[aprssig] Thd72a power

[Steve Noskowicz]

Dale has it correct.

Kenwood [generally] designs their HTs as follows  (the F6 was/is an exception as its adapter is quite beefy).

  The external power jack DISCONNECTS the battery from the radio and runs the radio directly, therefore an external supply *MUST* be able to supply the full radio current drain, be it Rx, Rx+TNC, or Tx.
  The external power jack also goes through a CHARGE REGULATOR that charges the battery, from whatever supply is plugged into this jack.  THEREFORE, this external supply must be capable of running the radio *and* charging the battery. 

  Kenwood provides an external AC power adapter (a wall wart to some of us) that *only* has enough current capacity to charge the battery.
  Kenwood also supplies a DC adapter for auto use.  It can handle the full current of running the radio...and charging the battery, so it does allow full operation of the radio.

SO...
  The external supply can only supply the current that it can supply.
  If that external supply can supply the required current, you can receive and/or transmit.  If it can not supply the current you ask it to (from the radio) the voltage will drop and the radio may reset; OR the external adapter may blow its fuse; or may blow itself up.

--
 73, Steve, K9DCI   USN (Vet) MOT (Ret) Ham (Yet)
--
I served during the cold war, so you can be served a cold one.

--- On Sun, 1/16/11, DALE  wrote:

> The wall wart designed to charge the
> battery only. The wall wart is a battery charger not a power
> supply.
> It would cost a lot more to supply a full 2 amp power
> supply.
> When external power is plugged it it disconnects the
> battery from the radio and charges the battery. It also
> supplies power to the radio, but the battery is still not
> connected. If a 2 amp power supply is used it will charge
> the battery and run the radio at full tx.
> This is the way the engineer designed the system.
> I do not use the wall warts. I use solar batteries or small
> 2 to 3 amp 12 volt switching supplies or my vehicle. Most of
> P.S come from swapmeets for a few $$.
> I now have more than I need. Have not been able to sell any
> for a couple of years.
> Dale
> 
> ----- Original Message -----
> From: "Jordan Hayes KG6UAE" <kg6uae at arrl.net>
> To: "TAPR APRS Mailing List" <aprssig at tapr.org>
> Sent: Sunday, January 16, 2011 8:57:38 AM
> Subject: Re: [aprssig] Thd72a power
> 
> > The D7 has a rather anemic (60mA?) wall wart - it
> can't even charge
> > the battery if the receiver+TNC are on.
> >
> > Maybe the D72 has this same "feature"?
> 
> Yes, the supplied adapter is rated for .65A (er, 650mA) and
> the D7's 
> BC-17 is .7A ... neither are good enough to TX while
> charging.
> 
> /jordan 
> 
> 
> _______________________________________________
> aprssig mailing list
> aprssig at tapr.org
> https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig
> 
> _______________________________________________
> aprssig mailing list
> aprssig at tapr.org
> https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig
>