How to use LINKUp

How to use LINKUp

Usage of LINKUp is fairly straightforward and there are some powerful features provided which enable unattended operation as well as station-to-station chat.

Square One

When beginning to use LINKUp, it will be necessary to find another user to connect with. If you are monitoring one of the [watering hole frequencies] then you may see call signs in your heard list from other station conversations, message transfers, or beacons. You may select a call sign from the heard list and then use the LINKUp button to query that station for a print quality report.

The concept of the LINKUp is simple but powerful. Type a call sign into the small destination call sign field just to the left of the Blue transmit text field. Then click the LINKUp button near the top of the vertical button bar. This will compose a LINKUp frame with the source and destination call signs and then use FLDIGI to transmit it to the other station. If the station receives the frame, and it passes a CRC check for validating that it was fully and correctly recevied, the receiving station will automatically respond with a signal quality report. The signal quality report is normalized by FLDIGI to a floating point value between 0.0 and 100.0.

The Basic Scenario
The signal quality report gives the sending station an idea of how well the receiving station is printing him. At this point, if the report is poor, the sending station may choose to select another modem from the combo box at the bottom left of the Terminal tab. This will change the modem in FLDIGI. Now another LINKUp request is sent in hopes that this new modem will provide better communications. Please note, that this scenario works only if the receiving station is running RxID ON and the sending station runs TxID ON in FLDIGI. It is recommended to run both when establishing comms.

If so, the sending station may then send a short "order wire" message to the receiving station using the Blue order wire text field. He would type in his message and press the <Enter> key on the keyboard at which time, FLDIGI will send another LINKUp framed message to the receiving station. If the message is received properly (passes CRC) then it is printed on the receiving station's Yellow receive text area.

The QRU-QRV-QSL Scenario

Message FIle Staging
A station may prepare a message text file for another station by naming the text file beginning with the receiving station's call sign. If, for example, you wished to prepare a message for me, simply make a text file with the message in it using the Scratchpad tab, or your favorite software (Notepad++, Leafpad, gedit, flmsg...whatever) and save that file with a filename that begins with "AB4MW" (case insensitive). So something like "AB4MW_20160625_001.txt". Place this text file into the QRU folder in LINKUp's directory structure. That message is now "staged" for retreival by me.

Message Query Function QRU?
If I have made a LINKUp to the sending station, I can then click the QRU? button to query LINKUp if there is a message file for me. If so, the sending station will reply with QTC:1 (in our case of one message, but the numeral represents how many message files there are with my call sign).

Message Retreival Function QRV
I may now click the QRV button which instructs the sender to auto-send the first message file in the list named for my call sign. If I receive that message file and it passes CRC check, then I will reply with

QSL: AB4MW_20160625_001.txt

Message Receipt Validation
The QSL reply provides a way for the sending station to know that the message was properly received. This triggers an archive of that message to the QRV folder in LINKUp and removes it from staging. If there were more than one message staged for my call sign, then another call by me to QRV will send the NEXT message file to me. I may at any time query the sending station again with QRU? to see how many message files remain. It is possible that the sending station operator may have added a new message file while I have been transferring others, so it will be good practice to end a "session" by another QRU? to ensure that there are no remaining messages for me.

One additional step is taken after a QSL report is received. The sending station then confirms that it has archived the message. This is IMPORTANT because unless the sending station successfully receives a QSL report for a message file, IT WILL NOT BE ARCHIVED, therefore I may now know that the message was archived and may proceed to the next message query QRV. If the sending station DID NOT receive my QSL report, then I may manually send it again using the QSL button. I will then navigate to the message file I have successfully received and use that to re-send the QSL report.

Remaining Fuctions

ALLCALL simply changes the destination call sign to ALL which allows a set of stations to converse in chat mode where all stations print the message sent to ALL.

EMCON inhibits the program from sending transmit text to FLDIGI. If you were in a high energy EmComm environment and needed to step away from the radio position, this would discourage unwanted usage of FLDIGI while your attention was diverted elsewhere. If you then try to transmit, LINKUp will provide a dialog box to remind you.

DEL CALL allows the user to remove a call sign from the HEARD list (white vertical list to the right of the button bar).

SAVED opens a file dialog to the saved folder. If the user selects a text file, it's contents are transferred to the Scratchpad tab and tab focus is transferred to the Scratchpad.

EXIT closes the LINKUp program.

FILE XFER opens a file dialog and allows the user to select ANY file to be transmitted to the other station directly. This file is first compressed usign gzip compression, then Base64 encoded to limit the "alphabet" used over the air to plain text. On the receiving end, the reverse is accomplished after a CRC check and the file is written to the receiving station's received folder in the LINKUp directory structure.

The My Files Tab

The My Files tab provides a quich way to view text files without leaving the program. Simply navigate to the file and either double-click it or click the Show File button to display the contents. The contents may be transferred to Scratchpad using the button at the bottom, Send to Scratchpad. The user may refresh the file listings at any time using the Refresh File Listings button.

The Scratchpad Tab

Scratchpad is a simple text editor which provides basic text file creation and manipulation tools via buttons as well as by right click context menu in the text area. The user may also select a portion of the text in the text are and send only that text (in a LINKUp header) by using the Send Selected button. Alternately, the user may send the entire displayed text by using the Send All Text button.

The HEARD List

The White vertical list to the right of the vertical button bar will display a list of heard stations. Selecting a heard station from the list will populate the destination call sign field with that call sign. The HEARD list is saved between sessions and reloaded upon startup. The user may remove the selected call from the HEARD list with the DEL CALL button at any time.

Modem Selection Combo Box
The modem selected in this combo box is set in FLDIGI as it's currently used modem. LINKUp will track modem changes from FLDIGI to LINKUp. In this way, when another station changes the modem using TxID, that new modem will be displayed in LINKUp as well.

CLEAR Button
Clears the receive terminal area in LINKUp. It also clears the underlying input buffer.

RESET Button
If FLDIGI has been running a while with garbage text on the screen, it may be advantageous to clear it's input buffer manually in this manner. This clears the text in the FLDIGI receive area, and it's input buffer for XMLRPC.

LOG Button
Sends the receive terminal area text to a log file with today's ZULU date and clears the terminal area. A new log file is created when the ZULU day changes.

ABORT Button
Allows the user to abort a transmission by FLDIGI. In mixed mode environments, such as MARS, it is possible to signal the sending station by voice that the transmission is not being received and one may abort it to regroup and save time.

Center Frequency Label
To the right of the modem selection combo box there is a label which tracks the current position of the FLDIGI waterfall receive cursor (waterfall frequency). If FLDIGI is set in such a way as to track signals with AFC or RxID, then the center frequency may wander far afield of you your chosen center frequency. This gives the user a visual cue as to where he is actually listening in the pass band.

Recommendations for Configuring FLDIGI
Recommendations may be found on the [FLDIGI Configuration] page.

The Config Tab

See [Configuration of LINKUp]