Re: kenwood TM700

[chuck gelm <chuck@gelm.net>]

chappaz alexandre wrote:

>hi guys
>
>I am a newbie in ham radio, and for my job I use 2 Kenwood TM700 transceivers 
>for a numeric packet radio transmission (Kenwood TM700 has an build-in TNC),
>
> For the moment the TNC-radios are discussing in an half duplex mode - that 
>means one radio emmits a packet and stops, the second radio receives the 
>packet and answers and so on and so on... My problem is that in that case, 
>the maximum speed is  only one packet ever half second is emmited. This is 
>due (to me) to the time the radio emettor needs to bring the power up and 
>running for emitting the packet. The problem is that once the packet is sent, 
>the radio stops the emission, that  means it has to start up again for the 
>next packet. I didn't find any mode for telling the emetor to stay up even if 
>there's no packet to transmit....... So I'd like to know if someone could 
>help me eather for configuring properly the built-in TNC or to use a 
>soundcard modem in the same purpose 
>( have numeric transmission with the less delay possible in fact ).
>
>
>Thank a lot
>(sorry for the not perfect english i am french)
>Alex Chappaz
>  
>

Dear Alex Chappaz:

 I think that I understand your situation and your english is
1000 times better than my french.  ;-)

However, you did not describe your goal.  Are you trying to
increase your throughput?  It is the radio that is half-duplex
and not the TNC or computer.

 It is the TNC that is reducing the size of a packet and the
number of packets that can be sent.  The TM-700 has a
'micro' TNC and not a TNC-2 clone.  I think that it has
a limit of 128 bytes and one frame per packet.  This is
0.125 kilobytes per packet.

 A regular TNC-2 can send frames up to 256 bytes and up
to seven (7) frames for a total of 1.75 kilobytes.

 So, if you are trying to increase your data throughput,
you may need to:
Use radios capable of 'full duplex'.
Use a TNC capable of full duplex and full TNC-2 standard
 frames size and number of frames (256x7).

 Since you only mention your two radios and noboby else;
would using 802.11b devices help?

Regards, Chuck