DMR: Modelli di radio da *NON* utilizzare

Salve, vi allego copia dell'email inviata dai gestori di alcuni sistemi americani che raccomandano di non utilizzare alcuni modelli di radio.

Nello specifico si parla di:

Baofeng DM-5R, Tytera MD-398, Radioddity e tutti i relativi cloni.

In soldoni, come meglio spiegato nella mail, queste radio trasmettono con un timing sbagliato e, trasmttendo sullo Slot 1, vanno a disturbare lo Slot 2. I possesori non se ne accorgono ma causano pesanti interferenze sui sistemi impegnati. Non hanno problemi se utilizzate in diretta o in FM analogica.

Per le radio tipo Tytera MD-380 e MD-390 (e cloni vari) si raccomanda l'upgrade all'ultimo firmware disponibile.

Segue il comunicato originale:

Sent: Friday, November 25, 2016 7:06:25 AM
Subject: [Rmham-members] Problems with New Baofeng D, TYT MD-398 and
Radioddity Models

During 2016 we have noted some new and good DMR radios, and unfortunately we
have also seen some radios which cause concern. The radios in question are
the Baofeng DM-5R, TYT MD-398 and the Radioddity GD-55.

At this time Rocky Mountain Ham Radio is requesting that amateur operators
refrain from using the Baofeng DM-5R, TYT MD-398, the Radioddity GD-55
radios on the RMHAM or DMR-MARC Repeater Systems. This request also includes
clones of the above radios such as Pofung, Retevis, Chierda, VITAI, Juentai,
SAMCOM, Zastone, HYDX, etc.

Early tests show serious problems with these radios which will jam other
users and severely degrade the repeater system. Further tests are planned
and we will keep our members and users informed of the results on the
www.rmham.org web site. This request does NOT pertain to the TYT MD-380 and
MD-390 and the use of these radios remains acceptable. We do strongly
recommend updating to the most recent firmware for these units. In addition
you can find a list of radios known to properly interoperate with our
system, as well as sample code plug to program your radios, on the
www.rmham.org website.

In a nutshell here is what is being observed with these radios. When these
radios transmit on Time Slot 1, Rocky Mountain Wide on most of the RMHam
repeaters, they will actually transmit for a significant amount of time
within Time Slot 2, which on the RMHam system are usually North, South or
Denver. The net result? These radios in effect are jamming or causing
harmful interference to the user in Time Slot 2. The user of the Baofeng
DM-5R, TYT MD-398, Radioddity GD-55 radios or their clones will be able to
use Time Slot 1 and will have no idea they are producing harmful
interference to other users.

If you already own one of these radios all is not lost. You do have some
options. These radios appear to function normally in FM Analog and DMR
Simplex modes. If you purchased your radio from Radioddity or their Amazon
affiliate they are honoring the 30-day 100% satisfaction guarantee. The
manufacturers and importers are not currently considering this a product
flaw. The radios and upgraded firmware are advertised as Time Slot 1 only.
They are not currently addressing the jamming issue. For the details
concerning the protocols and more technical details See
www.rmham.org/wordpress/dmr-tier-i-radios-technical-side/