Central Idaho Amateur
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Configuring an ALE station with the Icom IC-F8101 Elecraft KPA-500 Elecraft KAT-500
Configuring an ALE station with the Icom IC-F8101 / Elecraft KPA-500 / Elecraft KAT-500

Configuring an ALE station with the Icom IC-F8101 / Elecraft KPA-500 / Elecraft KAT-500
7 August 2017
Author: Ray Montagne (W7CIA)
Table of Contents

A .pdf version of this document can be downloaded by clicking here.

Revision History

17 April 2017 Add the ALE Station Behavior section.


The author assumes no liability for anyone using this reference. You, the reader, must assume all liability should you apply the procedures, circuits and connections described within this document.


This article intends to provide information on how to configure an Automatic Link Establishment (ALE) station, using the Icom IC-F8101-3X, the Elecraft KPA-500 amplifier, and the Elecraft KAT-500 auto-tuner. It is possible to configure the IC-F8101-3X to properly drive the KPA-500, and it it is also possible to configure the Elecraft equipment to emulate an Icom tuner, such that tuning will occur on a transition to a new channel within an ALE scan group when calling, sounding, or receiving an ALE link request.

Tasks required to configure an ALE station with this equipment will include:

This station configuration can be made to work quite well with ALE. There are some compromises that need to be made during the configuration of the IC-F8101-3X in order to keep the power level at a reasonable setting for high duty cycle transmissions, such as ALE, which will also impact the output power levels for voice communications.

Service Menu Configuration of the IC-F8101-3X

You will need to enter the IC-F8101-3X service menu in order to reduce the MID power level settings from the factory setting of 50-Watts, to approximately 27-Watts to drive the Elecraft KPA-500 amplifier.

Before making this adjustment, you should connect the IC-F8101-3X antenna connector, through a power meter, to a suitable 50ω dummy-load, and configure the IC-F8101-3X for MID power operation.

It is also recommended that you record the value of the factory settings prior to changing any setting via the service menu so that you will be able to restore the original settings if needed at some point in the future.

To enter the service menu on the Icom IC-F8101-3X, you will need to perform the following sequence:

  1. Turn OFF the transceiver power, if the transceiver is powered ON.

  2. While holding , hold the button to power up the F8101.

  3. Press the (lower right corner) repeatedly until ABC appears at upper right, and then enter SX-. This is done by pressing 7 PRS key 3-times to enter S, the 9 WXY button 2-times to enter X, and the * &? button 21-times to enter -.

    NOTE: The key sequence to enter the service menu on the IC-F8101-3X does not function 100 percent of the time. You may have to make multiple attempts to successfully enter the service menu. Persistence pays off.

  4. Press the MGR twice (ABC changes to 123), then press 3500 and the CK MRK key.

  5. Press and hold X key to change the display to the Main menu.

  1. Scroll down to Set Mode (7/8) the CK MRK key.

  2. Scroll down to Factory (7/16) and press the CK MRK key.

  3. With Simple selected, press the CK MRK key.

  1. Scroll down to TX Middle Power and press and hold the CK MRK key to enter data-entry mode.

  2. Use the down-arrow button to reduce the TX Middle Power value to a value that results in an acceptable drive level for the KPA-500 amplifier. I used a value of 85 to achieve a drive level of 25-Watts.

    NOTE: A drive level of 25-Watts results in approximately 400-Watts output from the KPA-500 during ALE digital tansmissions. This, in my opinion, is a bit on the high side. A more reasonable goal would be to achieve 250-Watts output from the KPA-500 durimng ALE digital transmissions while achieving 500-Watts output for voice transmissions. The IC-F8101-3X includes a DATA Power Ratio setting that is located within the Detail section of the Factory settings. It may be that the desirable output power levels can be achieved by adjusting this value, however, I was unable to obtain the results that I wanted to achieve and left this setting at the factory value. Caution is advised here. The Elecraft amplifier protects itself quite well, but there isn't anything to be gained by abusing the equipment.

  1. Press the X key to exit data-entry mode.

  2. Press the X key to exit to the Setmode menu.

  3. Press the X key to exit the Setmode menu.

NOTE: If the key sequence used to enter the service menu does not work, power down the radio and try again. Experience shows that it may take more than one attempt to successfully enter the service menu.

The following table shows power settings applied to the MID value in the service menu and the measured output power (confirmed on two different radios):

60 10
75 18
85 25
90 27
111 45

Anyone applying changes to the IC-F8101-3X should, of course, verify the settings on their radio with a power meter and dummy load.

Equipment Connections

The Elecraft KAT-500 Auto-Tuner is able to respond to Icom tuner control signal sequences. Further, when properly connected, the KAT-500 will block the keying signal from activating the KPA-500 amplifier in the presence of high VSWR. Combined, these two features make the KPA-500 and KAT-500 ideal candidates for increasing the power output of the IC-F8101-3X in support of ALE operations.

An overview of these connections has the IC-F8101-3X RELAY signal (i.e. push-to-talk output, grounded when keyed), taken from the 15-pin DSUB ACC connector, to drive the KEY IN signal at the KAT-500 auto-tuner. The KAT-500 auto-tuner includes an internal relay that will block the KEY OUT signal during tuning or when a high VSWR is present. The KEY OUT signal from the KAT-500 is routed to the PA KEY signal on the KPA-500 amplifier. The START and KEY lines, taken from the IC-F8101-3X 9-pin DSUB ATU connector, are routed to the KAT-500 auto-tuner's Icom compatible tuner control input signals at the 3.5mm jack at the back of the KAT-500.

A facsimile of figure 3 from the KAT500 Owners Manual - Rev C5, modified to depict the IC-F8101-3X, is shown below:

A schematic of the required connections, including the wiring of a female 6-pin Mini-DIN connector to interface a SignaLink USB, is shown below:

NOTE: The above schematic includes interfacing of a SignaLink USB as Icom does not provide a Mac OS X compatible USB driver for the USB CI-V interface. Keying must be performed externally in such instances, and the SignaLink provides the required functionality.

The following is a connector reference from the IC-F8101-3X manual:

Elecraft KAT-500 Utility Configuration for ALE
  1. The KAT500 auto-tuner is shipped with a USB interface cable. This cable has a stereo 3.5mm plug on the end opposite of the USB connector. Install this cable on the computer and the PC DATA connector at the rear of the KAT-500 auto-tuner.

  2. Power up the KAT-500 auto-tuner.

  3. Launch the KAT500 Utility and select the proper target port to communicate with KAT-500 auto-tuner.

  4. Click on the Test Communications button to verify that the cable and port selections are functional. Then dismiss the test status dialog box by clicking on the OK button.

  1. Select the Configuration tabbed window and then click on the Edit Configuration... button.

  2. The default settings will show a configuration the following:

  1. Click on the Optimize for KPA500 button, and then click on the Apply button.

  2. Select the Tune on QSY tabbed window. Un-check the Memory Recall Tone on QSY in Mode AUTO button and then click on the Apply button. This operation is performed to prevent the auto-tune sequence from being tripped on small changes in frequency. Both the KAT500 and KPA500 can be fooled into interpretting that a frequency change has occurred during digital transmissions. This change provides some margin of relief from this behavior during ALE digital transmissions.

    See the section on Issues using the Elecraft KAT-500 & KPA-500 below for more information on equipment behaviors related to digital transmissions.

  1. Select the VSWR Thresholds tabbed window, and then increase the value in the Bypass text field from the default of 1.19 to 1.5. Click on the Apply button. Increasing this value will provide a further margin of relief from having the auto-tune sequence triggered by digital transmissions.

  2. Quit the KAT500 Utility.

Tuner Memory

Select the ALE Network in the Icom IC-F8101-3X that you intend to use, and perform a sounding. This operation is performed to get the KAT-500 to perform an auto-tune sequence on each of the channels that are contained in the ALE Network so that the auto-tune settings can be pulled from memory during later use. Subsequent use of the ALE Network channels will then result in very fast tuning and will not adversely impact the ALE dwell time.

Note that if you are using another radio service, such as MARS or USCG Auxiliary, there may be restrictions on when you are allowed to perform a sounding. You can accomplish the same goal by simply iterating over each channel in the ALE Network and use the PTT-Tune (i.e. hold the microphone push-top-talk depressed until the auto-tune sequence completes) to accomplish the same goal without actually performing a sounding.

The auto-tuning sequence of memorizing the auto-tuner settings for each channel in the ALE Network, can be performed with the KPA-500 amplifier either on or off. If the KPA-500 amplifier is turned on, you should not observe any keying of the amplifier during the auto-tune sequence. Once the auto-tune sequence is completed, any subsequent transmission, if the auto-tuner tune sequence resolved to an acceptable VSWR, should result in keying of the KPA-500 amplifier.

Your station should now be ready for ALE operations. If the KPA-500 amplifier is not on, turn it on, and make a test link with another ALE station to assess operation. Again, during the auto-tune sequence you should not observe keying of the KPA-500 amplifier, but subsequent transmissions, including an ALE calling sequence, should key the KPA-500.

Issues using the Elecraft KAT-500 & KPA-500

Both the KAT-500 and KPA-500 have internal built-in methods of determining frequency. These mechanisms can make an incorrect frequency determination during digital transmissions. Of the digital modes used, the MT63-2KL mode has been observed to, on occasion, result in an incorrect determination of frequency, and this will can result in the tuner going into an auto-tune sequence and the amplfier moving down one band from the actual band of operation (e.g. a move from 5 MHz to 3.5 Mhz when operating MT63-2KL on 5 MHz) during the digital transmission.

This behavior has been observed by two separate radio facilities (one in Alabama and one in Idaho) that are equipped with the KPA-500. These observations were also made prior to installing the ATU cabling described in this article. After installation of the ATU cabling, the downward change of band on the KPA-500 has still been observed.

The KPA-500 amplifier has several methods of determining operating frequency, including:

If the binary method provided a higher priority than the internal frequency selection, it would be possible to implement an embedded microcontroller solution to provide the binary data based on Icom CI-V data and override the adverse behavior that results from digital transmissions. A hexadecimal switch was interfaced to the binary input on the back of the KPA-500 amplifier, and the KPA-500 was then configured for BCD frequency detection in order to determine if the BCD input has a higher priority than the frequency detection. However, the very first MT63-2KL transmission made in this configuration resulted in the amplifier moving down one band from the actual band of operation. This demonstrates that the internal frequency detection has a higher priority than the binary frequency signaling method, and negates any possibility of an external work around using the binary frequency data input to the KPA-500.

Additional expeiriments to deterimine if the Icom analog band data, or the radio data interface have a higher priority than the internal frequency detection have not been attempted as of this writing. It is not known if those frequency detection methods would provide an option for implementing an external work-around. If the internal frequency detection has higher priority than these methods, no external work-around would be possible.

Issues using the Icom IC-F8101-3X
Icom IC-F8101-3X USB Device Descriptors

The following is a dump of the IC-F8101-3X USB Audio device descriptor (the interface descriptors have been omitted for brevity):

    Device Descriptor   
        Descriptor Version Number:   0x0110
        Device Class:   0   (Composite)
        Device Subclass:   0
        Device Protocol:   0
        Device MaxPacketSize:   8
        Device VendorID/ProductID:   0x08BB/0x2901   (Texas Instruments Japan)
        Device Version Number:   0x0100
        Number of Configurations:   1
        Manufacturer String:   1 "Burr-Brown from TI              "
        Product String:   2 "USB Audio CODEC "
        Serial Number String:   0 (none)
        Number of Interfaces:   4
        Configuration Value:   1
        Attributes:   0xC0 (self-powered)
        MaxPower:   0 ma

The following is a dump of the IC-F8101-3X USB Serial A interface:

    Device Descriptor   
        Descriptor Version Number:   0x0110
        Device Class:   0   (Composite)
        Device Subclass:   0
        Device Protocol:   0
        Device MaxPacketSize:   64
        Device VendorID/ProductID:   0x10C4/0xEA60   (Silicon Laboratories, Inc.)
        Device Version Number:   0x0100
        Number of Configurations:   1
        Manufacturer String:   1 "Silicon Labs"
        Product String:   2 "CP2102 USB to UART Bridge Controller"
        Serial Number String:   3 "IC-F8101 33001005 A"

The following is a dump of the IC-F8101-3X USB Serial B interface:

    Device Descriptor   
        Descriptor Version Number:   0x0110
        Device Class:   0   (Composite)
        Device Subclass:   0
        Device Protocol:   0
        Device MaxPacketSize:   64
        Device VendorID/ProductID:   0x10C4/0xEA60   (Silicon Laboratories, Inc.)
        Device Version Number:   0x0100
        Number of Configurations:   1
        Manufacturer String:   1 "Silicon Labs"
        Product String:   2 "CP2102 USB to UART Bridge Controller"
        Serial Number String:   3 "IC-F8101 33001005 B"
ALE Station Behavior

During scanning, when no call is being received, no auto-tunning occurs.

Circumstances where auto-tuning will occur include:

  1. When the IC-F8101-3X issues an auto-tune sequency by sending a START signal via the ATU connector
  2. When the Elecraft KAT500 observes, during transmit, a frequency change of greater than 1%
  3. When the Elecraft KAT500 observes, during transmit, a high VSWR.

The expected behavior, in all cases, is that the IC-F8101-3X will issue a START signal, upon moving channels, to initiate an auto-tune cycle. The auto-tuner will, in response to receiving the START signal from the IC-F8101-3X, initiate an auto-tune cycle by asserting the KEY signal back to the IC-F8101-3X via the ATU connector. When the auto-tune cycle has completed, the auto-tuner will negate the KEY signal. The IC-F8101-3X will then re-key the transmitter to perform either an ALE transmission, voice transmission, or transmission of another appropriate mode to convey information for which the transmission was originally initiated.

If the IC-F8101-3X properly issues the START signal as indicated in A above, then items B and C should not need to occur. Items B and C will occur in the abence of A, and provide protection against high VSWR operation. However, if A does not occur, the ALE dwell time may be adversely impacted by the tune cycle as a tune cycle that is initiated by B or C is asynchronous to the normal sequence that should occur upon initiating transmission on a new channel.

When moving to a new channel and initiating an ALE digital transmission, the expected sequence is as follows:

  1. Radio moves to new channel
  2. Radio initiates auto-tune cycle by issuing START
  3. Tuner asserts KEY on the ATU connector and performs auto-tune sequence
  4. Radio keys transmitter, at reduced power, with a carrier to support auto-tune sequence
  5. Tuner senses radio keying via the RELAY signal on the ACC connector, and inhibits the keying signal to the amplifier
  6. Tuner negates KEY on the ATU connector upon completing auto-tune sequence
  7. Radio un-keys
  8. Radio re-keys
  9. Tuner senses radio keying via the RELAY signal on the ACC connector, and forwards the keying signal to the amplifier
  10. Radio transmits ALE digital transmission
  11. Radio un-keys

When receiving an ALE call, I have observed instances where the radio does not issue an auto-tune prior to sending a digital transmission in response to the ALE call. When this occurs, the IC-F8101-3X has been observed to not issue a START to the auto-tuner. Further, when the digital transmission occurs that responds to the ALE call, the KAT500 will observe that a frequency change of greater than 1% has occurred, or that a high VSWR has occurred, and will initiate an auto-tune sequence on its own. This behavior does not always occur, as I have also observed instances where the IC-F8101-3X does issue a START to initiate auto-tuning prior to answering an ALE call. This issue is limited to receiving a call only and does not occur when issuing a call. This observation has been forwarded to Icom.

ALE Performance

The station configuration here includes a 184 foot balanced terminated folded dipole. This antenna is broadband, and exhibits a VSWR of less than 2.7:1 from 1.8 to 40 MHz. My use of the KAT-500 intends to optimize matching, but the tuner requirements, with this small mismatch, are fairly meager (and not strictly necessary above 3.5 MHz).

ALE operation will now need to have the IC-F8101-3X configured to the MID power setting so that an acceptable drive level is presented to the KPA-500 amplifier.

With the equipment connectiosn and configuration described above, I have been seeing acceptable performance using ALE. Received ALE calls will result in very fast memory tuning. Only on occasion does ALE result in an extraneous auto-tune sequence, and this may also result in a related fault on the KPA-500 amplifier. These appear to be rare, and are somewhat frequency dependent. My station has the IC-F8101-3X configured with a total of seven ALE networks, supporting both Amateur Radio and non-Amateur Radio services, and only a few channels within these ALE networks appear to consistently exhibit an issue. It is possible, since these network channels have other network channels that are near but do not exhibit issues, to simply remove the misbahving channels from the ALE network. I have not found it necessary to do so.

There are other issues with the IC-F8101-3X that preclude unattended station operation. My radio is a F8101-33, and some differences in behavior have been observed when comparing the F8101-31 to the F8101-33. With the F8101-33, if another station establishes an ALE link to my station and then the other station terminates the ALE link, my F8101-33 will not resume ALE scanning. The F8101-31 appears to resume under the same conditions. Attempts to resolve this behavior with Icom are on-going.

If the Icom IC-F8101-33 ALE link / unlink issues and the KPA-500 / KAT-500 frequency detection issues can be resolved, this configuration would be absolutely perfect. Lacking resolution of these issues, performance is good, and for an attended station, quite nearly perfect.

I hope this information has been useful to other users of this equipment.

73, Ray Montagne (W7CIA)

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