My Top Band Adventure
Any mention of 160 Meters (often referred to as “Top Band”) usually conjures up images of extensive antennas strung up over large amounts of real estate. I always thought of 160 as a noisy, seldom-used ancient band left over from the early days of amateur radio, and never considered actually using it. I live in a condo, and antennas need to be stealthy and small; hardly compatible with Top Band activities!
I have a 14 foot vertical (made of nested aluminum tube) on the roof of our 5-story building, and have an Icom AH-730 automatic tuner at its base. The ground consists of the building’s sprinkler system standpipe, plus three 17 foot radials that are glued to the roof’s membrane. Cables run inside an air duct down to my shack in the suite below. I use an IC-7300 transceiver, which easily interfaces with the tuner, and I am able to get a decent VSWR on all bands from 6 to 160. The antenna works great for the higher bands, but I don’t get out that well on 80 meters because the radiation resistance of the electrically short vertical is quite small, and ground system losses dramatically reduce the efficiency. On 160, the overall antenna efficiency is probably not much more than 1 %, so my ERP is around 1 Watt – hardly what you need to operate in a contest!
Brian (VE7JKZ) is always encouraging me to enter into CW contests, and suggested that I enter the CQ 160 CW contest this weekend (Jan 24 and 25). I wasn’t expecting great things, but decided to give it a try. The contest started at 2 pm on Friday, but the band was absolutely devoid of signals at that time. Noise level (both natural and man-made) was high, but I managed to reduce it to a “dull roar” (S4-5) by using the 7300’s NR feature and narrowing the bandwidth to 150 Hz. Around 4:30 pm (just before the sun set) I started to hear signals. As darkness settled in, there were lots of signals from 1.80 to 1.85 MHz, and some of them were quite strong. I quickly worked the strongest ones, but then discovered that a lot of stations just couldn’t hear me! Even fairly strong stations would often not respond to my calls. I suspect that everyone has a local noise problem, and the criteria for being able to work a distant station is as much about their local noise level as it is the distance involved. I gamely kept working at it, and eventually made 25 contacts across most of continental US, and one each in Mexico and Hawaii. When it seemed like I had worked all the stations who could hear me, I shut down for the rest of the evening.
Saturday was nice and sunny, so I thought that I would try to improve the antenna situation. I managed to attach a 5 foot whip to the top of my vertical, which should have almost doubled the radiation resistance on 160. I thought that the improved antenna efficiency might increase my signal strength at a distant receiver by perhaps half an S-unit. Every bit helps! I got back on the air at around 5:30 pm on Saturday, and didn’t notice much of a difference. However, I did manage to log 13 more contacts before I packed it in for the day. Brian sent me an email to say that he had managed to log a JA station on 160, and I was impressed!
Sunday morning I woke up at 7:45 am and headed to the bathroom. The sun was just starting to appear to the East, so I assumed that 160 would be dead. I turned on the radio just to be sure, and things were pretty quiet except for a couple of West Coast stations that I had already worked. I noticed another good signal down at the bottom end of the band, and copied his call sign as JH4UYB. WOW! I gave him several calls, and eventually got him to respond with a question mark. The Japanese operator was very patient, and it took lots of repeats, but I eventually got him in the log! Apparently there were several Japanese stations being copied in BC for a one hour period around sunrise on Sunday morning, and I just happened to have the radio on then. The band soon completely faded away, and I shut down operations.
After just over 2.5 hours of operating on 160 this weekend, my final tally was only 40 QSO’s, but the experience gave me a new appreciation of what Top Band can offer. What a band!
I will have to come up with a better antenna for the next 160 contest! (Balloon? Kite?, Crane?)”
Cheers, and 73
Roger, VE7AP
Well done Roger! 160m is an interesting band that’s for sure. Growing up in the UK during the 1950s before 2m repeaters came along top band was the band for local communications, both fixed and mobile. The band was shared with coastal radio stations and it was not uncommon for CW operators to receive a call from a coast radio station asking them to QSY, hence the need for CW if you wanted an amateur radio licence. Power was limited to 10W maximum and a 10W AM transmitter was a common home built first transmitter. Receivers at the time were typically WW2 surplus; R1155s, HROs, CR100s and for the well heeled the AR88. Many US radios such as the HRO and AR88 ended up at the bottom of the Atlantic as convoys were sunk.
Amateurs operating mobile were surprised to find that operating at the top of a hill with a clear take off all around did not give the strong signal reports they expected when compared to operating on flat ground at lower heights. Ground conductivity of course, far better on flat ground with good earth compared to a rocky hill top.
In Canada there was also a power limit, 100W I seem to recall, and the band was shared with Loran A (Long Range Navigation). I was living in Ottawa at the time and the east coast Loran A wiped out the top part of the band. That was phased out and replaced by Loran C at 100kHz. At the same time the Omega world wide navigation system became operational using frequencies in the 12 – 14 kHz region. Omega has been phased out and GPS seems to have taken over. From the low kHz region of the spectrum to the gHz region, such has been the progress of radio navigation since WW2 and our ‘top band’ has been an integral part. of it.
73, Brian VE7JKZ