my experience it out-performs the T-40 in the sensitivity stakes.

Excuse the long text, I took th liberty of sending the following mail to Castell from promax and got his reply below:

Dear Mr. Castell,

I have just ordered a PRODIG-5 and looking at the specs of it, I found that the minimum channel power for decoding COFDM is 45 dBuV.

Is that the case? What would be the result if the meter is put to measure COFDM levels below that?

What is the latency of the COFDM measurements?

How is this meter as compared to the Unaohms and Rover's? I currently own a PROLINK-2 and a PROLINK4C Premium, how would it compare to both?

Cheers

Dear John,

Thanks a lot for purchasing a PG5.

Lots of questions. Some of them I may be able to answer exactly, but a comparative analysis between our meter and the competition is hard for me to do as, first of all, it is very difficult for me to be objective and second, although I know the different models of Unaohm and Rover, I am not an expert on them, what I can do is to explain what we do and then you compare it to the others:

- The minimum level at which the COFDM tuner will lock is not 45 dBuV, in fact, this is just a minimum value recommended for a digital reception. The meter will lock and display MER and BER values for power levels from 35 dBuV onwards although you must take into consideration that the MER's will also depend upon the type of modulation used (64 QAM, QPSK, etc). The MER has a top measured value of 32.9 dB's although this value you will hardly get in a real live installation.

- The latency (I assume you mean the time it takes for the meter to lock and display the info) is almost immediate. I cannot give you a figure because it has too many variables (quality, levels, SR's, echoes, etc), but all you can do is compare it to the PROLINK's that you have and you'll see that the response is much faster. For instance, the explorer function has the ability to find out all the parameters of the digital signal under test, if you go to a QPSK or COFDM signal and tell the meter that the signal under test is ANALOGUE (thus you are lying to the meter), and them press the EXPLORER KEY, it will not take more than 1.5 seconds to get back to you with a MER and BER value, it is then to be understood that the meter will be real fast to refresh the proper values once the right parameters have been found. Just try it when you have a chance.

- As for a comparison between our meter and the competitors, I can only say that, apart from the mechanical advantage, the pg5 has a real spectrum display with arrow keys to change SPAN's and REFERENCE LEVELS, you can never go wrong with the digital parameters, it has Lithium Ion batteries as standard, MPEG-2 and all three modulations on one instrument. Just look at what instrument from the competitors has that (and what price they quote). The PROLINK-4 Premium has to be seen as a more professional meter (constellations, loggers, measuring filters, DAB, etc) but the sure option for a day to day installer will definitely be the PRODIG-5.

Please let me know if you have any more questions, I'll be glad to help you out.

Best regards

At 18:10 13/10/05 +1000, you wrote:

Dear Mr. Castell,

I have just ordered a PRODIG-5 and looking at the specs of it, I found that the minimum channel power for decoding COFDM is 45 dBuV.

Is that the case? What would be the result if the meter is put to measure COFDM levels below that?

What is the latency of the COFDM measurements?

How is this meter as compared to the Unaohms and Rover's? I currently own a PROLINK-2 and a PROLINK4C Premium, how would it compare to both?

Cheers

Jordi Castell

Area Manager

PROMAX ELECTRONICA S.A.

Francesc Moragas 71

08907 HOSPITALET

SPAIN

TEL: 34 93 260 2002

FAX: 34 93 338 1126

http://www.promax.es

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minimum power range for COFDM measurements at 45dBuV is a bit high for my liking.

After making that gratuitous comment I checked the 3 instruments I have and the readings on all of them deteriorates once the level drops below 45dBuV.

Some of the installations I do are in areas where the incoming signal is <45dBuV, my solution is to add a preamplifier to the antenna being used for testing to get more of an idea of what the final result at the wallplate will be. This is much easier if the instrument in use has a power feed as it is not necessary to carry a battery on your person.

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Agree but if you can't get a stable reading becuase the meter keeps going below level where it will work then its frustrating and time consuming.

I also use an inline masthead amp powered off my T40 when doing tests in terminally weak areas as the extra gain brings the BER /MER reading up to a stable point.

With experience I know how far to the limit to push it for reliable recieption.

Just because the channel power is below 40dBuV doesn't mean don't waste your time installing digital.

As long as the MER comes up to at least 24 with an amp and the channel BER is not much less than 1E03 then you can be fairly confident of a happy customer :blink:

However at these borderline cases I inform customer of potential for failure.

Customers happy to have such wonderful pictures after many years of analog ghosty,bendy ,snowy,distorted crap

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Agree but if you can't get a stable reading becuase the meter keeps going below level where it will work then its frustrating and time consuming.

I also use an inline masthead amp powered off my T40 when  doing tests in terminally weak areas as the extra gain brings the BER /MER reading up to a stable point.

With experience I know how far to the limit to push it for reliable recieption.

Just because the channel power is below 40dBuV doesn't mean don't waste your time installing digital.

As long as the MER comes up to at least 24 with an amp and the channel BER is not much less than 1E03 then you can be fairly confident of a happy customer :blink:

However at these borderline cases I inform customer of potential for failure.

Customers happy to have such wonderful pictures after many years of analog ghosty,bendy ,snowy,distorted crap

Totally agree with Bellotv.

MER and BER are the important results, but all decoders (comercial decoders) have a threshold below which, they cannot give up a proper Transport Stream out to the MPEG-2 decoder and thus causes pixellation.

If you power up the signal well above this threshold, you then have some room for a good MER reading under worst enviromental conditions, so Channel Power does matter under marginal conditions.

As for Powering the MH Amplifiers, the PRODIG-5 also has the possibility to do so.

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does the new Promax show cofdm reflections?

If you refer to the Echoes detection (distance and time to the secondary transmitter) no, it is not in it.

I own a PROLINK-4C Premium and it is included there, but rarely use it.

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really surprised you guys keep talking about signal level when it is BER / MER that matters.

No need to be surprised. No signal, no BER/MER.

The point I'm making is to keep the signal level up to a region where the measuring instrument can give "regular repeatable results" not affected by limitations imposed by the device making the measurement.

I also apply caveats to installations when level at the antenna is below 40dBuV as there is insufficient fade margin, but like bellotv, when people get near perfect pictures after years of crud, they are usually prepared to put up with intermittent picture/sound breakup.

As an aside, it's interesting that some STB's claim to be able to work down to levels of -80dBm, (and they do). These are the self installs I get to fix because the sound & picture keep breaking up.

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If you refer to the Echoes detection (distance and time to the secondary transmitter) no, it is not in it.

called AER its an option Unaohm have introduced to their entry level T40PLUS, with guard band indicator.

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I wonder if these features are implemented at the design stage and then introduced later as an inducement to upgrade or change the instrument?

Go fish here:

http://www.unaohm.it/dettagli.php?id=34&p=1&l=Eng

and here:

http://www.unaohm.it/public/prodotti/T40%2...0Rev.%201.0.pdf

Be nice if it had a display like my el-cheapo PDA

I remember this as well:

Constellation is a great feature, I have a whisper that other handhelds will add it in the not too distant future.

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I have bought one.

I am relatively new to digital measurements and am keen to share experiences with other who have a promax TV explorer. I'm pretty happy with it, I think it was a good buy.

Paul

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