W6IWI, Tucson AZ

We moved from Arvada CO to Tucson AZ in 2021. An archive of the Colorado station is here. This page describes the current station in AZ.




Favorite band, image from the cover of a recent CRHS Journal, an old Schlitz magazine ad, Solar-Terrestrial Data showing conditions for HF and VHF bands and the MUF for Boulder CO, something about FT8, the W6IWI QSL card, view of W6IWI Mobile. The Optimal Working Frequency is about 0.85 times the Maximum Usable Frequency.

Search W6IWI:

The call letters W6IWI were first used by Kauko Hallikainen in the 1930s (1933 license, 1937 ARRL membership). See the 1934, 1936, 1937, and 1938 Amateur Radio Callbook. The 1930s QSL card was similar to that shown above (I may still have one of the originals somewhere). By 1952, the call had been reassigned to Carson Donaldson in Inglewood CA. He held it through 1977. I acquired the call in 2016. Prior to that, I held the call WA6FDN, and prior to that, WN6FDN. The WA6FDN license was first granted in 1969, with WN6FDN in 1968. WA6FDN shows up in the Summer 1969 Callbook. In December 1969, I took the exam for the First Class Radiotelephone License with Radar Endorsement at the FCC office in San Francisco. That license was later replaced by the FCC with the General Radiotelephone Operator's License. NL7XM offers a great service. He has over 100 years of Radio Amateur Callbooks and will find the first appearance of your callsign in the Callbook. For a reasonable cost, he'll provide certified copies of these pages verifying that the callsign was held by the particular person on this date. This is what he sent me for WN6FDN and WA6FDN.

WN6FDN started with a Heathkit DX-60 transmitter and a National NC-300 receiver running CW on HF. WA6FDN used a Viking Ranger transmitter running AM, CW, and RTTY on HF. RTTY used a Teletype model 15 printer (also see a slow motion video of a model 15 in operationg), and a model 14 typing reperf and transmitter distributor. W6IWI now uses an SEA 245 with a Dentron Clipperton-L amplifier running RTTY, CW and SSB into a Zero Five 30 Foot Flagpole Antenna. VHF and UHF FM are covered with a Baofeng UV-5R and a Wouxun KG-UV-6X. The Wouxun KG-UV-6X normally drives an outside vertical antenna at home. Mobile info is here.

HF Station Details

Click in a box in the block diagram for more details.

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Maximum Usable Frequency (16.64 MHz at 02 Mar 2024 0400 GMT)

Now and then the MUF data feed is lost. When that happens, the chart below says "Cannot read properties of undefined (reading 'length')".
The graph below plots the Boulder CO MUF and OWF over time (times are local at the browser). Data courtesy of Paul N0NBH. The MUF is the maximum frequency that can be used over a 3,000 km path centered on Boulder CO. The optimal working frequency is 0.85 times the MUF.

The graph shows the MUF and OWF for the past two days. Drag right to see previous values. Use the mouse scroll wheel to zoom in and out. Right click to get back to the original view.

W6IWI HF Activity

The table below shows recent contacts logged on qrz.com.

RBN Report

The table below is generated by a PHP script that pulls JSON data from the Reverse Beacon Network, parses it, calculates distance and bearing based on latitude and longitude, then shows data for the last 100 spots. Frequency changes greater than 1 kHz or time changes greater than 1 hour are shown in bold. The Rx links link to the QRZ page for the station. The SNR links link to a graph of signal to noise ratio versus time for that receiver, mode (CW or RTTY), and band (data limited to 100 spots from RBN)

The background color is green if the distance is greater than 3,000 miles. The Relative Distance column has a * for every 200 miles.


RBN Data for W6IWI, lat/long 32.233624, -110.870743 as reported by RBN.

TimeRxFreq (kHz)SNRModeSpeedRx LocationDistance and BearingRelative Distance
0356z 02 MarAA0O 7046.0 5 dB CW15 wpmSaint Petersburg, FL2756 km (1712 miles) at 93 degrees********
0332z 02 MarKM3T 7045.0 20 dB CW15 wpmAmherst, NH3617 km (2248 miles) at 59.6 degrees***********
0331z 02 MarW4AX 7045.0 9 dB CW15 wpmBall Ground, GA2467 km (1533 miles) at 77.9 degrees*******
0331z 02 MarW4AX 7045.0 9 dB CW15 wpmBall Ground, GA2467 km (1533 miles) at 77.9 degrees*******
0331z 02 MarKM3T-3 7045.0 20 dB CW15 wpmAmherst, NH3617 km (2248 miles) at 59.6 degrees***********
0331z 02 MarWE9V 7045.0 27 dB CW15 wpmBristol, WI2309 km (1435 miles) at 53.7 degrees*******
0327z 02 MarKP3CW 7045.0 23 dB CW16 wpmSan Jan, PR4724 km (2935 miles) at 97.9 degrees**************
0327z 02 MarK7MJG 7045.0 18 dB CW15 wpmPhoenix, AZ162 km (100 miles) at 317.9 degrees
0327z 02 MarW6YX 7045.0 37 dB CW16 wpmStanford, CA1182 km (734 miles) at 302.2 degrees***
0327z 02 MarK9LC 7045.0 21 dB CW15 wpmRockford, IL2227 km (1384 miles) at 53.7 degrees******
0327z 02 MarWA7LNW 7045.0 42 dB CW15 wpmWashington, UT595 km (369 miles) at 337.3 degrees*
0327z 02 MarW3OA 7045.0 11 dB CW15 wpmMooresville, NC2774 km (1724 miles) at 74.1 degrees********
0257z 02 MarKH6LC 14083.9 31 dB RTTY45 bpsKeaau, HI4652 km (2891 miles) at 264.3 degrees**************
0257z 02 MarKM3T 14083.9 23 dB RTTY45 bpsAmherst, NH3617 km (2248 miles) at 59.6 degrees***********
0256z 02 MarWZ7I 14083.9 16 dB RTTY45 bpsPipersville, PA3304 km (2053 miles) at 63.8 degrees**********
0256z 02 MarVE7CC 14083.9 20 dB RTTY45 bpsMaple Ridge, BC2120 km (1317 miles) at 336.1 degrees******
0256z 02 MarW3RGA 14083.9 23 dB RTTY45 bpsSunbury, PA3176 km (1973 miles) at 62.6 degrees*********
0256z 02 MarAC0C-1 14083.9 50 dB RTTY45 bpsLouisburg, KS1632 km (1014 miles) at 59.6 degrees*****
0256z 02 MarWC2L 14083.9 28 dB RTTY45 bpsNiskayuna, NY3434 km (2134 miles) at 59.4 degrees**********
0256z 02 MarWV4P 14083.9 19 dB RTTY45 bpsSavannah, TN2109 km (1310 miles) at 74.6 degrees******
0256z 02 MarK9LC 14083.8 14 dB RTTY45 bpsRockford, IL2227 km (1384 miles) at 53.7 degrees******
0256z 02 MarWE9V 14083.8 33 dB RTTY45 bpsBristol, WI2309 km (1435 miles) at 53.7 degrees*******
2207z 01 MarWC2L 14083.9 18 dB RTTY45 bpsNiskayuna, NY3434 km (2134 miles) at 59.4 degrees**********
2206z 01 MarW3RGA 14083.8 14 dB RTTY45 bpsSunbury, PA3176 km (1973 miles) at 62.6 degrees*********
2206z 01 MarWZ7I 14083.9 14 dB RTTY45 bpsPipersville, PA3304 km (2053 miles) at 63.8 degrees**********
2206z 01 MarW6BB 14083.9 23 dB RTTY45 bpsBerkeley, CA1213 km (754 miles) at 304.4 degrees***
2206z 01 MarW6YX 14083.8 41 dB RTTY45 bpsStanford, CA1182 km (734 miles) at 302.2 degrees***
2206z 01 MarKE3BK 14083.8 26 dB RTTY45 bpsMountain House, CA1149 km (714 miles) at 305.3 degrees***
2206z 01 MarWE9V 14083.8 25 dB RTTY45 bpsBristol, WI2309 km (1435 miles) at 53.7 degrees*******
2206z 01 MarAC0C-1 14083.9 39 dB RTTY45 bpsLouisburg, KS1632 km (1014 miles) at 59.6 degrees*****
2206z 01 MarN6TV 14083.9 28 dB RTTY45 bpsSan Jose, CA1141 km (708 miles) at 302.1 degrees***
2126z 01 MarNU6XB 14083.9 15 dB RTTY45 bpsBerkeley, CA1213 km (754 miles) at 304.4 degrees***
2125z 01 MarKE3BK 14083.8 24 dB RTTY45 bpsMountain House, CA1149 km (714 miles) at 305.3 degrees***
2125z 01 MarW6YX 14083.8 37 dB RTTY45 bpsStanford, CA1182 km (734 miles) at 302.2 degrees***
2125z 01 MarAC0C-1 14083.9 41 dB RTTY45 bpsLouisburg, KS1632 km (1014 miles) at 59.6 degrees*****
2125z 01 MarN6TV 14083.9 26 dB RTTY45 bpsSan Jose, CA1141 km (708 miles) at 302.1 degrees***
2125z 01 MarW6BB 14083.9 29 dB RTTY45 bpsBerkeley, CA1213 km (754 miles) at 304.4 degrees***
2125z 01 MarWE9V 14083.8 30 dB RTTY45 bpsBristol, WI2309 km (1435 miles) at 53.7 degrees*******
2125z 01 MarWC2L 14083.9 17 dB RTTY45 bpsNiskayuna, NY3434 km (2134 miles) at 59.4 degrees**********
2125z 01 MarK9LC 14083.8 15 dB RTTY45 bpsRockford, IL2227 km (1384 miles) at 53.7 degrees******
1828z 01 MarNU6XB 14083.9 9 dB RTTY45 bpsBerkeley, CA1213 km (754 miles) at 304.4 degrees***
1828z 01 MarKH6LC 14083.9 15 dB RTTY45 bpsKeaau, HI4652 km (2891 miles) at 264.3 degrees**************
1828z 01 MarKE3BK 14083.8 26 dB RTTY45 bpsMountain House, CA1149 km (714 miles) at 305.3 degrees***
1828z 01 MarWV4P 14083.9 13 dB RTTY45 bpsSavannah, TN2109 km (1310 miles) at 74.6 degrees******
1827z 01 MarN6TV 14083.9 28 dB RTTY45 bpsSan Jose, CA1141 km (708 miles) at 302.1 degrees***
1827z 01 MarW6BB 14083.9 28 dB RTTY45 bpsBerkeley, CA1213 km (754 miles) at 304.4 degrees***
1827z 01 MarWE9V 14083.8 21 dB RTTY45 bpsBristol, WI2309 km (1435 miles) at 53.7 degrees*******
1827z 01 MarAC0C-1 14083.9 32 dB RTTY45 bpsLouisburg, KS1632 km (1014 miles) at 59.6 degrees*****
1827z 01 MarW6YX 14083.8 39 dB RTTY45 bpsStanford, CA1182 km (734 miles) at 302.2 degrees***
1752z 29 FebKE3BK 14083.8 22 dB RTTY45 bpsMountain House, CA1149 km (714 miles) at 305.3 degrees***
1752z 29 FebWV4P 14083.9 14 dB RTTY45 bpsSavannah, TN2109 km (1310 miles) at 74.6 degrees******
1751z 29 FebAC0C-1 14083.9 30 dB RTTY45 bpsLouisburg, KS1632 km (1014 miles) at 59.6 degrees*****
1751z 29 FebWE9V 14083.8 22 dB RTTY45 bpsBristol, WI2309 km (1435 miles) at 53.7 degrees*******
1751z 29 FebVE7CC 14083.9 15 dB RTTY45 bpsMaple Ridge, BC2120 km (1317 miles) at 336.1 degrees******
1751z 29 FebW6YX 14083.8 40 dB RTTY45 bpsStanford, CA1182 km (734 miles) at 302.2 degrees***
1751z 29 FebW6BB 14083.9 30 dB RTTY45 bpsBerkeley, CA1213 km (754 miles) at 304.4 degrees***
0307z 29 FebKO7SS 7052.0 43 dB CW16 wpmMt. Lemmon, AZ23 km (14 miles) at 18.1 degrees
1704z 27 FebWA7LNW 7083.8 49 dB RTTY45 bpsWashington, UT595 km (369 miles) at 337.3 degrees*
1704z 27 FebKO7SS 7083.8 50 dB RTTY45 bpsMt. Lemmon, AZ23 km (14 miles) at 18.1 degrees
1704z 27 FebN6TV 7083.8 21 dB RTTY45 bpsSan Jose, CA1141 km (708 miles) at 302.1 degrees***
1704z 27 FebAC0C-1 7083.9 20 dB RTTY45 bpsLouisburg, KS1632 km (1014 miles) at 59.6 degrees*****
1704z 27 FebK6FOD 7083.8 27 dB RTTY45 bpsSouth Pasadena, CA706 km (438 miles) at 289.1 degrees**
1704z 27 FebW6YX 7083.8 41 dB RTTY45 bpsStanford, CA1182 km (734 miles) at 302.2 degrees***
0449z 26 FebWZ7I 7060.0 29 dB CW18 wpmPipersville, PA3304 km (2053 miles) at 63.8 degrees**********
0449z 26 FebAC0C-1 7060.0 34 dB CW17 wpmLouisburg, KS1632 km (1014 miles) at 59.6 degrees*****
0449z 26 FebWC2L 7060.0 25 dB CW18 wpmNiskayuna, NY3434 km (2134 miles) at 59.4 degrees**********
0449z 26 FebKO7SS 7060.0 40 dB CW17 wpmMt. Lemmon, AZ23 km (14 miles) at 18.1 degrees
0447z 26 FebZF1A 7060.0 24 dB CW17 wpmCayman Islands3278 km (2037 miles) at 108.8 degrees**********
0447z 26 FebW6YX 7060.0 41 dB CW18 wpmStanford, CA1182 km (734 miles) at 302.2 degrees***
0447z 26 FebKM3T-2 7060.0 30 dB CW18 wpmAmherst, NH3617 km (2248 miles) at 59.6 degrees***********
0447z 26 FebVE6WZ 7059.8 31 dB CW18 wpmCalgary, AB2196 km (1364 miles) at 353.4 degrees******
0447z 26 FebS53A 7060.0 18 dB CW18 wpmLjubljana, Slovenia9742 km (6053 miles) at 34.7 degrees******************************
0447z 26 FebWV4P 7060.0 27 dB CW18 wpmSavannah, TN2109 km (1310 miles) at 74.6 degrees******
0447z 26 FebW3LPL 7060.0 23 dB CW18 wpmGlenwood, MD3131 km (1945 miles) at 65.9 degrees*********
0447z 26 FebDD5XX 7060.0 8 dB CW16 wpmEsslingen Germany9234 km (5737 miles) at 35 degrees****************************
0447z 26 FebAA4VV 7060.0 29 dB CW15 wpmLexington, NC2834 km (1761 miles) at 73.4 degrees********
0444z 26 FebK9LC 7060.0 22 dB CW18 wpmRockford, IL2227 km (1384 miles) at 53.7 degrees******
0444z 26 FebWF7U 7060.0 30 dB CW18 wpmIssaquah, WA1944 km (1208 miles) at 334.2 degrees******
0444z 26 FebAA4VV 7060.0 30 dB CW18 wpmLexington, NC2834 km (1761 miles) at 73.4 degrees********
0444z 26 FebK5EM 7060.0 19 dB CW18 wpmSeattle, WA1969 km (1224 miles) at 334 degrees******
0444z 26 FebW3DAN 7060.0 28 dB CW18 wpmWest Middlesex, PA2775 km (1724 miles) at 60.5 degrees********
0444z 26 FebK3PA-1 7060.0 26 dB CW18 wpmTonganoxie, KS1626 km (1010 miles) at 57.4 degrees*****
0444z 26 FebND7K 7060.0 31 dB CW18 wpmWickenburg, AZ270 km (168 miles) at 319.2 degrees
0444z 26 FebWA7LNW 7060.0 35 dB CW18 wpmWashington, UT595 km (369 miles) at 337.3 degrees*
0444z 26 FebN4ZR 7060.0 31 dB CW18 wpmPhoenix, MD3175 km (1973 miles) at 65.6 degrees*********
0444z 26 FebKV4TT 7060.0 23 dB CW18 wpmNorth Myrtle Beach, SC2991 km (1858 miles) at 77.8 degrees*********
0444z 26 FebW3UA 7060.0 27 dB CW18 wpmBedford, NH3632 km (2257 miles) at 59.5 degrees***********
0444z 26 FebN2QT 7060.0 21 dB CW18 wpmForest, VA2924 km (1817 miles) at 69.9 degrees*********
0444z 26 FebS53A 7060.0 16 dB CW18 wpmLjubljana, Slovenia9742 km (6053 miles) at 34.7 degrees******************************
0444z 26 FebN9CO 7060.0 35 dB CW18 wpmSycamore, IL2242 km (1393 miles) at 54.7 degrees******
0444z 26 FebK6FOD 7060.0 28 dB CW18 wpmSouth Pasadena, CA706 km (438 miles) at 289.1 degrees**
0424z 26 FebKV4TT 7060.0 24 dB CW17 wpmNorth Myrtle Beach, SC2991 km (1858 miles) at 77.8 degrees*********
0403z 26 FebKH6LC 7060.0 21 dB CW17 wpmKeaau, HI4652 km (2891 miles) at 264.3 degrees**************
0356z 25 FebN4ZR 7060.0 31 dB CW15 wpmPhoenix, MD3175 km (1973 miles) at 65.6 degrees*********
0356z 25 FebW1NT-2 7060.0 24 dB CW15 wpmNewton, NH3665 km (2277 miles) at 59.6 degrees***********
0354z 25 FebTI7W 7060.0 32 dB CW19 wpmGuanacaste, Costa Rica3566 km (2216 miles) at 126.3 degrees***********
0353z 25 FebW8WWV 7060.0 29 dB CW17 wpmChesterland, OH2802 km (1741 miles) at 60 degrees********
0352z 25 FebWA7LNW 7060.0 13 dB CW15 wpmWashington, UT595 km (369 miles) at 337.3 degrees*
0352z 25 FebW6YX 7060.0 34 dB CW16 wpmStanford, CA1182 km (734 miles) at 302.2 degrees***
0424z 24 FebKM3T 7052.0 22 dB CW15 wpmAmherst, NH3617 km (2248 miles) at 59.6 degrees***********

The plot below shows a historic plot of W6IWI HF CW and RTTY activity.

Also see here for a graphical representation of all RBN data. There is also a new version under development that shows similar graphs but also paths between transmit and receive sites on a map.

Search RBN for Your Station

Enter your call and click Submit to see what RBN has on you. This can be useful for testing different antennae. Transmit TEST DE CALLSIGN a few times on one antenna, switch to the other, change frequency a bit (maybe 100 Hz) and transmit again. You should see spots recorded at several locations for each antenna. Compare the reported SNR to get an idea how the different antennae perform. Click Show/Hide on the right side of the results page to enable a map with grayline showing the location of the receive sites. If your site is not shown correctly, update your location at QRZ.COM. Once logged in, select your call (right side of menu bar), then Edit your call, then Map, Grid Square and Coordinate settings. RBN uses these coordinates to place your station.

NOTE: RBN only reports CQ or TEST. It does not report every QSO. Send one of the following (I use CW and RTTY) to generate RBN spots:

Also, note that RTTY is only reported if it is at "tape speed." Hand typed RTTY is not reported.

Call Sign:

You can also use the form below to get a more detailed RBN report.

Call Sign:

More RBN Fun!

HA8TKS has an interesting set of RBN utilities. For example RBN Graph shows all stations detected by RBN in the last 15 minutes on a selected band. The graph has frequency as the X axis and time (minutes ago) as the Y axis. It shows the call of each station detected. The color tells whether the station was running CW, RTTY, BPSK, beacon, or other. You can filter to use skimmers on certain continents and filter to only show stations on certain continents. Nice view of what's going on!

Voice of America Coverage Analysis Program

VOCAP for ham radio. Originally written for the Voice of America, this predicts the best frequency between two locations at a specific time. For more info, see www.vocap.com.

Find Hams in your Neighborhood

Amateur Radio License Map maps US amateur radio operators in an area centered on a call sign, grid square, zip code, or street address. Pretty neat!

The Ham Shack

Operating Position

The image at the right shows the operating position. Left to right, the following items are visible.
  • Teletype model 15 for Heavy Metal RTTY
  • Top Shelf
    • Dentron Clipperton-L HF power amplifier
    • Daiwa CN-501H RF power meter between the output of the Clipperton-L and the line to the antenna. Behind the CN-501H is an MFJ 4117 power injector to put 12VDC on the outgoing coax to drive the MFJ 998RT remote antenna tuner.
    • Above the CN-501H is a Wouxon KG-UV6X VHF/UHF handheld transceiver. It is driving an external VHF/UHF vertical antenna
  • Middle Shelf
    • Seacomm SEA245 HF transceiver control head. The transceiver itself is on a shelf under the table
    • Daiwa CN-501H RF power meter on top of the Seacomm SEA245 HF transceiver control head. This wattmeter is on the input to the Dentron Clipperton-L and after the SEA 1630 antenna tuner as shown in the block diagram above.
    • Battery operated digital clock set to UTC. Line operated clocks are often reset by RF.
    • EM63 TX Android tablet running DroidRTTY and Morse Code Reader. Driven by the Seacomm SEA245 unbalanced low level receive audio output (on the transceiver itself). This output is run through a voltage divider with a series 100k and 2.2k to ground to reduce the level down to microphone level suitable for the audio input of the tablet. See here for information on the TRRS audio connector used on tablet computers. An adapter cable similar to this adapts the tablet audio input to an unbalanced shielded line to the transceiver audio output.
  • Bottom Shelf
    • USL CM-8E cinema booth monitor. The CM-8E is across the SEA245 audio bus. The DSP in the CM-8E is configured to act as a narrow CW filter. The headphone output of the CM-8E is used to listen to the filtered audio.
  • In front of shelves
  • Netgear WN2000RPT WiFi Extender used to bridge WiFi to Ethernet equipment in shack.
  • CZUR ET18PRO scanner. Used to scan manuals for Saving History From The Dumpster.
  • Samsung 55 inch TV used as computer monitor.
  • Tecsun PL-310ET DSP-based portable multiband radio. Covers LW, MW, SW, and FM broadcast bands. Uses the SI4734 single chip receiver. Very impressive!
  • Shure 522 PTT microphone used on Zoom and similar calls.

RTTY Corner

For more on RTTY, see here.
  • Teletype model 14 Transmitter Distributor (punched paper tape reader). On top of the TD, there are a couple patch boxes. Each of these has four 1/4 inch TRS connectors in series (tip and ring connections in series, shell grounded). Each jack has a shorting switch shorting tip to ring when no plug is inserted. The back patch box is connected to the Flesher TU-170 terminal unit. The front patch box is connected to a Teletype 152950 loop supply with a series 2.2k resistor, setting the loop current at 60 mA. Each piece of Teletype equipment (TD, reperf, 15KSR) has a cable with a 1/4 inch TRS plug on it. These can be plugged into either loop (that sourced by the TU-170 or that sourced by the Teletype 152950). Each piece of equipment with the TRS plug has floating circuitry (selector magnet, keyboard, distributor, etc.) with no internal voltage source. There is no voltage on the unplugged TRS connectors.
  • Teletype model 14 Typing Reperforator. This punches "chadless" tape to be read by the TD. It also types on the tape so tapes can be read by humans.
  • Flesher TU-170 Terminal Unit (modem) with WAVE2 oscilloscope used as a tuning indicator. The TU-170 receives audio from the SEA245 transceiver audio bus. When transmitting, it drives the audio bus with Audio Frequency Shift Keyed tones (2.125 kHz mark, 2.295 kHz space) and pulls the PTT line low. The TU-170 also has an autostart switched AC outlet. The model 15 printer is plugged into this outlet so the printer motor starts when RTTY tones are received.
  • Teletype model 15KSR page printer.

Test Equipment and Parts!

Piles of stuff! Test equipment includes a digital oscilloscope, audio generator, audio THD analyser, audio voltmeter, FM modulation monitor (Belar FMM-2), antenna analyzer, regulated variable DC power supply, USB-based logic analyzer, etc. Below the desktop there are boxes of manuals to be scanned for Saving History From The Dumpster.

More Stuff!

Shelves with more supplies, equipment I designed, a Houston Instrument DMP-29 plotter, Ampex reel to reel tape recorder, and a Webcor wire recorder.

QSL Cards

I will always send a QSL card on receiving one. Recently received QSL cards are here.

RF Safety

Calculations on RF Safety are located here.