Excerpts from The DIGI_NED user manual (*)
The DIGI_NED user manual, Version: 1.00-030 Date: September 13, 2001 By: PE1MEW (pe1mew@qsl.net).
(*) Only the activated commands at ON0APR are mentioned.
Excerpts from The DIGI_NED user manual (*)The DIGI_NED user manual, Version: 1.00-030 Date: September 13, 2001 By: PE1MEW (pe1mew@qsl.net).
(*) Only the activated commands at ON0APR are mentioned.
About this manual
Preamble.
This is the DIGI_NED user manual. This manual is intended to be the reference for APRS users using the near-by DIGI_NED digipeater a
Contents of this MANUAL.
This Manual is separated in to different parts:
About this manualManual availability and version number.
This manual uses the available documentation released with the DIGI_NED executeable and source distribution. In the top part of each page you can find the version number and release date.
Disclaimer.
This manual is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Comments and contributions.
If you have any additional comments or corrections to this documentation feel free to contribute.
To verify and add your contibution stick to these little rules:
Send your comments to the DIGI_NED team: digi_ned@qsl.net
The DIGI_NED user manual
This manual is dedicated to the APRS user.
Introduction.
This manual as it lies in front of you or is on your screen is intened to be informing about the capebilities of a DIGI_NED digipeater. This type of digi can be situated in your area or QTH and probably it offers you the full range of services available in the software. And here we point at one important issue. Your neighbouring digi can be configured in many different ways. Her lies the strength of the digipeater software DIGI_NED.
What is possible in a DIGI_NED digi.
A DIGI_NED digi can do several things.
Digipeating.
The first and primary thing a DIGI_NED digi can do is digipeating. But not just simply digipeating. DIGI_NED is a very flexible configureable digipeater. a DIGI_NED digi does support:
Using digipath manipulation it is possible to create new digipeater rules or algorithems. Mainly your digi-owner will configurate the basic digipeat rules as they are published by the APRS committee.
You do not have to contact the digi about digipeating. Digipeating and the digipeater path is set in the APRS client program. For information about how to configure your APRS client we refer to the manual of your APRS client. Beacuse we do deliver a default configuration to the DIGI_NED package we can say something about digipeating:
NOTE 2: the type of routing mechanism is subject of change ! For up to date information about the routing mechanism check the APRS SIG (Special Interest Group) on http://www.tapr.org.
Generic digipeating with call substitution.
In APRS the digipeater-path is constantly manipulated. An APRS station uses generic calls out of your "via" list the digipeater path, such as 'RELAY', 'TRACE', 'WIDE' etc. This will be picked up by the digipeater, replaced by the digipeater's own call-sign and retransmitted. The clue is that an APRS station doesn't need to know which name a nearby digipeater has. The station just sends its frame with 'WIDE' in the via path and any digipeater in the area which responds to 'WIDE' will pick it up; there can be more digipeaters who do this at the same time. .
Intelligent digipeating: WIDEn-n TRACEn-n
The WIDEn-N format needs some special handling which is done by so called "intelligent" digipeaters such asDIGI_NED.
When a station starts with a digipeater like WIDE5-5 in the via path, the first "intelligent" digipeater that takes this frame will be change the call to WIDE5-4 as soon as it passes it. On the second "intelligent" digipeater it will become WIDE5-3 and so on until after the 5th digipeater the call has become WIDE5-0 (in other words WIDE5). Then the "digipeated" bit will be set (visible in most monitors by a '*' indication) and the next digipeater call in the via list will become due. TRACEn-N works similar. There is a lot to talk about this but that's out of context here.
All kind of manipulation can be done on the digipeater path, such as replacement with a completely new path, addition of digipeater calls to the via list etc.
To prevent APRS frames from 'singing around' due to faulty digipeater paths a intelligent digipeater is capeable of checking wethever a frame is repeated or not. A DIGI_NED digi uses for this two mechanisms:
Call substitution: By replacing the digipeater call or alias in the digi-path for his own callsign the digi prevents it self from transmitting a frame which it did send allready. the digi checks if his own call is in the digipath it will not transmit it again.
Duplicate checking: From every frame a DIGI_NED digi is transmitting the checksum is stored in a table. When a frame is received which should be re-transmitted it's checksum is compared to the one in the table. When there is a match the frame is already transmitted and so discarded.
MHeard service.
The MHeard serivice in DIGI_NED is the first group of queries available.
A DIGI_NED digi keeps a list of all direct heard stations in memory. The number of stored call-signs is configured by the owner.
The following commands are available:
DX broadcasts and queries.
DIGI_NED has a DX function build in.
First of all you can get distance information through queries. This works with the command ?DX. It works like ?MH - with port number or call.
The following commands are available:
DX with port number 1 returns for example the next 3 messages:
DX-P1 of all 263.3 km D0BRP DO4BH-1
DX-P1 of 24h 161,4 km DO4BH-1 PD0JBR-1
DX P1 of 1h 123.9 km PA3ESK-2 PE1ABT-15
The first is the best DX for all entries available in the MHEARD list. It shows the distance to best DX station, the call of the best DX station and second-best DX station.
The second and third lines are almost the same, but the second is for the stations received in the last 24 hours and the last for stations received in the last hour.
If there is no second best DX station then only one call is shown.
The duration over which is the DX measured (all, 24h, 1h) is specified by the digi owner.
We can zoom in on a station with "DX <call>" for example
DX PD0JBR-1
This returns:
PD0JBR-1 138.1 km bearing 026 degrees
It shows distances and bearing from the digipeater to this station. The DX <call> not only works on calls returned by DX <port> command but on all calls in the mheard list. Like MH also port 0 is accepted to mean 'any port'. If there is no distance and bearing information the returned message will say so.
When a station is received which is the 'best DX' over a period of time then is will be announced by means of a DX bulletin which can be caught by a TH-D7 or TM-D700 radio for example.
After a DX announcement has been send a new announcement it will not be send if the same station is heard again within a period of time.
APRS and DIGI_NED queries
There are 2 types of queries recognised in APRS. The first group is standarised in the APRS specifications. The second group is application dependant. In this case DIGI_NED related.
This are the queries that are standarised in APRS:
The following queries are DGI_NED related:
Information and Objects.
As an addition to the standarised APRS queries a DIGI_NED digi can be configured as a source of information. This information can be of any kind:
This image shows a sequence of a query.
Just ask the digi using your THD7 or APRS program and the info appears on your screen.
A DIGI_NED digi is able to send you information as text but can also create objects.
The object shows you where to go.
All this information is configureable. And it depends on what the owner of the digi has created what will be available.
If you don't know what is available just send the "help" query to the digi and it will guide you to the required information.
