Following the monthly club meeting we enjoyed a brief tech program on some of the incredibly affordable and indispensable tools that a radio amateur can add to their bench-testing arsenal in 2019. We focused on two main devices for this tech program:
The NanoVNA is a small form-factor vector network analyzer available from online resellers. Developed by @edy555 and ttrftech, NanoVNA brings a highly affordable vector network analyzer to the amateur radio operator. Until fairly recently, VNA’s were industrial/commercial hardware normally available only to a select few working in RF product development or maintenance disciplines.
Implementing a simple touchscreen interface, two RF ports, a USB-C charging/data port, and a thumbwheel control, the NanoVNA provides accurate, essential RF circuit data to users for less than $50 USD. Available at online resellers, the NanoVNA has been mass-produced by several Chinese manufacturers and offered to the US market at very affordable prices (some listings at a popular online auction website were as low as $17 shipped as of this writing.) Several excellent reviews have been written on the NanoVNA, but this one at RTL-SDR.com captures everything quite nicely:
The NanoVNA provides several critical functions for amateur radio operators. This list is by no means all-inclusive, but is intended to give the reader a brief idea of the capabilities of such a powerful tool:
- Antenna Analyzer (Return Loss, SWR, Smith Chart)
- Coax Cable Test Tool (Time Domain Reflectometer, Loss Calculations)
- RF Filter Tuning (Duplexer Cavities, BP/BR Filters)
- Circuit Phase Measurements
If you are an amateur operator who wants to ensure your equipment and homebrew circuits are performing at their peak, a NanoVNA is an essential piece of equipment for your shack.
The second critical amateur tool we examined was the RTL-SDR receiver:
The RTL-SDR software defined radio receiver provides the radio amateur with a high-quality 8-bit ADC radio receiver for approximately $20 USD (as of this writing.) The receiver is used in conjunction with any number of different SDR software packages with are available in one or another form for all major computer operating systems.
The RTL-SDR receiver v3.0 provides a receive bandwidth of 2.8MHz from 500kHz-1.7GHz. This allows it to receive transmissions in these and other bands:
- AM Broadcast Band
- Amateur Radio HF/VHF/UHF/SHF Bands
- US Air Band
- DoD UHF
- NOAA Weather Radio
- Amateur Radio Satellites
- FAA ADS-B (Air Traffic Transponders)
Many other services are available using software designed to support the RTL receiver. To get started discovering what you can do with your RTL receiver, start here:
Of course, you’ll have to add your own antenna system to the RTL to get peak performance, but low-cost wideband discone antennas are readily available at Amazon and eBay.
These two devices are vital tools for the amateur radio shack of 2019 and provide phenomenal capability at very low cost. Don’t delay in pickup up your 21st century shack tools today!
Since last weekend’s system upgrade, you may have noticed interference on the repeater system from Mexican taxi drivers. We believe we have narrowed down the interference to the 70cm link radio at Alamo Peak. Plans are in work to reprogram the link radios on the system this weekend to eliminate the interference.
Users of the James or Weed repeaters may also notice significant receive audio degradation from users entering the system from Alamo Peak. We believe this is due to the last minute substitution of an out-of-band link radio at James Ridge after discovering the primary link radio had experienced catastrophic failure in the PA circuit. A replacement radio is on order and the planned site visits this weekend to reprogram the link radios will also include replacing the under-performing link radio on the Alamo-James link, provided the replacement radio arrives in time.
Please note any other performance or audio issues you experience with the upgraded system and notify me via email.
As of 2000 MDT tonight, the SMRC club radio system has been upgraded at all three sites with Yaesu DR2X repeaters on 2m. The upgrade should correct the issues the system has been having with the link radio at James Ridge, and analog linking was tested across the whole system with no issues noted.
The upgrade also brings C4FM to all three repeaters sites; however, digital linking is still a work in progress. Each individual site will repeat both analog FM and C4FM transmissions, but only the analog transmissions will link to all three sites.
NOTE: As part of the system upgrade, the PL tones to access all three system repeaters has changed to 151.4 Hz. Regular users of the system will have to reprogram their radios to reflect this change.
An additional part of the upgrade was adding a PL tone on the output of each repeater. Analog FM users who do not want to listen to the audio of digital system users can simply set a PL tone of 151.4 on their radio receive, as well as transmit, and it will prevent any digital signals from breaking squelch, as digital is transmitted from the repeater with no PL tone at all. In addition, users who have a Busy Channel Lockout (BCLO) feature on their radios are encouraged to use that feature, as it will prevent analog and digital users from transmitting on top of opposite mode transmissions.
The Repeaters section of this website has been updated with the new repeater programming data, so reference that page for detailed information on system configuration.
Note any issues with the new system over the next few weeks and be prepared to discuss at the September club meeting.
Thanks to Bill, KI5J, for his assistance in getting everything transitioned to the new repeater radios, as well as the technical work behind the scenes to make it happen. Enjoy the new radios!
Several local amateur radio operators in Otero County have set up System Fusion simplex nodes utilizing the HRI-200 WIRES-X interface from Yaesu.
The HRI-200, when coupled to a compatible radio and a broadband Internet connection, provides a way for System Fusion users to connect to “nodes” and “rooms” outside the local area. Nodes and rooms are terminology used by Yaesu to denote individual and group endpoints to which users may connect using the WIRES-X system. For those familiar with Echolink terminology, WIRES-X “nodes” are similar in function to Echolink “-L” nodes and WIRES-X “rooms” are similar to Echolink Conferences, where many users may connect at once.
Thanks to implementation by Rick, N7SGT, and Justin, K5WAZ, I have been able to test various advanced features of System Fusion by accessing their HRI-200 enabled Fusion nodes from the FTM-400 radio mounted in my mobile station. The user interface of the FTM-400 makes System Fusion advanced linking a very simple and easy to implement endeavor.
Experiments I’ve conducted on air have involved remotely connecting a simplex node to rooms in Arizona, Texas, and even Moscow, Russia. In all three cases, digital audio passed over the connection seamlessly, and stations in Moscow were every bit as clear as local stations I’ve worked using C4FM. In addition to digital audio, Yaesu WIRES-X control software (which runs on a Windows computer connected to the HRI-200 interface) implements a type of digital “message board” which works similarly to an early 1990’s packet BBS system, but allows the upload/download of not only text messages, but also short digital audio messages, and even digital images to nodes and/or rooms in the system. All three types of messages are easily retrieved or uploaded using the FTM-400 WIRES-X interface.
Of the three major amateur radio digital systems I’ve used, System Fusion is by far the most user-friendly system of the three. D-STAR gateway configuration can prove a steep learning curve for new users, and that’s assuming the new user is able to successfully navigate the “registration” process to get entered into the official “Trust Server” in the first place. DMR “talkgroup” and “color” configuration is a language unto itself and presents a steep learning curve for DMR adopters. In contrast, System Fusion users will likely find using advanced features of SF systems fairly intuitive and straightforward. Backward compatibility with analog FM is also another unique feature of System Fusion hardware which may help smooth the “digital transition” for SF adopters.
Rick, N7SGT, has made his simplex node in Alamogordo available to all amateur operators. The node operates on a frequency of 146.460MHz, is operational daily from approximately 0700-2300 local time, and covers much of the Alamogordo metropolitan area. Please be courteous and drop any initiated links when concluding access of the node.
For more information on System Fusion and the capabilities it brings to your radio operations, visit the Yaesu System Fusion customer portal.
After a trial implementation with SMRC system remote linking using the AllStarLink network, some additional improvements need to be made to the system to facilitate external connectivity.
Due to the legacy configuration of the repeater system and the up/downlink configuration of the experimental AllStarLink node attached to the system, telemetry tones from the James Ridge repeater are passed over the link to Alamo Peak. The net result of this is that telemetry tones for the system are passed over remote links such as AllStarLink and Echolink, which is an undesired practice. Proper repeater system configuration is a system where each individual radio (primary or link radio) emits telemetry without associated tone encoding which prevents the telemetry from being repeated over other radios in the linked system when combined with proper CTCSS settings on other system radios.
Correcting this issue may be paired with a more advanced technological solution which enables CTCSS coding to be used to allow C4FM and analog FM users of the repeater system to both enjoy use of the system without causing unwanted end-user radio traffic to users of the opposite modulation scheme/mode. Integrating an advanced repeater controller at each site will allow multiple CTCSS tones to be used on repeater transmit based on the type of modulation used. End-users can then implement a receive CTCSS (available on virtually every modern FM transceiver) to prevent squelch break unless a received transmission is accompanied by the CTCSS tone suitable to the mode being transmitted.
This functionality is currently being implemented on the Alamo Peak transmitter in a slightly modified manner. Analog FM users who normally monitor the Alamo Peak repeater may filter out unwanted digital transmissions by setting a receive CTCSS of 151.4 Hz in additional to utilizing the normal transmit CTCSS of 151.4 Hz used to access the repeater. C4FM digital transmissions from Alamo Peak utilize no CTCSS tone, and C4FM receivers do not break squelch on receipt of analog FM signals, so mode isolation is currently possible for both C4FM and analog FM users on the Alamo Peak repeater.
Unfortunately, C4FM is currently passed over the system link to both James Ridge and Weed repeaters without the ability to CTCSS segregate those signals. The C4FM is passed through the audio section of the link radios, and as such is not decodable by other C4FM receivers, but is also unable to be filtered using CTCSS tones. As we upgrade the repeaters at James Ridge and Weed to the DR2X multi-mode repeaters, this problem will be corrected and in its final configuration, the system will facilitate co-use by both analog and digital users with minimal interference to each other.
A repeater controller which allows mode segregation via CTCSS tone will also allow the use of non-tone encoded telemetry data, which will make the implementation of analog linking services such as AllStarLink and Echolink clean and technically correct. Stay tuned as we work to implement this solution in coming months.
Join the Sacramento Mountains Radio Club for our 2019 Spring Foxhunt on Saturday, March 9th, 2019 at 10:00am beginning at the south end of Alameda Park in Alamogordo, NM.
A foxhunt is an amateur radio field exercise where a low power radio transmitter is hidden in a geographic area and “hunters” utilize radio direction finding equipment to locate the hidden transmitter. The first “hunter” to locate the transmitter wins the hunt. Foxhunts have traditionally been used by amateur radio operators as a fun way to implement a wide range of amateur radio technical skills including antenna construction, signal strength measurement, and even more advanced direction finding techniques such as time difference of arrival measurement.
The SMRC 2019 Spring Foxhunt is open to all licensed amateurs, as well as unlicensed persons wishing to participate. Unlicensed participants will not be allowed to transmit on any frequency requiring a license to do so. The Hunt Master shall act as Hunt Control and will be available to answer questions, or give clarification about the hunt rules prior to the start of the hunt.
Hunt boundaries will be anywhere within a 10 mile radius of the start point. The hunt talk-in frequency will be 147.220MHz (PL 151.4/+ offset) – the SMRC Alamo Peak repeater. This frequency may be monitored by hunters before, during, and after the hunt. All communications pertinent to the hunt will be coordinated on this frequency. Unlicensed participants will be given an alternate means (i.e. mobile phone number) to contact the Hunt Master.
The primary transmitter signal will be receivable at the starting point determined by the Hunt Master. The primary transmitter will not be activated until the Hunt Master announces the start of the hunt. The primary transmitter will operate on a frequency in the 2 meter amateur band (144-148MHz) which will be announced at the start of the hunt. The hidden transmitter’s power output level will not vary (within the unit’s capability) throughout the hunt. The transmitter(s) do not have to maintain a continuous signal output – they may be cycled on and off. The transmitter antenna may be in any configuration; however the polarization and location will not change during the hunt. Secondary transmitters, if any, will be operational on a separate frequency, which will be disclosed upon finding the primary transmitter.
All hidden transmitters will be located within 500 feet of public areas accessible by standard passenger cars with no charge for admission. Reasonable care must be taken to ensure that hunters can safely to any hidden transmitter. The Hunt Master must avoid placing any hidden transmitter near traffic or other safety hazards. Hidden transmitters may not be placed on private property without prior written approval by the property owner. Such approval must release the Sacramento Mountains Radio Club and all its members and guests from any and all liability.
The winner of the hunt is the registered person/team who finds the transmitter in the shortest amount of time. The winner also has the option to be the Hunt Master for the next SMRC Foxhunt event.
All hunters must register at the hunt start location and the registration fee is $10.
If you’ve been hearing more than the average number of DTMF tones on the repeater system lately, it’s likely because an experimental implementation of AllStarLink is now running on the SMRC linked repeater system.
AllStarLink is an analog FM linking capability which uses on-air DTMF tones to connect & disconnect from other system nodes via the internet. For those familiar with Echolink, AllStarLink provides similar functionality at a basic level, but allows some significantly more complex configurations when fully integrated. In fact, once the AllstarLink system is fully implemented, the SMRC repeater system will provide both Echolink and AllStarLink connectivity.
The experimental implementation provides basic AllStarLink connectivity. The following control codes can be used to interact with the system:
- *3 + ASL Node Number = Connect to remote node
- *2 + ASL Node Number = Connect to remote node (monitor only – no transmit)
- *1 + ASL Node Number = Disconnect from remote node
- *721 = ASL Link Radio ID
- *722 = ASL System Current Time
- *806 = Disconnect all links
Users are encouraged to test the system and provide feedback via email to my call at gmail.com. Adjustments to system audio, implementation of location announcements, periodic audio QST’s, Echolink implementation, and a nationwide VOIP autopatch are just a few of the system capabilities currently in work.
For a list of nodes to which you can connect, visit the AllStarLink node list and look for node numbers listed in green squares. A filter function at the top of the list allows you to search for specific callsigns, node numbers, and locations.
Have fun with AllStarLink, and watch this news feed as we bring more features to the system in the near future!
Come join the Club as we partner with Alamogordo Amateur Radio Club to participate in the 2019 Winter Field Day radio operating activity on Saturday, January 26, 2019 through Sunday, January 27, 2019. Winter Field Day is an annual activity which promotes amateur radio emergency preparedness by conducting radio operations under improvised field conditions during winter weather. The Alamogordo Amateur Radio Club supports this activity from their regular meeting location at the La Luz Fire Station in La Luz, NM:
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Setup for the event begins at 8:30am on January 26 at the fire station. Radio operations will commence at 12:00pm and run for 24 continuous hours. The Alamogordo club is planning on running 4 separate radios for the event on a wide variety of frequencies and operating modes. There is sure to be an operating activity of interest to all! This event is a great introduction to a broader range of radio operations for new hams or those potentially interesting in learning more about the hobby.
For more information on the local activity contact the Alamogordo Amateur Radio Club at: email@example.com
For more information on Winter Field Day visit the website.