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FRB255 > SWL 29.11.22 12:02l 38 Lines 1515 Bytes #999 (0) @ WW
BID : 1620_FRB024
Read: GAST
Subj: comparison of 5 antennas for 2 MHz GMDSS-DSC
Path: DBO595<DBX320<DBX233<VB1BOX<NL3VKL<ENG040<FRB024
Sent: 221129/0926Z 1620@FRB024.#24.FGAQ.FRA.EU.WW BPQ6.0.23
I was curious about which antenna would be most effective for receiving
2 MHz transmissions, especially coastal stations from Europe. So I ran a
test with 5 of them in parallel last night, each into its own receiver
in Black Cat GMDSS (which supports up to 8 decoders at once). Here are
my results:
Antenna Good Bad ECC Coastal (total messages)
120 ft T2FD 241 187 284 61
250 ft V Beam 108 113 135 25
58 ft T2FD 23 15 18 0
500 ft Beverage 188 177 242 95
900 ft Sky Loop 130 167 271 52
The V Beam and Beverage are aimed towards Europe, the other antennas are
considered non-directional (probably a bad assumption).
Most but not all of the logged coastal stations were from Europe.
The 58 ft T2FD was expected to be a poor performer on 2 MHz. It is
interesting that the 120 ft T2FD picked up the most transmissions
overall, but T2FDs are renowned as good performing and low-noise
antennas. The Beverage picked up fewer total messages, but more coastal
stations, presumably due to being directional. I think I am most
surprised by the relatively poor performance of the V Beam. Due to it's
placement on my property, one leg is aimed directly at a neighboring
house, so it could be picking up RFI (I do notice a higher noise floor).
The Beverage by contrast is aimed towards a large wooded area with no
homes.
I should mention that version 1.0 of Black Cat GMDSS has finally been
released after about a year in beta :P
https://blackcatsystems.com/software/black_cat_gmdss_decoder.html
73
Chris
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