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Old January 30th 05, 04:18 PM
Charlie
 
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Default Key line question

Using an ICOM 746 Pro with an AL-80B amp. According to their respective
manuals the AL-80B sources +12vdc at 100mA and the 746Pro can sink a max of
+16vdc at 500mA.

QUESTION:
Do I need an amplifier keying buffer according to the above specs? My
research shows primarily these devices are for new rigs keying older amps.
The Icom site recommends an interface for "all non-Icom amplifiers" but in
the case of the above specs it appears to me there is already a 4 volt and a
400mA "buffer" of sorts. The demands of the 80B are well inside the
capabilities of the 746 Pro. Right?

I'm not trying to save $50 or so but if the specs are right I don't need it.
My rig is new and I have about 300 qsos so far which amount to at least
1000+ successful amp keying events.

--

Charlie
Ham Radio - AD5TH
www.ad5th.com
Live Blues Music
www.492acousticblues.com





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Old February 2nd 05, 05:41 PM
Jim Phelps
 
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Default


"Charlie" wrote in message
...
Using an ICOM 746 Pro with an AL-80B amp. According to their respective
manuals the AL-80B sources +12vdc at 100mA and the 746Pro can sink a max
of
+16vdc at 500mA.

QUESTION:
Do I need an amplifier keying buffer according to the above specs? My
research shows primarily these devices are for new rigs keying older amps.
The Icom site recommends an interface for "all non-Icom amplifiers" but in
the case of the above specs it appears to me there is already a 4 volt and
a
400mA "buffer" of sorts. The demands of the 80B are well inside the
capabilities of the 746 Pro. Right?

I'm not trying to save $50 or so but if the specs are right I don't need
it.
My rig is new and I have about 300 qsos so far which amount to at least
1000+ successful amp keying events.

--

Charlie
Ham Radio - AD5TH
www.ad5th.com
Live Blues Music
www.492acousticblues.com



You're an Extra and need to ask this? Come on, I've only (previously) held
a Tech Plus and know that 12V is less than 16V and 100ma is less than 500ma!
Man, when I go to take my elements I just may go straight to element 4 -
just for fun!


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Old February 2nd 05, 06:35 PM
Charlie
 
Posts: n/a
Default

Hi Jim and thanks for the reply. It is more than just a numbers thing. The
ICOM website says to use a buffer if you are using a "non-Icom linear". They
don't bother to specify which non-Icom amps need a buffer . Obviously the
specs for each certain ly indicate no need. I have had some hams email me
saying to use a buffer "just in case". I suppose it couldn't hurt.

Good luck on the license upgrades... 73 / DX

--

Charlie
Ham Radio - AD5TH
www.ad5th.com
Live Blues Music
www.492acousticblues.com




"Jim Phelps" wrote in message
...

"Charlie" wrote in message
...
Using an ICOM 746 Pro with an AL-80B amp. According to their respective
manuals the AL-80B sources +12vdc at 100mA and the 746Pro can sink a max
of
+16vdc at 500mA.

QUESTION:
Do I need an amplifier keying buffer according to the above specs? My
research shows primarily these devices are for new rigs keying older
amps.
The Icom site recommends an interface for "all non-Icom amplifiers" but
in
the case of the above specs it appears to me there is already a 4 volt
and a
400mA "buffer" of sorts. The demands of the 80B are well inside the
capabilities of the 746 Pro. Right?

I'm not trying to save $50 or so but if the specs are right I don't need
it.
My rig is new and I have about 300 qsos so far which amount to at least
1000+ successful amp keying events.

--

Charlie
Ham Radio - AD5TH
www.ad5th.com
Live Blues Music
www.492acousticblues.com



You're an Extra and need to ask this? Come on, I've only (previously)
held a Tech Plus and know that 12V is less than 16V and 100ma is less than
500ma! Man, when I go to take my elements I just may go straight to
element 4 - just for fun!



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Old February 2nd 05, 07:24 PM
Jim Phelps
 
Posts: n/a
Default


"Charlie" wrote in message
...
Hi Jim and thanks for the reply. It is more than just a numbers thing. The
ICOM website says to use a buffer if you are using a "non-Icom linear".
They don't bother to specify which non-Icom amps need a buffer . Obviously
the specs for each certain ly indicate no need. I have had some hams email
me saying to use a buffer "just in case". I suppose it couldn't hurt.

Good luck on the license upgrades... 73 / DX



It shouldn't take more than a couple of dollars in parts to build you own if
you feel it's necessary. All you really need is a 12 volt relay. In the
Icom 756 Pro III manual it says to use a larger relay if these parameters
are exceeded (pg. 17).

I (in a former job), was a MARS director for one of the largest USAF bases
in the US (employment wise it was the largest and the sixth largest employer
in the state, Damn, I miss DARA and the Xenia groups). We used commercial
solid state rigs (in our case TS-440's) to excite Rockwell linears. We
didn't have any troubles operating at much higher (and closer to the max)
voltages and sink currents. I also miss the HyGain Discoverer73 we put up.
3 elements on 40 meters (well, just outside the band) and 1.5 kw PEP. We
were heard where ever we wanted to be.


  #5   Report Post  
Old February 13th 05, 10:11 PM
John
 
Posts: n/a
Default

Restraint in the face of an insult. You must be a good person no matter what
grade license you hold. I'm impressed...

73 de John, ks4xn

"Charlie" wrote in message
...
Hi Jim and thanks for the reply. It is more than just a numbers thing. The
ICOM website says to use a buffer if you are using a "non-Icom linear".
They don't bother to specify which non-Icom amps need a buffer . Obviously
the specs for each certain ly indicate no need. I have had some hams email
me saying to use a buffer "just in case". I suppose it couldn't hurt.

Good luck on the license upgrades... 73 / DX

--

Charlie
Ham Radio - AD5TH
www.ad5th.com
Live Blues Music
www.492acousticblues.com




"Jim Phelps" wrote in message
...

"Charlie" wrote in message
...
Using an ICOM 746 Pro with an AL-80B amp. According to their respective
manuals the AL-80B sources +12vdc at 100mA and the 746Pro can sink a max
of
+16vdc at 500mA.

QUESTION:
Do I need an amplifier keying buffer according to the above specs? My
research shows primarily these devices are for new rigs keying older
amps.
The Icom site recommends an interface for "all non-Icom amplifiers" but
in
the case of the above specs it appears to me there is already a 4 volt
and a
400mA "buffer" of sorts. The demands of the 80B are well inside the
capabilities of the 746 Pro. Right?

I'm not trying to save $50 or so but if the specs are right I don't need
it.
My rig is new and I have about 300 qsos so far which amount to at least
1000+ successful amp keying events.

--

Charlie
Ham Radio - AD5TH
www.ad5th.com
Live Blues Music
www.492acousticblues.com



You're an Extra and need to ask this? Come on, I've only (previously)
held a Tech Plus and know that 12V is less than 16V and 100ma is less
than 500ma! Man, when I go to take my elements I just may go straight to
element 4 - just for fun!





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