Back in 1982-1984 when The Crystal Ship was first on the air, 7425 kHz was "THE pirate frequency". Years later it became 7415. Both at some point were taken over by powerhouse international broadcasters, making them useless for pirates, so the popular pirate frequencies kept changing.
I guess it must have been sometime in the 90s when 6955 kHz became a consensus frequency. I would guess this range below 7 mHz became attractive due to the lack of broadcast activity there at that time (I wasn't active or connected when this happened, just surmising). Now 6955 often has utility transmissions, and 6925 is usually clearer and the most active frequency, but both are still used somewhat.
My station, The Crystal Ship (TCS for short), has probably been the most "frequency-prolific" of the past few years. We've purposely stayed away from the pirate-pileups on 6925, using other unused frequencies below 40 meters such as 6875, 6855, 6900 and most recently 6700 kHz. Generally, when we change frequencies, its due to being crowded out by high-power stations moving on or near-channel, or being too close to MARS/military communications.
TCS as well as MAC Shortwave have utilized frequencies above and below 80 meters, especially during the winter, when 6.9 mHz "goes long" very early in the evening and would skip over most of our regional audience--most of whom reside in the northeastern quarter of the US. This allows more people to successfully tune in, although the noise is worse down in that range. (3200, 3275, 3430, 4070 kHz).
I decided to vacate 3275 this past winter, due to 'too close' proximity to MARS nets, whose operators started to comment on the station...
Last summer and currently, we have been using 5385 kHz as a parallel frequency to whatever 6-7 mHz frequency we run, for the sake of closer-range listeners who would be skipped over by the higher frequency. It's somewhat less noisy than 3430 would be, and in the summer doesn't skip over nearby listeners too early.
The 7300-7500 range is mostly unusable from late afternoon on, due to the number of international broadcasters who now transmit in that range. However, from about 7575 kHz on up is mostly clear. TCS has started experimenting with 7575 kHz due to the days being at their longest. Although the "skip zone" is somewhat larger than for instance 6700 kHz, the noise seems to be surprisingly lower up there. During the last such broadcast, I received an Emailed report from California by the first listener there able to receive it in AM mode (the only other report ever received from there had to use SSB to discern the transmission). After four years around 6.8 mHz, I have to credit the report to a lower noise level on 7575. Back to back recordings of the station made from Florida, on 7575 and on 6700, showed a beautifully quiet 7575 signal-to-noise ratio, whereas the one on 6700 was "kind of a mess". I was quite shocked at the difference.
I expect we'll keep playing with that through the summer; come late fall, that frequency range would be going long earlier than 6 mHz, so we probably would not be using it then... although hours after dark, it might be quite good for the western US...
Other pirates have experimented with transmissions up around 13.9 mHz; we've done some around 12.5 mHz (since one particular antenna was resonant there). The higher frequencies would make for a much lower noise situation, but the problem is that the skip-zone is much too large for a pirate intending a domestic audience. Depending on the time of day, the transmission could be skipping over the first 700 or 1000 miles around the station, leaving most listeners without a chance of receiving it. That range might be good as a parallel frequency meant for your DX listeners alone, but as a stand-alone frequency most potential listeners may not be able to hear it, unless you happened to be located far from the bulk of them. Most of the transmissions up around 14 mHz have generated few reporters, especially relative to everything going around 6925.
Most pirates tend to stick close to either side of the amateur radio bands, especially if using ham transmitters, since that's where the equipment works best (or at all).... and we stay OUT of their bands, in the US at least.
John Poet
The Crystal Ship
Topic: Other Frequencies (Read 2187 times)