Sunday, August 22, 2021

FCC issue another experimental permit for the 40 MHz band in the USA (WL2XZQ)

On the 19th of August 2021, the FCC in the USA allocated the callsign WL2XZQ for experiments on the 40 MHz band from Houston in Texas. This was allocated to John, AE5X in the EM20 grid square.

This is I believe the second experimental permit for the 40 MHz band in the USA with the first one WL2XUP going to Lin, NI4Y near Atlanta, Georgia.

The permit for WL2XZQ allows for experiments in the frequency range of 40.660 to 40.700 MHz which is the 40 MHz ISM band (Industrial, Scientific, Medical).

The permit allows a maximum ERP of 100-watts and the license expires on the 1st of September 2023.

Propagation & Range - What to expect: The band is affected by several propagation modes. Let's have a look at them...

a) Tropo: It's likely that it will have a range of up to 200kms locally but it's unlikely that there will be many listening from that small area.

b) Sporadic-E: This will be main propagation mode from April to August every year and it WILL be heard all over most of the United States. The map above shows the likely range being in the range of 500kms to 2200kms. The most consistent signals should be in the 1200 to 1800km range.

In terms of double hop Sporadic-E, there may be a skip zones in the NE of the USA near New Hampshire and in the NW in the north of California and Oregon. The one issue for the western states may be interference from SNOTEL stations on the same band.

Looking further afield, there will also be times in June and July when there will be multi-hop Sporadic-E to Europe, a distance of about 6000-8000kms.

Trans-Equatorial Propagation (TEP): The experimental station is also well placed for tests to South America in May and November. While it is too far north for TEP, just one Sporadic-E hop is required to the south to open up the path to Argentina (LU), Uruguay (CX) and Brazil (PY).

F2 Propagation: The 40 MHz band will be certainly be impacted by the rising solar flux as we approach the peak of the next sunspot cycle. The 40 MHz band will open a lot earlier than say 50 MHz and it could prove to be a useful resource for European stations monitoring the trans-Atlantic path.

In Conclusion: This second experimental 40 MHz station is a very welcome development and it should mean that there is some amount of activity on the band in the Summer of 2022. This should raise awareness among the amateur radio community in the USA and perhaps more will apply for permits.

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