[Icom] Extra relay box to key amp

Wed, 27 Mar 2002 04:37:36 -0600

Can the serial port (DB-9 connector) of an old Panasonic '486 laptop,
i.e.Pin 4 (DTR) and pin 5 (sig ground) have enough power to drive a reed
relay?  If so, what kind?
Dave          W9LYA
What wrought doG hath?

On Wed, 27 Mar 2002 11:16:44 +0200 alexander eban
<[email protected]> writes:
>   Guys, good day to you all:
> I've been working with reed relays for a few years. Meder, Good Sky 
> and a
> few others. They usually have coils  from 5 to 12 VDC operating and 
> the most
> can handle from 250 to 500 mA minimum. Don't forget: the reed 
> contacts are
> basically a vacuum relay!!! They handle a surprising amount of 
> power, and
> the voltages range in the many tens of volts bracket! In my opinion 
> Icom
> would be hard put to get relays able to carry & mA only. It would 
> have to be
> a special, VERY special one.
>         My educated guess is that you can take the quoted 200mA 
> value as
> credible and not worry about voltages. Under these conditions we 
> never had a
> single failure in 4 years and we made 20000 motion detectors a month 
> at that
> time, each including a signaling relay of this kind.
> Alex Eban  4Z5KS
> RF Chief Engineer
> Wireless Division
> M.T.I. Computers
> Tel: +972 3 9025555ext321
> Fax: +972 3 9025051
> Email: [email protected] <[email protected]> 
> 
>         -----Original Message-----
>         From:        Larry Benko [SMTP:[email protected]]
>         Sent:        � 27 ��� 2002 4:35
>         To:        [email protected]
>         Subject:        [Icom] Extra relay box to key amp
> 
>         I am not addressing this to anyone in particular.  However
>         for those who insist on using an additional relay/keying
>         circuit because they consider themselves to be cautious,
>         be careful that the inline interface does not have too
>         much delay.  I have measured 5 different Icom rigs
>         including the 746, 756, 756pro, 765, and the 706 and
>         all the rigs closed the send relay 9 to 10 milliseconds
>         before the beginning of the RF output.  If your interface
>         adds too much delay you will be hot switching the RF and
>         causing splatter to others on the band.  By the way most
>         medium sized relays have operate times in the 8 to 10
>         millisecond range.  Be cautious if you wish but please 
> don't
>         be inconsiderate and interfere with others. 
> 
>         73,
>         Larry Benko, W0QE
>         ----
>         Your Moderator: Dick Flanagan W6OLD, 
> [email protected]
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> ----
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