[aprssig] Considering buying a D7 - Some Basic Questions

[Brian B. Riley]

On Mar 28, 2008, at 11:05 AM, Jan T. Pharo wrote:
> Steve Noskowicz <noskosteve at yahoo.com>, Thu, 27 Mar 2008 21:49:41
> -0700 (PDT):
>
>> It'll be nice to have the portable APRS as well as the Sky Command
>> capabilities.  Neither the latest QST article on the (G), nor the  
>> original
>> article gave info about what is included with the radio (except the  
>> GPS cable).
>>
>> Specific questions:
>>
>> Does it have an in-radio charger?
>
> well, yes, a "wall wart" as i hear they call it in USA;
>> If so, is it a wall transformer / power supply with that really  
>> small inverted
>> (female) power plug?
>
> Yes.
>> Can the radio transmit on the above charger?
>
> No.


Not exactly correct. The coaxial receptacle on the D7 acts as BOTH the  
charging port AND external DC input port. So if you plug a 12 VDC  
power supply into the port capable of a couple hundred milliamperes  
current source, then the battery will charge and the D7 will operate.  
You may also remove the battery (to prevent overcharging) and run the  
D7 on an external supply from that same port. I have seen several D7's  
in Bob's  (APR) lab sitting in small plywood stands hooked up in that  
fashion. Myself, I have had two D7's since the first month  they came  
avaiable and use them that way all the time.

At one time I used to run my D7 on my office desk on "EL" (extra low)  
power with the Kenwood charger plugged in and my D700 i my truck in  
the parking lot setup as a digipeater. The 'net' current flow was in  
favor of actually charging.

>   After market batteries.
> I use Kenwood's AA cell holder.

The supplied Kenwood PB-39 NiCad isn't very good, most of them (at  
least on  the early models) died in not much over a year. Someone, I  
don't remember who, recommended to me the Maha PB-39H ('H" for high  
capacity) NiMH replacement. I bought a pair of them. The PB-39H is a  
lower voltage than the PB-39, 6 volts versus 9.6 volts, BUt it is  
18000 mah capacity versus 1050 mah. And they charge up on the talkie  
using the Kenwood wart or an external 12 vdc source just fine. I am on  
my second set and I have had  the current batteries for over four years

What does this difference mean. I have found that the 6 volt pack only  
puts out 3-4 watts instead of 5-6 watts of the 9.6 volts pack ....  
BUT, the almost double capacity easily doubles the usage time. At 5  
watts versus 3 watts most of them time you will never see the  
difference. I have made this recommendation to quite a number of  
people and I haven't heard of anyone who regretted  taking my advise  
to use the Maha battery.

I also have two sets of the AA holders that Jan mentioned for each of  
my two D7s.


--
cheers ... 73 de brian  riley,  n1bq , underhill center, vermont
   <http://web.mac.com/brianbr/>  Tech Blog
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