Category Archives: Ham Radio

Guest Post: Review of the TYT SF-401 Plus Frequency Counter/Tone Meter

Many thanks to SWLing Post contributor, Mario Filippi (N2HUN), for sharing the following guest post:


TYT Frequency Counter/Tone Meter Review

by Mario Filippi (N2HUN)
All photos courtesy of author

Most hobbyists own some type of transceiver whether it is a handheld, mobile, or base station. Some examples are amateur radio HF/VHF/UHF transceivers, Citizen’s Band radios, FRS (Family Radio Service) and GMRS (General Mobile Radio Service) handhelds.

A useful tool for the shack or the field is a frequency counter/tone meter since it can measure frequencies and analog/digital tones from transmitters/transceivers. At times ascertaining that a UUT (Unit Under Test) such as a 2 meter handheld is transmitting accurately may be indicated due to problems communicating with other stations. In addition, if the UUT transmits a sub-audible tone (either analog or digital) to access a repeater, a frequency counter/tone meter can detect the presence and verify accuracy of the CTCSS/digital tone.

Author’s TYT SF-401Plus, includes instructions, antenna, rechargeable battery and charger/cable. Covers 27 MHz – 3 GHz

Frequency/tone meters can be purchased for less than twenty US dollars but normally do not include a rechargeable battery and BNC connector for attaching an external antenna. Having had experience with these types, the time finally came for an upgrade.

After shopping around a decision was made to purchase the Tytera TYT SF-401 Plus. This model includes an instruction sheet, antenna, internal rechargeable battery, USB charger and cable. It represents a significant improvement over my previous, inexpensive meter, as the TYT has a BNC connector to attach a larger antenna and has four control buttons on the front panel. It also has, via a system menu, options to adjust the frequency/tone offset, dimmer levels, three or four decimal display and auto power off. All these valuable features warrant a higher cost, which was about $50, but well worth it. This price fits the budget of most hobbyists. However, higher end frequency/tone meters are available and cost several hundred dollars for those requiring that level of quality.

Out of the box the TYT SF-401 Plus, when checked against an IFR FM/AM-500A communications service monitor, was right on the money as far as accuracy. Note that the IFR-500A was calibrated against a high precision internal 10 MHz crystal in an “oven” and this is my gold standard reference for frequency accuracy in my shack.

TYT accuracy checked against an IFR FM/AM-500A communications service monitor transmitting a 146.52 MHz/131.8 Hz tone. Note frequency readout to four decimal places.

Now, it was time to check typical radios around the shack using the TYT. The first radio tested for frequency accuracy was a BTECH GMRS-V1 HT which I use to communicate with the home QTH while running errands around town. See photo for results. The BTECH and TYT agreed perfectly. Note that the TYT’s display includes a battery status indicator on top left and a timer use indicator, which resets every time the TYT is turned on. If you are going to measure digital signals (not included in this review) there is an option in the Setup Menu for that. With the BTECH handheld running 2 watts the TYT could detect its’ frequency at roughly four feet away.

Confirming BTECH transmit frequency against the TYT. Output is 2 watts. TYT multicolor display is super.

For VHF/UHF operating, especially when afield with other hams or groups such as CERT (Community Emergency Response Teams), problems can ensue if one does not have the correct frequency or tone programmed, so having the TYT in your shirt pocket to confirm these parameters when trouble occurs can be a quick way to get to the problem. See photo of an Icom IC-2300H 2 meter transceiver checked against the TYT for proper offset and tone. The Icom was putting out 65 watts and a repeater with an offset of -1.3 MHz and 88.5 Hz tone was checked.

TYT confirming unusual offset (-1.3 MHz) and tone for a repeater. Icom IC-2300H was at high (65W) setting and connected to an outdoor discone antenna.

According to the instructions included with the TYT SF-401 Plus, the operating range is from 27 MHz – 3000 MHz with a note stating “27 MHz – 100 MHz it can not be guaranteed and the corresponding normal emission appliance” which I interpret as accuracy is not guaranteed in this frequency range. Well, I checked the TYT against the IFR FM/AM-500A service monitor transmitting an AM signal on CB Channel 19, 27.185 MHz, and the TYT measured it exactly. One other important note is that according to the instructions, the tone decoder operates in the 136 MHz – 174 MHz and 400 MHz – 520 MHz frequency range. So that may limit its use in certain areas of the spectrum. One other item if interest is that the TYT has a 10 dB attenuator when dealing with high power signals.

All in all, I’m very happy with this purchase, and find the TYT SF-401 Plus useful for “first pass” troubleshooting and helpful when aligning older rigs which due to age are off frequency /tone. It definitely has a use in this shack.


Wow–what a bargain tool for the radio shack! Thank you for sharing your review, Mario.  Once again, however, you have tempted me with a purchase!  I remember when frequency counters would set you back a couple hundred bucks–it’s insane to think that you can grab one for $40-50 US shipped.

SF-401 Plus Retailers:

Note that the TYT SF 401 Plus is also marketed as the Surecom SF401 Plus:

Listen to an upcoming ARISS contact with your scanner or HT

On April 18, consider setting your scanner or handheld VHF radio to 145.80 MHz around 15:57 UTC; you may be able to hear the downlink from the International Space Station. The Amateur Radio on the International Space Station (ARISS) contact will be between between NA1SS (on the ISS) and KD2IFR at a school in Central Islip, NY.

As long as you’re within the ISS’ signal footprint (which is rather large) you should be able to easily hear NA1SS’ side of the conversation. I’ve listened to the downlink in the past using an Icom ID-51a and the super compact Yaesu VX-3R:

Click here to view on YouTube.

Click here to view on YouTube.

The frequency of the downlink will be 145.80 MHz. As the ISS climbs above your horizon, because of doppler-shift, listen on 145.805, then move to 145.80 as the ISS approaches zenith and finally move to 145.795 MHz as the ISS drops toward the other horizon. As we’ve mentioned in past posts, you’ll know when to switch frequency when the audio gets bad.

ARISS contacts happen quite frequently–I’m posting this notice because I’ve noted it in my own calendar. Check out the ARISS “Upcoming Contacts” page where future ARISS QSOs are listed. This is a great opportunity to show kids of all ages what you can hear with a modest radio!

Check out a news article about this event via the Southgate ARC:

Upcoming ARISS contact with Central Islip Union Free School District, Central Islip, NY

An International Space Station school contact has been planned with participants at Central Islip Union Free School District, Central Islip, NY on 18 April.

The event is scheduled to begin at approximately 15:57 UTC. The duration of the contact is approximately 9 minutes and 30 seconds.

The contact will be direct between NA1SS and KD2IFR. The contact should be audible over the state of New York and adjacent areas. Interested parties are invited to listen in on the 145.80 MHz downlink. The contact is expected to be conducted in English.

Welcome to the Central Islip Union Free School District – Home of the Musketeers and a proud Suffolk County, New York school system, where approximately 8,000 students in grades Pre-Kindergarten through 12 receive their formal education. Our School District’s motto is Children Our Future ~ Diversity Our Strength. The Central Islip Union Free School District is comprised of eight schools: one district-wide early childhood center, four elementary schools, two middle schools and a high school.

The Hamlet of Central Islip is a vibrant, culturally-diverse community. A suburban community with urban demographics. We are a positive and progressive school district whose teachers are dedicated to helping students achieve their maximum potential and to develop academically and socially. Our district offers an array of afterschool activities including sports, music, theatre arts and much more.

Participants will ask as many of the following questions as time allows:

1. What are the challenges of spending so many months constantly around the same people?
2. What is the best way to describe the feeling of zero gravity?
3. Have you experienced anything unexpected while in space that could not be explained?
4. Have you experienced any significant changes, either physically or emotionally, since being in space?
5. What type of robots do you use on the ISS and how are they helpful?

6. What is your advice for young people who want to become involved in programs at NASA?
7. What is the biggest challenge about being on a long duration space mission?
8. How does digestion in microgravity compare to digestion on Earth?
9. Have you experienced anything in space that has made you change your perspective on life?
10. Are there any plants aboard the ISS and if so, what’s different about how they meet their daily requirements?

11. What are the long term effects of reduced leg muscle use in long duration space travel?
12. Is your circadian rhythm affected by multiple sunrises and sunsets each 24 hour period, perhaps making it difficult to sleep for long periods of time?
13. Can you describe the types of training that prepared you for this mission?
14. Can you catch a cold on the Space Station?

15. Do the properties of light appear to be different in space?
16. Are there differences in how your body responds to physical exertion while in microgravity?
17. Would it be possible to transmit a mechanical wave on a rope onboard the space station or outside the station?
18. What are the hardest tasks to perform in space that are routine on Earth?
19. Could you blow a bigger than normal gum bubble in space?
20. Are there precautions that you take BEFORE going into space that can help to prevent bone weakness when you return?

PLEASE CHECK THE FOLLOWING FOR MORE INFORMATION ON ARISS UPDATES:

Visit ARISS on Facebook. We can be found at Amateur Radio on the International Space Station (ARISS).
To receive our Twitter updates, follow @ARISS_status

Next planned event(s):
1. King’s High School, Warwick, UK, direct via GB4KHS
The ISS callsign is presently scheduled to be OR4ISS
The scheduled astronaut is Ricky Arnold KE5DAU
Contact is a go for: Thu 2018-04-19 12:05 UTC

2. Russian school TBD
The ISS callsign is presently scheduled to be RS?ISS
The scheduled astronaut is Alexander Skvortsov
Contact is a go for Tue 2018-04-24 11:05 UTC

3. Russian school TBD
The ISS callsign is presently scheduled to be RS?ISS
The scheduled astronaut is Alexander Skvortsov
Contact is a go for 2018-04-25 08:35 UTC

About ARISS:

Amateur Radio on the International Space Station (ARISS) is a cooperative venture of international amateur radio societies and the space agencies that support the International Space Station (ISS). In the United States, sponsors are the Radio Amateur Satellite Corporation (AMSAT), the American Radio Relay League (ARRL), the Center for the Advancement of Science in Space (CASIS) and National Aeronautics and Space Administration (NASA).

The primary goal of ARISS is to promote exploration of science, technology, engineering, and mathematics (STEM) topics by organizing scheduled contacts via amateur radio between crew members aboard the ISS and students in classrooms or informal education venues. With the help of experienced amateur radio volunteers, ISS crews speak directly with large audiences in a variety of public forums. Before and during these radio contacts, students, teachers, parents, and communities learn about space, space technologies, and amateur radio.

For more information, see www.ariss.orgwww.amsat.org, and www.arrl.org.

Thank you & 73,

David – AA4KN

St. Bandon (3B7A): An all-SDR DXpedition

3B7A Antenna Layout (Source: SunSDR)

Many thanks to SWLing Post contributor, Mike Hansgen (K8RAT), for passing along this press release from SunSDR:

The 3B7A Saint Brandon team is now active from Saint Brandon and we are exited! This is the first major DXpedition that will be using only SDR transcievers in its setup.[…]

SunSDR2 Pro

Using past experience from their successful FT4TA expedition to Tromelin island and FT4JA Juan de Nova island Expedition, the experienced team lead by F5UFX Seb build their St Brandon setup around the SunSDR2 PRO transceiver, the SPE 1.3K-FA amplifier and ModMic attachable boom microphone.

3B7A will have 5 x HF stations on air simultaneously. Each station will have a SunSDR2 PRO with E-Coder hardware controller, an amplifier, and a ModMic. Logging is done using WinTest in network configuration and all stations will be able to operate CW, SSB or RTTY.

All 5 stations will have will have identical configuration from the keyboard to the amplifier. This will keep the operator focused on the pile-up and improve redundancy in case of any equipment failure.[…]

Click here to read the full article at SunSDR.

Note that I believe the January 2018 Bouvet Island (3YØZ) DXpedition would have also been one of the first major ham radio DXpeditions to use SDRs (FlexRadio SDRs). Sadly, due to weather and engine problems, 3Y0Z were not able to activate.

Shortwave Radio Recordings: Ham radio contacts between W2PVF (SK) and two Antarctic Stations, circa 1974

Palmer Station (Photo Credit: Ryan Wallace and the USAP)

Many thanks to Bill Hemphill (WD9EQD) who is one of our newest contributors at the Shortwave Radio Audio Archive (SRAA). Bill approached me at the Winter SWL Fest this year noting that he has a wide variety of radio-related audio recordings to share with the SRAA and the SWLing Post.

This week, Bill shared two fascinating tape recordings he originally acquired from an estate sale box.  These recordings were originally made in 1974 by the late Jim Hayward (W2PVF) in Absecon, New Jersey (USA) with two different ham radio stations in Antarctica.

This first recording is between W2PVF and KC4AAC of Palmer Station. The audio starts mid conversation:

Click here to download.

The second recording is between W2PVF and LU1ZE of the Argentine Antarctica Station. The operator at the microphone is W1PV. The recording even includes a phone patch:

Click here to download.

Bill, thanks so much for sharing these recordings–I thoroughly enjoyed them!

I’m so impressed with the audio and signal quality of the Antarctic stations.  In 1974, we were approaching a solar minimum in Solar Cycle 20. Still, I bet conditions were better than anything we’ve seen in over a decade!

I’m curious if any Post readers have ever made contact with either of these stations or even know the operators in the recordings? Bill notes that  Jim (W2PVF) was president of the local Atlantic City Electric Company for many years. Would be fun to share these recordings with the some of the original operators, if they’re around!

Possible First 2200-Meter Transatlantic Ham Radio Contact

(Source: ARRL News via Mike Hansgen)

In late March, Paul Kelley, N1BUG, of Milo, Maine, completed what may have been the first transatlantic 2200-meter contact by a US radio amateur under Amateur Radio rules. Signals in this part of the spectrum and lower previously have spanned the Atlantic in one direction, and Canadian radio amateurs have reported transatlantic contacts on the band dating back several years.

“To the best of my knowledge this is the first transatlantic two-way QSO from the US on 2200 meters under Part 97 operation,” said Kelley, who told ARRL that he gravitates toward the more challenging, “weak-signal” aspects of Amateur Radio and has been experimenting and DXing for 37 years now.

“2200 meters is my new passion, and I am having a lot of fun with it!” he said. I had been dreaming of — and working toward — a transatlantic QSO on 2200 meters for some time. Recently, I asked Chris Wilson, 2E0ILY, if he would be interested in trying to work me on DFCW60 mode. Chris and I have heard each other on WSPR, but he does not hear me well enough yet for a JT9 or other digital QSO. Chris agreed to try DFCW60 — dual-frequency CW, 60 second dit length.”

This was not a quick contact. It took four nights to complete, using night-by-night sequencing. Kelley called that “the minimum possible time” for such a contact, which included an exchange of complete call signs, signal reports, and acknowledgements. Kelley said they used the TMOR reporting system, borrowed from the moonbounce world.

“The QSO was completed at 0020 UTC March 28 when I received ‘R’ from Chris,” Kelley said.[…]

Click here to read the full article on the ARRN News site.