The antenna is optimized for 162-MHz for AIS reception, but this works very well for NOAA Weather Radio reception, too. The driven element of the Yagi is a loop. This tends to reduce electrical noise getting into the antenna by eliminating the high impedance of the ends of a conventional Yagi element. Away from the resonant frequency, the loop element works more like a dead short across the antenna transmission line than as an antenna.
The gain of the antenna is probably in the region of 5-deciBel compared to a dipole. In VHF Marine Band antenna terminology 9-deciBel gain.
To preserve signals, the transmission line from antenna to receiver is 55-feet of Times Microwave LMR-240UF cable. The estimated loss in the transmission line at 150-Mhz is only 0.5-dB. This transmission line cost about $100 with the necessary connector costs and shipping cost from the vendor.
The VHF Marine Band Yagi antenna joins two other antennas in the attic: a long UHF Yagi television broadcast band antenna and a dipole antenna for the FM Broadcast band. Without those two antennas television and FM broadcast reception would be impossible at my location.
The receiver is an older Standard-Horizon GX1500 VHF Marine Band radio, now relegated to a monitoring radio for VHF Marine Band and NOAA Weather Radio reception.
Here is a summary of NOAA Weather Radio stations received with sufficient signal strength to clearly copy their forecast and their station identification; the list is in order of the channel numbers on my particular receiver, the frequency in MHz, the FCC callsign, the weather office producing the broadcast information, and the transmitter location:
- WX-1 162.550 KIG74 Sault Ste. Marine; Tx at Dafters
- WX-2 162.400 KIH22 Gaylord; Tx at Traverse City
- WX-3 162.475 WNG572 Petoskey; Tx at Good Hart
- WX-4 162.425 WZ2515 Marquette; Tx at Grand Marais
- WX-5 162.400 WNG576 Marquette; Tx at Newberry
- WX-6 162.500 WWF70 Gaylord; Tx at Waters
- WX-7 162.525 WNG701 Detroit; Tx at Bad Axe
The time of day and weather conditions affect radio propagation. Listening early in the morning after a calm night with little wind seems to be conducive to enhanced propagation, likely due to temperature stratification in the atmosphere affecting refraction of VHF radio signals. About two hours after sunrise the weaker signals on the longer paths fade into the noise.
On WX-1 162.550 KIG74 in Sault Ste. Marine is generally good copy with some enhanced propagation. There is a lot of water in the 104-mile path from the transmitter at Dafters to Northport.
Depending on propagation at any particular time, reception on WX-1 at 162.550-MHz of KIG83 in Alpena may be possible; I heard a weak signal from them one afternoon.
Surprisingly, WX-2 at 162.400 KIH22 from Traverse City is very weak, which I attribute to the heading for this path being about 90-degrees off the main lobe of the antenna; there must be a deep null in the antenna pattern at that particular azimuth. The propagation prediction for KIH22 shows good coverage at my location.
The strongest signal is WX-3 WNG572 transmitting from Good Hart, almost an all-water 41.8-miles path to my location; it is solid and noise-free copy around the clock. Ironically, the modulation on this station is marred by significant hum on the audio.
On WX-4 162.425-MHz W2515 from Grand Marais in the Upper Peninsula requires some enhanced propagation to be heard.
On WX-5 162.400 WNG576 from Newberry in the Upper Peninsula also requires enhanced propagation to be heard.
On WX-6 162.500 WWF70 Gaylord with transmitter at Waters is generally solid copy at all times although with some noise.
On WX-7 162.525 WNG701 at Bad Axe was a complete surprise to hear on a very calm early morning. The path is a very long, all-terrain path from Bad Axe to Northport, and this reception will likely only occur sporadically.
With seven stations on the first seven channels of the weather band, this is very good reception; the usefulness of NOAA Weather Radio Broadcast stations as a means of verifying the general working of the antenna, the transmission line, and the receiver is also demonstrated by this "full house" of seven stations being heard.
I also discovered that in order to reduce local radio noise and allow reception of marginal stations, I had to unplug the charging cord from a nearby MacBook Pro 15-inch laptop. At first I thought the computer was generating the noise interference, but with some further investigation the noise was being created by the charging cord. If I had been monitoring with the laptop powered on and being charged, I would have not noticed two or three of the weaker signals. An electrically-quiet receiving location free of locally generated radio frequency noise is essential for weak signal reception.
Nothing was heard on the channels WX-8, WX-9, and WX-10. Weather Band channels, WX-8 and WX-9, are usually used in Canada.
WX-8 is 161.650-MHz. In the legacy VHF Marine Band channel plan, this was the shore station transmit frequency for semi-duplex communication to ship-to-shore on Channel 21. Channel 21 was a split channel, with ship stations transmitting on 21-A at 157.050-MHz and shore stations transmitting on 21-B at 161.650-MHz. This allowed semi-duplex operation, with the shore station operating at full duplex, that is, able to receive and transmitting simultaneously without interference, and the ship station operating at simplex, that is, only able to transmit or receive, one at a time. The old ship channel (21A) is redesignated Channel 1021 at 157.050-MHz with use in the USA reserved for the U.S. Coast Guard. The old shore station channel 161.650-MHz(21B) is now for Continuous Marine Information Broadcasts. These broadcasts are common in Canadian waters, in include weather information, sometimes in MAFOR code, along with Notice to Mariner readings.
In a similar manner the 161.775-MHz frequency was once part of Channel 83. Ships transmitted on 157.175-MHz (83A) and shore stations transmitted on 161.775 (83B). The 157.175-MHz frequency is now simplex channel 1083, with use in the USA reserved for the U.S. Coast Guard. The old shore station channel 161.775-MHz (83B) is now allocated for Continuous Marine Information Broadcasts.
A tenth weather channel is at allocated at 162.275-MHz for NOAA Weather Radio, but I don't recall ever hearing a station on that channel.
As far as I know there is no "official" assignment of channel numbers to these weather broadcast channels, but many VHF Marine Band radios follow the numbering convention mentioned above. The WIKIPEDIA.COM article on "weather radio" goes into more history and details: see
https://en.wikipedia.org/wiki/Weather_radio
ASIDE: we used to spend most of our time boating in Canadian waters, and we enjoyed listening to the Continuous Marine Information Broadcasts, which in those days were often read by actual human beings instead of automated voices. The Canadian stations in Ontario usually had a radio operator with a Scottish accent, which added to the notion of being in a foreign country. We got all our weather data from those broadcasts. This was long before the internet and getting an internet WiFi connection in every marina.
Our favorite station was Wiarton Coast Guard Radio, which broadcast on several frequencies simultaneously. We were always in range of their signal throughout the North Channel and Georgian Bay of Lake Huron.