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Old 07-10-2018, 6:24 AM
marlbrook marlbrook is offline
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Join Date: Feb 2016
Location: Devon, UK
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Default Flawed engineer's report

Quote:
Originally Posted by TMac20 View Post
One of the replies I have on this is as follows;

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Here is the reply from our engineer:

The AR-DV10 brochure states +/-5ppm frequency stability. In clear that means that if you are receiving a signal at 450MHz, it might drift by +/- 2250Hz.
At 140MHz itís approx +/-1000Hz.

After turning on the AR-DV10, internal temperature is rapidly increasing , that would make the frequency drift.

+/-2250Hz is no problem for decoding of digital modes, since the filter bandwidth is 15000Hz.

In comparison, the AR-DV1 is 2.5ppm, AR5001D is 0.1ppm.
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1. DMR, along with P25 phase II and NXDN use 6.25 kHz IF Bandwidth, NOT 15 kHz as it states. That in itself is enough to explain why the DV10 is just NOT receiving/decoding many Digital signals other makes of Radio (and AOR's DV1) are managing to find.

In this respect it is VERY IMPORTANT for people to realise that because the DV10 has drifted that far off frequency, quite often it will just remain totally SILENT despite a Digital signal being present.

With an off-frequency Analogue signal you may hear it, but not as well if it was actually monitoring the correct Frequency (as one would expect from a high end Receiver i.e. the one the DV10 is showing on its display). With a Digital signal, unless it is very strong, there will be no indication that a transmission is in progress whatsoever.

2. Irrespective of what this Report implies, the DV10 as it warms up has been shown to drift so far that even HF signals need to be manually re-tuned to hear them correctly. As the desired Frequency increases, so does the drift figure. There are YouTube videos about this, and Owner reports on the Facebook Forum.

3. When it comes to the DV10 missing Digital signals, again people should look at the YouTube videos and read the posts at the Facebook Forum.

4. Reports like the above may try to 'blind people with science', but the bottom line is a DV10 user who was in a position to compare reception with another Digital radio cannot fail but to be bitterly disappointed with the actual results.

5. The ARDV1 is fine. No drift. No re-tuning necessary at any Frequency. Finds, receives and decodes Digital signals on the Frequency it is displaying. The DV10 is advertised as setting 'NEW STANDARDS'. Sadly it does, but new 'lower standards' which many are finding unacceptable.
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