Today's Message Index:
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1. 04:24 PM - Comm Radio Transmit Problem (Robin Hou)
2. 04:50 PM - Re: Comm Radio Transmit Problem (Francis Herr)
3. 05:44 PM - Re: Comm Radio Transmit Problem (Kelly McMullen)
Message 1
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| Subject: | Comm Radio Transmit Problem |
The Terra 760D comm radio in my Pazmany is getting harder for ATC to hear o
ver time. Last weekend, my home field tower controller couldn't even hear m
e when I was only 5 miles away.-=0A=0ASo I formed a plan to find the issu
e relating to my comm radio or the antenna. My plan was to remove antenna c
oax cable from Terra comm and connect it to my Icom portable radio then go
flying. If tower controller could hear me over the Icom without issue, the
problem most likely is in the Terra comm.=0A=0AFeeling good about my plan,
I went ahead and made the needed connections, including connecting Icom to
ship power. I also connected my headset directly to my Icom bypassing inter
com. I tested it with ground and got a "loud and clear" reply.-=0A=0AI th
en started the engine, listened to ATIS, then called ground to taxi. This t
ime the ground controller said he only received a transmit carrier. Thinkin
g it maybe noise from ship power, I connected Icom to its battery pack then
call ground, but the ground controller still could not hear me. I then tur
ned the master switch off, called ground again and received a "loud and cle
ar" reply. All of the above were done while the engine was still running.
=0A=0AI think the problem maybe in my charging system, most likely my alter
nator. But I have no idea what to do next to locate the problem. Any sugges
tion?=0A=0AThanks in advance,=0A=0ARobin Hou
Message 2
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| Subject: | Re: Comm Radio Transmit Problem |
Hi Robin,
Not sure about your specific system; but, how old is your main battery?
My radios had some issues until I replaced the four year old (Concorde)
battery. Maybe the alternator could not keep the battery supplied with
enough volts and enough amps to run the on board system?
Suggestion: swap in a new battery and see if it works.
Francis
On Jun 4, 2014, at 7:23 PM, Robin Hou wrote:
The Terra 760D comm radio in my Pazmany is getting harder for ATC to
hear over time. Last weekend, my home field tower controller couldn't
even hear me when I was only 5 miles away.
So I formed a plan to find the issue relating to my comm radio or the
antenna. My plan was to remove antenna coax cable from Terra comm and
connect it to my Icom portable radio then go flying. If tower controller
could hear me over the Icom without issue, the problem most likely is in
the Terra comm.
Feeling good about my plan, I went ahead and made the needed
connections, including connecting Icom to ship power. I also connected
my headset directly to my Icom bypassing intercom. I tested it with
ground and got a "loud and clear" reply.
I then started the engine, listened to ATIS, then called ground to taxi.
This time the ground controller said he only received a transmit
carrier. Thinking it maybe noise from ship power, I connected Icom to
its battery pack then call ground, but the ground controller still could
not hear me. I then turned the master switch off, called ground again
and received a "loud and clear" reply. All of the above were done while
the engine was still running.
I think the problem maybe in my charging system, most likely my
alternator. But I have no idea what to do next to locate the problem.
Any suggestion?
Thanks in advance,
Robin Hou
Message 3
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| Subject: | Re: Comm Radio Transmit Problem |
The other side of the coin could be either alternator diode failed or
the alternator noise filter (capacitor/condenser) failed.
On 6/4/2014 4:49 PM, Francis Herr wrote:
> Hi Robin,
>
> Not sure about your specific system; but, how old is your main battery?
>
> My radios had some issues until I replaced the four year old
> (Concorde) battery. Maybe the alternator could not keep the battery
> supplied with enough volts and enough amps to run _the on board _system?
>
> Suggestion: swap in a new battery and see if it works.
>
> Francis
>
> On Jun 4, 2014, at 7:23 PM, Robin Hou wrote:
>
> The Terra 760D comm radio in my Pazmany is getting harder for ATC to
> hear over time. Last weekend, my home field tower controller couldn't
> even hear me when I was only 5 miles away.
>
> So I formed a plan to find the issue relating to my comm radio or the
> antenna. My plan was to remove antenna coax cable from Terra comm and
> connect it to my Icom portable radio then go flying. If tower
> controller could hear me over the Icom without issue, the problem most
> likely is in the Terra comm.
>
> Feeling good about my plan, I went ahead and made the needed
> connections, including connecting Icom to ship power. I also connected
> my headset directly to my Icom bypassing intercom. I tested it with
> ground and got a "loud and clear" reply.
>
> I then started the engine, listened to ATIS, then called ground to
> taxi. This time the ground controller said he only received a transmit
> carrier. Thinking it maybe noise from ship power, I connected Icom to
> its battery pack then call ground, but the ground controller still
> could not hear me. I then turned the master switch off, called ground
> again and received a "loud and clear" reply. All of the above were
> done while the engine was still running.
>
> I think the problem maybe in my charging system, most likely my
> alternator. But I have no idea what to do next to locate the problem.
> Any suggestion?
>
> Thanks in advance,
>
> Robin Hou
> *
>
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