开云体育

Sorry I haven't followed up on some of your questions pertaining to my 817
which I received from Japan . I left off where I had reset a couple of the
hf parameters in order to measure maximum power capability .

I then ,at that point decided to leave the rig at 6 watts output . Since
that time I received low audio reports (too much dynamic range ) , I
immediately suspected that by changing the power settings that the alc was
affected . I then attempted to increased the ssb tx audio in the user menu
settings , its default value was 50 , at 64 I became aware of a problem ,
the rig had no tx audio at 64(maximum value for this setting is 100 ) .
Since the electronic level control that is used to attenuate mike level is a
serial input device I assumed that Yaesu had a software bug , however since
there was a lack of mike gain available to develop sufficient alc at 6 watts
to make the audio punchy (remember : this radio relys heavily on alc for a
full envelope as there is no DSP or pre-processing, it has no other form of
processing but alc) I then , having taken note of the original values in the
alignment menu , reset the 817 to the factory values . I continued to
receive "thin" audio reports (too much dynamic range ) .

The audio could not be turned up high enough due to this "software bug" and
the only way that I could develop the alc level required for communications
audio was to "mouth " the mike and speak a little louder than normal (this
becomes a problem with 3 kids sleeping ) . I contacted Mike at Yaesu and
informed him about the bug and that the radio could never reach full tx mike
gain . A few days later he received positive confirmation from Japan that
there is an audio bug and Yaesu feels that it will not hinder the
performance of the radio and that they will market in North America with
this bug.

I disagree with their statement completely as I have hands on experience
with the rig and it does not modulate sufficiently nor develop adaquate alc
unless I speak close and loud .

The characteristic of the bug is as follows ,when one turns up the mike gain
(ssb mike gain) past 64 the gain begins again from 0 (zero) and increments
up 36 counts to digit 100 , if you compare the gain setting (with a scope)
of 100 to a setting of 36 you will see that both levels are the same . I
proposed an intermediate fix so that I wouldn't have to disturb my family
and that is to change some resistor values on the 1st speech amp to increase
the gain by approximately 6 db . I don't believe that Yaesu will impliment
this change and the radio will be released with this bug as they have
stated.

Aside from this I still love the radio and hope that Yaesu fixes their
firmware quickly so that I can purchase a second one . I am currently
working in Washington DC for the week and have worked DX ( Moscow) and some
local US stations on 20 meters simply with a long wire dangling out the
window of the hotel from the 8th floor . I really love the radio , just wish
Yaesu would correct the problem before releasing the first version , Without
opening the rig I will endevour to find a suitable replacement mike .

Just one last comment the mike gain works properly on FM and AM only ssb
mike gain is affected by this bug .

73's Howard VE2AED

LAte breaking news , I arrived back in Montreal last evening from DC and
connected my 817 to my 12 volt supply , went on 20 and suddenly had plumes
of smoke from my 817 and then the radio was of course dead . Something in
the rig had shorted out the batteries and caused a meltdown of the battery
holder , fortunately the springs on the battery holder became annealed and
opened up the battery circuit , had that not happened I would have probably
had a fire in the radio as I am using 1.6 amp AA nicads . I immediately
opened up the radio , removed the battery holder and measured 0 ohms from +
to ground , same on the external DC input . I decided I ad had enough for
one day since I had been out of town all week and brought the schematic to
kids swimming lessons this morning . After tracing all paths only thing I
could come up with was that the torroidal rf power line choke had probably
shorted . When I returned home I immediately removed completely the main PCB
, removed the choke and voila it was in fact shorted . I then stripped the
torroid core of its 6 turns of no. 24 wire and rewound it with a higher temp
enamal insulation then the original one , I think Yaesu overlooked this part
of the circuit as after careful checking I observed that the melting temp of
the original enamal on this choke (T35) had a very low melting temperature
and to top it off there is no fuse what so ever between the internal
batteries and the radio or for that matter the external connector and the
radio , If this choke fails you have a disaster . I have taken a photo of
the old wire and the newly installed choke and will post it tomorrow if I
can find some time . I must say that removing the main PCB was very simple
and I was impressed with the layout and the aluminum frame construction
which is the TX heatsink as well , the rig is extremely easy to service in
my opinion . I still like it very much and in no way am I trying to
influence anyone here as to what choice to make , I am being purely
objective and factual . The receiver sounds great and for those of you that
asked there is no DSP in this radio , If in fact there were I wouldn't be so
demanding about the mike gain bug which you will all probably see on the
first run .

I did try an electret mike with higher output and it compensated for the
lack of gain , problem was that it was originally meant for a vhf HT and had
a poor shield which would cause rf feedback when I used an antenna close to
the rig .

Hope this letter has been of interest to all of you .

73's
Howard VE2AED

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