Amateur Television (ATV) Amateur High Definition Television by Jim Andrews, KH6HTV (pdf slides) ATV Handbook by Jim Andrews, KH6HTV I’ve collected as many of Jim’s newsletters as possible for your reading enjoyment. Will post shortly. MY ACTIVITIES: I was always interested in ATV, even from an non-licensed amateur for model rocketry. I discovered PC Electronics and bought a few items after I got my license. My interest faded due to the lack of other ATV operators in the area. But C4FM System Fusion - Yaesu FTM-400DR Quick Guide Manual Wires- X via DG-ID Wires-X Node Manual MY ACTIVITIES: I needed an alternate to DMR, so I chose Yaesu’s System Fusion. Also known as Compatible 4-level Frequency Modulation, CF4M is a digital voice and data communication mode used primarily in amateur radio. It uses digital tones to transmit crisp audio, GPS coordinates, and call signs across VHF/UHF frequencies. I love the color display and ease of use, especially for APRS. I own two UHF analog/fusion repeaters. DMR Connect Systems Incorporated CS800D PLUS Software/Firmware DMR (Digital Mobile Radio) DMARC BrandMeister Network: Dashboard MY ACTIVITIES: My first DMR radio was a CSI handheld CS700 for UHF. Due to the mountainous terrain, I upgraded to Vertex VXD-7200 mobile followed by a CS800 all of which are a pain in the next to program. The CS800D boasts ease of programming and more digital mode. I picked one up and time will tell. Unfortunately, the only DMR repeater I can hit from my home QTH is down. FT2/FT4/FT8 FT2: Features an ultra-fast 3.8-second transmit/receive cycle, allowing a complete QSO (contact) in about 11 seconds. It is optimized for contests and pile-ups where signals are strong. However, it is significantly less sensitive than FT8 and requires a modified, separate software program called Decodium rather than the official WSJT-X. FT4: Has a 7.5-second transmit/receive cycle. It was developed by the WSJT-X creators specifically for contesting. It offers a good balance of speed and sensitivity without needing extreme automation. FT8: The gold standard for weak-signal communication. It uses a 15-second transmit/receive cycle, which allows it to decode signals deep into the noise. FT8 Operating Guide - Weak Signal HF DXing for technophiles - by Gary Hinsen ZL2IFB MY ACTIVITIES: Running FT4/FT8 on a laptop connected to a Kenwood TS-480HX via a XGGComms Digimode-4-Kenwood from the car or picnic table made POTA so much fun! Using an Alpha antenna really helped on weak contacts, with my best FT8 contact to Indonesia. FX.25 FX.25 is a protocol extension to the AX.25 Link Layer Protocol. FX.25 provides a forward error correction (FEC) capability while maintaining legacy compatibility with non-FEC equipment. FX.25 was created by the Stensat Group in 2005, and was presented as a technical paper at the 2006 TAPR Digital Communications Conference in Tucson. Overview FX.25 is intended to complement the AX.25 protocol, not replace it. It provides an encapsulation mechanism that does not alter the AX.25 data or functionalities. An error correction capability is introduced at the bottom of Layer 2 in the OSI model. The AX.25 Link Layer Protocol is extensively used in amateur radio communications. The packets are validated by a 16-bit CRC, and are discarded if one or more errors are detected. In many cases, such as space-to- earth telemetry, the packets are broadcast unidirectionally. No back-channel may be available to request retransmission of errored elements. Consequently, AX.25 links are inherently intolerant of errors. The FX.25 protocol extension provides an error correction "wrapper" around the AX.25 packet, allowing for removal of errors at the receiving end. Data fields have been carefully chosen to allow reception of the AX.25 packet data within an FX.25 frame by a non-FEC decoder. (https://en.wikipedia.org/wiki/FX.25_Forwar d_Error_Correction) MY ACTIVITIES: Having a strong attraction to hardware TNCs, I decided to pick up a Kantronics KPC-XE USB 1MB TNC for two main reasons: 1MB mailbox and their latest digital mode addition: FX.25 which is great for low signal data. IL2P IL2P (Improved Layer 2 Protocol) is a data link layer protocol originally derived from layer 2 of the X.25 protocol suite and designed for use by amateur radio operators. It is used exclusively on amateur packet radio networks. IL2P establishes link layer connections, transferring data encapsulated in frames between nodes, and detecting errors introduced by the communications channel. The Improved Layer 2 Protocol (IL2P) was created by Nino Carrillo, KK4HEJ, based on AX.25 version 2.0 and implements Reed–Solomon forward error correction for greater accuracy and throughput than either AX.25 or FX.25. Specifically, in order to achieve greater stability on link speeds higher than 1200 baud. IL2P can be used with a variety of modulation methods including AFSK and GFSK. The direwolf software TNC contains the first open source implementation of the protocol. (https://en.wikipedia.org/wiki/Improved_La yer_2_Protocol) MY ACTIVITIES: I’m not fan of IL2P. It’s not compatible with AX.25 packet systems. Therefore, I’m leaving this one alone for the TARPN group. PACTOR PACTOR can be viewed as a combination of two earlier digital modes, packet radio and AMateur Teleprinting Over Radio (AMTOR). PACTOR provides improved throughput because its transmission speed adapts to the quality of the link and it uses Huffman compressed characters. PACTOR operates over half-duplex links and uses an Automatic Repeat reQuest (ARQ) protocol, acknowledging each individual data packet with a short Control Signal (CS). Some PACTOR implementations provide a Memory- ARQ feature to determine and store the relative strength of each received bit. Copies of corrupted frames stored this way are correlated with frames received later, to provide a coding gain for improved error correction. (https://www.arrl.org/pactor) MY ACTIVITIES: Still exploring PACTOR 1 through 4. POCSAG Paging While commercial paging has virtually disappeared, the amateur radio community has embraced this technology. Technical Data/Theory of Operation Digital Amateur POCSAG Paging Ham Radio Paging: Putting "POCSAG" on Packet W0XI POCSAG Paging Protocol - Raveon Hardware Alphapoc German manufacturer of pagers that cover the amateur frequencies. Kantronics has the 9612+ (out of production) and the newer 9612XE can encode/decode POCSAG. Wireless Devices Inc (Taiwan) These guys have tons of fun POSCAG toys! Their hardware including their pagers cover 2 meter and 440 amateur radio frequencies! NP-14 Series fully-programmable, single-board, POCSAG encoder with Hi power synthesized transmitter for the on- site paging system applications. POCSAG Encoder/Transmitter Module for IoT Application. Great item that will intercept your page and send it to your phone! Salcom 12-62-0000 POCSAG Paging Transmitter STI Engineering in Australia. WOW! Full VHF Band POCSAG Paging Trasmitters with and without Built-in Encoder that covers the 2 meter amateur radio band. The shame of it is they are grossly overpriced!! Software PE PE v3.10a by Clive Cooper, G8UKN and Pete Baston, GW0PJA is a DOS paging encoder for the PC. This is the software. I have the article on the interface by Robert B. Whitaker, but alas, I don’t have the schematics anymore. Check back often. This is on my list. In the mean time check out PDW below. PE-300 PDW Since 2003, Peter Hunt has made PDW the main (free!) Program to receive POCSAG and FLEX. PDW has users worldwide, from radio hobbyists to professional users. Peter has stopped developing the program after 10 years: he thinks it is 'finished'. Peter, thank you for all your efforts! PDW is now Open Source. The official site is HERE. These files are achieved locally and act as a mirror if/when the site goes down. PDW and RS-232 Port.doc PDW FSK to RS232 Schematics PDW2.14-full PDW2.2-full PDW3.10- full PDW3.12-full PDW3.2b01 MY ACTIVITIES: Currently, my Kantronics Node Stack incorporates a POCSAG Paing Server. Works nicely! Working on a paper on this. Robust Packet Robust PACKET, also known as HF-APRS, RPR, Winlink RMS, APRSlink, RPR-HF-APRS, and SCS Robust Packet, is an OFDM version of the amateur mode PACKET optimized for shortwave use. This mode was developed by Spezielle Communications Systeme GmbH & Co. KG (SCS), who developed the PACTOR protocol. Robust PACKET uses 500 Hz of bandwidth with 60 Hz spacing between carriers, and uses OFDM with 8 DBPSK or DQPSK carriers. On 200 bps mode, it uses BPSK. For 600 bps mode, DQPSK is used. For both modes, each subcarrier runs at a constant rate of 50 Bd. Like PACKET, Robust PACKET uses the AX-25 frame protocol for transmitting data. Compared to PACKET, Robust PACKET has better resistance against multipath propagation and fading. In addition, Robust PACKET takes less total bandwidth, with sidebands only extending out to 500 Hz, where with PACKET, the sidebands produced from the 300 Bd FSK extend as far as 730 Hz. (https://www.sigidwiki.com/wiki/Robust_PA CKET) MY ACTIVITIES: Purchased a couple of modems. Haven’t had time to implement this mode yet. RTTY RTTY (Radio TeleTYpe) is one of the oldest digital communication modes, dating back to World War II. Originally used by the military to send text messages via large mechanical teleprinters, it is now primarily used by amateur (ham) radio operators to send typed text over the airwaves Radioteletype (RTTY)[a] is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations connected by radio rather than a wired link. Radioteletype evolved from earlier landline teleprinter operations that began in the mid- 1800s.[1] The US Navy Department successfully tested printing telegraphy between an airplane and ground radio station in 1922. Later that year, the Radio Corporation of America (RCA) successfully tested printing telegraphy via their Chatham, Massachusetts, radio station to the RMS Majestic. Commercial RTTY systems were in active service between San Francisco and Honolulu as early as April 1932 and between San Francisco and New York City by 1934. The US military used radioteletype in the 1930s and expanded this usage during World War II. From the 1980s, teleprinters were replaced by personal computers (PCs) running software to emulate teleprinters. (https://en.wikipedia.org/wiki/Radioteletype ) RTTY (Also known as Baudot or ITA2) uses the Baudot 5-bit alphabet with FSK to send text messages over the shortwave. This mode is gradually dying out in favor of more robust modes like PSK31 in the amateur service. Uses the ITA-2 alphabet (Commonly known as Baudot, derived from the Murray code). Apart from occasional ham use, the only other known user is the Deutscher Wetterdienst (German Meteorological Service). Among amateur radio, the most common default mode of RTTY is 170 Hz with 45.45Bd. (https://www.sigidwiki.com/wiki/RTTY) Great articles I found on RTTY: Getting Started on RTTY Radio Teletype or RTTY by the Wireless Institute of Australia RTTY over Internet: test your sound card by receiving RTTY over the internet! MY ACTIVITIES: If it wasn’t for RTTY, I never would have gotten into digital modes. As a SWL, I would decode Associated Press transmissions using a PK-232. My bucket list is to set up a RTTY MSO someday. SSTV Slow-scan television (SSTV) is a method for picture transmission used by amateur radio operators to transmit and receive images. A technical term for SSTV is narrowband television. The most popular modes of SSTV are Robot, Scottie, and Martin. Commercial analog television signals require 6 to 8 MHz of bandwidth, because it transmits 25 or 30 picture frames per second (in the NTSC, PAL or SECAM color systems), but SSTV usually only takes up a maximum of 3 kHz of bandwidth. It is a much slower method of still picture transmission, usually taking from about eight seconds to a couple of minutes, depending on the mode used, to transmit one image frame. SSTV uses analog frequency modulation, in which every different value of brightness in the image gets a different audio frequency. In other words, the signal frequency shifts up to create brighter pixels and shifts down to create darker pixels. Color is achieved by sending the brightness of each color component (usually red, green and blue) separately. Sync is 1100 to 1300 Hz; channel information is 1500 to 2300 Hz. (https://www.sigidwiki.com/wiki/SSTV) MY ACTIVITIES: I have had brief, yet enjoyable experiences operating SSTV on 20 meters (14.230 Mhz USB) using Ham RAdio Deluxe several years ago. At the time, my transmitted pictures were slightly skewed due to frequency deviations in my clock. I’d like to get back into SSTV again. The software is the only thing holding me up. Report any broken links to ww2bsa@arrl.net