From mboxrd@z Thu Jan 1 00:00:00 1970 From: chuck gelm Subject: Re: kenwood TM700 Date: Mon, 11 Oct 2004 11:56:48 -0400 Sender: linux-hams-owner@vger.kernel.org Message-ID: <416AAD40.90006@gelm.net> References: <200410111700.29340.alexandre.chappaz@data-tools.com> Reply-To: chuck@gelm.net Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200410111700.29340.alexandre.chappaz@data-tools.com> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: alexandre.chappaz@data-tools.com Cc: Linux-Hams@vger.kernel.org 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