[Amps] IC-718 and AL-811: Icom manual misleading, interface necessary according to Icom technician

[Will Matney]

I believe if it were me, and I were building transceivers, that I would  
make sure it would switch everything out there, including the oldies. That  
just sounds like an awful small amount of switching power either way it  
goes. Ameritron says its at 100 mA on their switching, and that actually  
may be a little high as I imagine it switching a 12 Vdc DPDT 10 amp  
contact relay. I know using either a 2N2222A or even a 2N3904 will switch  
those with no overloading of the transistor, they run as cool as a  
cucumber. If that little relay is that small, I would have just used one  
of those transistors in it's place, switching to ground. I think, if I  
recall, Rich Measures has a schematic on his website for converting some  
of the old amps to low voltage, low current, switching. See, to me, I dont  
think an end user ought to have to do this, it ought to be there to begin  
with in the transceiver. I'll almost bet that what they pay for that  
little relay is more than the cost of the transistors!

Best,

Will



On Fri, 04 Feb 2005 12:08:02 -0800, <gdaught6 at stanford.edu> wrote:

> Hi Will,
>
>> I wonder if you got a reply from someone that dont know what they're
>> talking about by the sounds of it. Heck, a small 2N2222A will switch
>> the  load there with room to spare.
>
> The transistor switch is what I use:  I simply installed one in my
> amplifier, so it pretty much doesn't care what the source of the T/R
> switch signal is.
>
>> Surely, they dont have the
>> switching coming  straight off an IC? I dont have a schematic of it
>> here to look at and see  what they've done, but that just dont sound
>> right. Also, if it has an  actual internal relay, even a small reed
>> type at that, it sould switch  that amount.
>
> No, it's not an IC, it's a small relay.  My (contesting) experience
> was that the contacts would begin to stick, even when switching well
> within their specified voltage & current.
>
>> When they said "either" 16
>> volts or 2 amps, but not both, is  a bunch of hogwash. It just sounds
>> to me like a ploy to get around  warranty work no matter what!
>
> I don't know.  I've had nothing but good experiences with Icom.  But
> the T/R switch output is way happier seeing my 0.6v @ 2ma load than
> it was seeing my 12V relay.
>
> 73,
>
>  George T. Daughters, K6GT
>
>
>
>
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