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John Smick's writings on SW Part 15 circa 2001

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Shortwave or HF Part 15 Stations (13,553 - 13,567 kHz)

Part 15 22 Meter HF (13.xx kHz) Transmitter Schematic Ideas

KEY:

(HIFER) = Acronym for "High Frequency Experimental Radio", basically the same thing as a LOWFER or MEDFER but at HF (see LF and MF Keys for more detailed explanations). "New" term coined by the LOWFER/MEDFER community to accommodate this "newly discovered" and rapidly-burgeoning field of experimentation.

No Suffix = As with the other listings these denote stations operating primarily or solely as broadcasters rather than as HIFERs, or those which include a significant broadcast-type program content in their operations.

HF Part 15 stations occupy a narrow slice of the 22 meter shortwave band in accordance with the provisions of 15.225, which specifies a field strength limit of 10,000 uV (10 mV) per meter at 30 meters from the antenna. In practice this works out to 1.8 mW transmitter output power into a 1/2 wave dipole, or 3 mW into an isotropic (0 dBi) radiator. While this power level may sound minuscule remember that by comparison, only a fraction (< 1%) of the power a 100 mW Part 15.219 AM transmitter feeds to its antenna is actually radiated by even the most 'efficient' 3 meter antenna; in fact, the amount radiated is roughly comparable what is permitted in this HF band, yet some impressive DX as well as local coverage has been achieved at MF.

On this HF band, unlike Part 15 mediumwave, there is no limitation on the size or type of antenna, feedline or ground nor on power output of the transmitter, except with respect to whichever combination of antenna and power chosen is required to reach the legal limit of field strength without exceeding it (and recalling that any gain effect even if incidental, such as might result from proximity to a reflecting suface or object, would cause an increase in field strength in the direction of maximum reflection which must be taken into account).

In any case while the power output allowed here is not tremendous, it is indeed enough to "work the world" based on Amateur Radio observations on similar frequencies and power levels, via the excellent ionospheric skip characteristics of the band. Local range depends of course on the receiver used, its antenna, the prevailing noise and interference levels, etc. but should be at least comparable to and probably significantly better than that of a mediumwave Part 15 station - unlike MF, at HF especially this high in frequency, there is essentially no significant groundwave component and thus a major source of path losses is removed - local propagation is via direct wave - and also the baseline atmospheric noise level is far lower here than at mediumwave.

The other main requirement under this Rule subpart is a frequency stability of +/- 0.01% under supply voltage variations of 85 to 115% of normal at 20 C (68 F) and under temperature variations of from -20 to + 50 C (+4 to +122 F). This might tend to scare off some potential builders but it is actually only 100 ppm, which is easily achievable with any reasonably decent oscillator and power supply circuit design and good quality crystals which are readily available from a supplier such as JAN or Bomar. Another possible design example: a CB crystal for 27.120 MHz and a simple 74HCTxxx series frequency divider would give 13.56 MHz and whatever the stability of the crystal originally was, it would be doubled (drift halved) using this scheme. It is also probable that this rule really applies to commercial manufacturers seeking Type Acceptance and for the homebrewer the FCC would tolerate a lesser degree of accuracy.

Canadian RSS-210 rules, Section 6.2.2 (e) permit operation in the same band but at slightly higher field strength, 15.5 mV/m at 30 m. Their frequency stability requirements are similar. Canada also has another license-free HF band not available in the USA; 6,765 - 6,795 kHz. Field strength and frequency limits are the same as those for 13,553 -13,567 kHz.

For AM broadcasting use, assuming a standard 5 kHz max. audio frequency (10 kHz occupied bandwidth), there really is only one frequency which can be used in such a narrow band: 13,560 kHz (this leaves a 2 kHz guard band on top and likewise, on the bottom of the band as well). It is recommended, in the interest of allowing as many as possible to use the band, that those considering broadcasting here either (a) reach an equitable time-sharing or scheduling agreement with other stations to avoid mutual interference, if using AM, or (b) operate SSB (Single Sideband), which is used by many full-power HF broadcasters around the world and occupies much less bandwidth than AM does.

Inasmuch as most shortwave receivers can "hear" SSB (have a BFO), this should not be a problem. Using less audio bandwidth on AM, when possible (for instance, 3.5 or 4 kHz instead of 5) can help reduce interference potential as well. Narrowband FM can also be used but unfortunately, many shortwave receivers likely to be owned by the public cannot "hear" this mode. NBFM might be better than AM though, due to less noise, for wireless studio-to-transmitter link (STL) use of this frequency range in feeding other Part 15 units on AM (MF) or FM bands (an idea originated by the author).

To the author's knowledge, no commercial manufacturer currently sells Certified transmitters for this band; or not, at least, for hobbyists/broadcasters - so it's "homebrew heaven" for those so inclined. One company, MaxNet, did offer lease of Certified NBFM transmitters for this range, at a HIGH cost, for STL/TTL use as part of a complete system of Part 15 FM's to be used along highways as sort of a commercial "TIS" setup.

Contrary to what some folks have been (erroneously) told by FCC personnel not intimately familiar with Part 15 Rules, this band is not strictly for ISM (industrial, scientific, and medical) use only; the author, in consulting with contacts in the FCC who write these Rules has learned that broadcasting here is indeed permissible (there are no written provisions to the contrary). However, United Parcel Service is planning to use this spectrum for specific applications and being a Part 15 operation as well, sharing the band and acceptance of occasional interference will necessarily be the order of the day (let's hope UPS sees it that way!) Also, those electronic anti-theft tags (RFID) found on clothes, CDs and just about everything else in stores today operate here too; you may want to avoid transmitting on this band too close to your local Mall!

The lack of experimental broadcast stations operating here is truly amazing, considering the relatively generous field strength allowance and great (world-wide!) propagation in this frequency range. This Part 15 band is available in the USA and Canada for use by people like us: hobbyists, low-power radio and broadcast enthusiasts, and experimenters; not many people in other countries are so lucky, and in the face of commercial pressures there increasingly is less and less spectrum available anywhere to the average RF experimenter - why not make good use of the band?

13,554.41 (HIFER) "MP", London, ON. Operated by Mitch Powell, VE3OT. On air: June 8, 2001. This station was one participant in the first-ever HIFER QSO on June 15, the other end being Jonathan Jesse's "JJ" (13,557.5 kHz) in Plymouth, MA. That distance is over 540 miles! Mode used was QRSS; a random number (3) chosen by Mitch, and callsigns were exchanged. Update 07/18/01: Both this station and "RY" (13,555.37, see below) were involved in a 12 wpm CW QSO with 100% copy according to Mitch.

13,555.3 (HIFER) "GL", Austin, TX. Operated by KI5GL. Mode QRSS, 3-sec. dots. Operator will QSY higher and can operate higher CW speeds upon request. Power is 1.5 mW into a 1/2 wave Cushcraft R5 vertical mounted 20' AGL. This station was heard in Maryland on Aug. 28 by W3NF; the distance is 1,295 miles.

13,555.36 (HIFER) "RY", Raymond, ME. On air July 15, 2001. Operated by: John Andrews, W1TAG of HIFER "TAG" 13,555.6 (see entry). Formerly "regular" QRSS mode but now (Sept. 2001) operating in DFCW (Differential-, or Dual-Frequency, CW) mode, 10-sec. dots and 5 Hz shift (dashes also 10-sec. duration but 5 Hz higher than dots). Heard by Mitch Powell, VE3OT in London, Ontario (545 mi.) on it's first day of operation! John had originally put this HIFER on-air with the intention of operating it on a temporary basis; but has decided to keep it operational for the time being since it is doing well and is widely-heard, perhaps more so than his other beacon "TAG"! This station was at the other end of the recent successful CW QSO at 12 wpm (also see 13,554.41 "MP"). According to a recent (Aug./Sept. 2001) post by John, the station will be taken off-air in Mid-October for the winter, until a better frequency-controlling scheme (more stable) can be designed as it is felt that the stability will suffer during the winter in the unheated environment where the beacon is located at present.

13,555.4 (HIFER) "LEK", Aitkin, MN. Operated by Lyle Koehler, K0LR of LOWFER "LEK" (186.7 kHz) reknown. On air: May 20, 2001. Ident cycle toggles between 12 wpm CW, 1 rep. ID and QRSS at 0.4 wpm, 1 rep. ID. 1.5 mW power, antenna is a ground-mounted 51' HyTower vertical. QSL. Amazingly, HIFER "LEK" has already (05/22/01) been copied in California and Massachusetts!

13,555.5 (HIFER) "NC", Stanfield, NC. Operated by Dexter McIntyre, W4DEX of MEDFER 510.5 and LOWFER 177.777 "NC" fame (see those listings as well). On air: May 9, 2001, making this the first "HIFER" beacon. Mode is QRSS, 3 sec. dot length. Power is 2 mW into a 1/4 wave vertical antenna. QSL. Since the recent 'discovery' of this site by a fellow Part 15 experimenter who posted a link to it on the LOWFER messageboard there has been a huge response vis a vis the possibility of experimental operations in this HF band, of which most MEDFER/LOWFER operators were not aware up to this point. Expect much more activity on this band shortly, now that they are! Update 05/20/01 A "band opening" has produced a slew of reception reports of the NC HF beacon from listeners in Connecticut, Massachusetts, Minnesota, California, Oklahoma, S. Florida and Ontario - and many of the reports indicate signal strengths sufficient for "armchair copy" and CW QSOs! Dex has prepared a special QSL card for the occasion. Update 05/25/01 Dex now also calls CQ at 5 wpm for possible CW QSOs at the top of the hour, every hour whenever possible.

13,555.6 (HIFER) "TAG", Holden, MA. Operated by: John Andrews, W1TAG. On air: July 4, 2001. DFCW mode; the carrier is shifted (in this case 5 Hz) to form "mark" or "space". The transmitter according to John, "...uses an Analog Devices AD9850 DDS chip, run by an 80C51 style microcontroller. It has an LCD display and a keypad, allowing menu selection of modes, IDs, speeds and frequency." See also John's other HIFER "RY", 13,555.36.

13,555.63 (HIFER) "WV", Richwood, WV. On-air 4:10pm Aug. 27, 2001. Operated by: Michael Tyler WA8YWO. Mode: CW, 4 wpm. ID is string of 6 "E"'s followed by 3 "WV"'s; 5-sec. silence between IDs. Hrs. opn: 24. Power is 1.5 mW, into a "sloper" dipole antenna.

13,556.51 (HIFER) "AWV", Ft. Lauderdale, FL. Operated by: Don Burns, K9AWV. On air: June 25, 2001. Ident. cycle is 0.3 wpm QRSS, 10-sec. silence. Uses 1/4-wave vertical antenna, Epson SG-8002 oscillator and K1EL keyer chip. Already (07/06/01) copied by Bill Ashlock of LOWFER/HIFER "WA" in Andover, MA - about 1,200 mi.

13,557.87 (HIFER) "PBJ", Apex, NC. On-air: Aug. 29, 7:30 pm. Operated by: Chris Waldrup, KD4PBJ. Mode is CW, 6 wpm. Hrs. opn: 24. The homebrew "Lyle Koehler Special" transmitter is enclosed in a weatherproof 5-gallon bucket container and powered by a gel-cell rechargeable lead-acid battery from a UPS, so is essentially an entirely independent system. Antenna is halfwave dipole oriented North/South fed with open wire transmission feeders. This new station was already heard in Massachusetts on Aug. 31 at midnight by John Andrews of HIFERs "TAG" and "RY". Thanks to Chris for kindly providing all the details on his operation!

13,557.9 (HIFER) "YK", Evansville, IN. Operated by Chris Lantaff, KE9YK. On air: June 6, 2001. QRSS mode. Uses an Epson SG-8002 oscillator on twice the frequency, with the output freq. divided by 2.

13,560 "Village Radio International", Montclair, NJ. A joint effort between the author (Amateur Radio W2MXW) and Village Radio Montclair (see their listings at 1620 and 1640 kHz). Not on air: target date Fall 2001. Format: Diverse programming - Big Band era, oldies, classic rock, and other musical genres; experimental/unsigned songwriters' workshop, talk, comedy, sports (live call-in show). Dups Village Radio pgmg. 90%. The author will be hosting additional talk and musical programming which will replace some of the Montclair-specific local material. Proposed hours opn: 2:00 pm - 12:00 am local time (1800 - 0400 UTC). AM mode. Power to be approx. 1.5 - 2 mW, into a 1/2 wave Inverted-V dipole antenna. QSL. At some future time, QRSS keying will be added during non-broadcast hours but at present VRI will leave the air when not broadcasting.

13,560 "FSR, Fallout Shelter Radio", Helena, AL. Not on air, target date Fall 2001. Station to be operated by Les Rayburn, N1LF in addition to HIFER "XM" (13,566.25 kHz - see parallel listing). This station however, will be a broadcast operation; the format will be 50's and 60's nuclear-era "Fallout Shelter" programs and audio clips from old "duck and cover" training films. Examples of this type programming can be found here. AM mode. Also, when not broadcasting, "FSR" will send CW messages, at QRSS (0.4 wpm) and normal (12 wpm) speeds, the slow message to be 3 reps of the call and the 12 wpm message being "DE FSR FSR FSR PART 15". QSL. Will operate on a time-sharing schedule with VillageRadio Montclair's operation. Your author is presently building a transmitter for Les, so operations will commence when that project is complete!

13,560 (HIFER) "TLTX", Sherman, TX. Operated by Tony Levstik who also operates LOWFER "TLTX" (184.283 kHz - see listing). Toggles between QRSS and 45 baud RTTY (Radio Teletype for those who didn't know :-) Power 2 mW into a 1/4 wave "longwire". Current operating schedule is weeknights and weekends.

13,560 (HIFER) "DG", Polk Co., IA. NEW. Not on air, planned for summer launch. Operated by: Dr. Tom Gruis, K0HTF. To be QRSS mode, 6-sec. dots.

13,562.7 (HIFER) "JJ", Plymouth, MA. Operated by Jonathan Jesse, W1JHJ. On air: June 5, 2001. QRSS mode, 3-sec. dot width. Hrs. opn: 24. This station was at one end of the historical first HIFER QSO of June 15, 2001, the other station being VE3OT's "MP" (13,554.41 kHz, see listing). Transmitter is an Epson SG-8002 programmable oscillator feeding a sloped vertical ("sloper") dipole antenna. According to a post by Lyle Koehler of LOWFER and HIFER "LEK", "JJ" is copiable in Minnesota even while "LEK" is transmitting only some 2.1 kHz away. Update: As of 07/23/01 "JJ" is temporarily off-air for repairs and will be silent for a "couple of weeks". Update: As of late Aug. 2001, "JJ" is back on, on it's new frequency of 13,562.7 kHz (formerly 13,557.5).

13,562.8 (HIFER) "WA", Andover, MA. Operated by William Ashlock of LOWFER "WA" 185.3 kHz - see listing. On air: May 28, 2001 at 8:00 pm EDT. QRSS, and experimenting with other digital modes. Uses a CB Ch. 14 crystal, freq. divided by 2. Bill sez: "...Will probably change over to the 13.555,X region of the band at a later date using one of the Epson programmable devices, but who knows maybe a Ch. 14/2 cult will form around my freq." We wish him luck! Uses 1/4 wave groundplane antenna. Update 05/29/01: On it's first full day of operation, "WA" has already been copied in Ontario! Update: on June 1, 2001, "WA" was heard in England, making this the first verified transoceanic Part 15 signal! "WA" was dubbed a "PondFER" by the receiving operator Jim Moritz, M0BMU of Hatfield, England, who received the signal on his computer running DL4YHF's SpectrumLab FFT software via a Racal RA1792 receiver and a "lash-up" dipole antenna. Hatfield is about 15 miles north of London. According to a post by Jim, "copy was not wonderful, but I saw several "WA"s between about 2230 and 0040 UTC last night. The signal was fading in and out, and was visible for a few minutes at a time. "...software was operating with a resolution of about 0.5Hz. The received frequency was 13,562.835 kHz +/- several Hz drift". The format was variable-rate QRSS according to Bill. Apparently, "WA" drifts a bit and has been variously logged at 13,562.69, and 13,562.75 kHz as well as the aforementioned frequency, so the figure specified in this listing's header is approximate. Those seeking the signal would do well to tune around a bit or use a wider RX bandwidth before "zooming in".

13,565 (HIFER) "ESA", San Jose, CA. Operated by: James Vander Maaten, WB6QZL of MEDFER "ESA" (1700 kHz). On air: July 9, 2001. 8 wpm CW, ident cycle is 4 reps "ESA" and DAID. Xtal controlled TX, 2 mW power and antenna is a 40-meter Inverted-V. Hours opn: 24. QRSS mode upon request.

13,566.25 (HIFER) "XM", Helena, AL. Not on air, target date June 2001. Beacon to be operated by Les Rayburn, N1LF who is well-known for his "XMGR" LF operation at 184.9 kHz and his excellent website about Part 15 experimental operations known as "The Noise Floor". Mode to be QRSS at 0.75 wpm. QSL.

Frequency Drift Clarification

SCWIS,

Thanks for posting this interesting article. I want to clarify something the author said. The article states:
Another possible design example: a CB crystal for 27.120 MHz and a simple 74HCTxxx series frequency divider would give 13.56 MHz and whatever the stability of the crystal originally was, it would be doubled (drift halved) using this scheme.

While it is true that the frequency drift will be reduced by a factor equaling the division ratio this will not change the drift as expressed as either percent or parts per million. Since the rules are stated using percent for drift, the original oscillator will need to meet the limit else the divided down signal will not.

This being said, the +/- .01% drift is not too hard to achieve. Anyone who is planning to build a transmitter can consider using an inexpensive crystal oven. I built a frequency standard for use here in my lab and once the oven is at temp. the frequency stays within 0.3 Hz for a 1.0 MHz crystal.

Neil

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