I had been a regular radio Dx'er in the old times and have used various radio receivers from valve to solid state and from home made to commercial ones. I gave up the hobby long ago and started to focus on music but the experiences still remain in memory
Here are some of my thoughts:
Any radio built properly and calibrated properly, can pick up regular radio stations on the MW (local), SW and FM bands. For long distance reception, you will have to use an external aerial (even for MW as the internal ferrite rod antenna wont suffice). FM long distance is very tricky as you will need to use a higher gain antenna (preferably yagi) and go higher with a mast and even better still with a low noise mast RF amplifier (called booster in India)
In the old days (well upto the early 1990s i would say), the major source of interference used to be fluorescent tubes and during festival times, people used fancy lights worked by starter-bulbs which caused irritating crackling sounds on radio and even on TV. I fondly remember the motor-boat sound on shortwave when an autorickshaw would pass by our street. One could get away with it to some extent by plugging the radio into a mains socket which was furthest from a fluorescent light and by using a good but dedicated earth connection.
And then, there was a band full of radio stations in those times, transmitting on shortwave and medium wave frequencies
I had used long-wire external aerials all along, made of galvanized wire of around 20 odd feet tied high with insulation, between 2 coconut trees usually, about 30 feet over ground level.
My last radio receiver was the great Siemens handheld 10band receiver, RK 621.
View attachment 60860
The situation now is rather different. With CFL and LED lightning dominating these days, the levels of interference has simply shot up. There are new appliances like induction cooktops and microwave ovens that contribute. Although FM is not so badly affected, MW and SW are severely impacted. To add to this, there is more RF around - cellular phone towers, wifi, etc
Most of the big world broadcast names have either discontinued their SW transmissions, reduced their coverage or reduced the length of their service daily. Srilanka used to host a number of relay stations for all the big names but all these have been shutting down one after another. Most of the radio stations have simply moved from SW to the internet.
I have not used any of the modern radios but i would assume that the focus is more on FM these days. Not sure about how many people listen to AM radio. A week ago, when waiting at my son's cricket coaching venue at around 6.30am, i tried manually tuning the MW band of my car's radio and was pleasantly surprised to hear Tirunelveli, Bangalore, Hyderabad and Chennai stations of AIR, apart from the local and powerful Trivandrum station. I did notice that by 7:30am, only Trivandrum could be received and the rest disappeared.
Regarding connecting aerials to the radio receiver, I have used 3 methods. During my childhood days, I used valve or germanium transistor radios with an external aerial connection, so i would just plug the aerial right in. Later on, when i moved to more sensitive radios, i discovered that connecting an external aerial to the telescopic aerial of the radio sounded nice mostly but also overloaded if the stations were powerful. A local HAM told me a little trick which involved taking a piece of hook-up wire, about a foot long and coiling it around the bottom segment of the telescopic antenna (which is not extended) ensuring that no physical connectivity happens. One end of this coil is to be connected to the external long-wire aerial. This is fantastic and gave me great results without upsetting the tuning calibration of my radios (caused by the constant overload with the direction connection). And then the same HAM gave me another idea - in those times, some radio cassette recorders would come with MW and SW radios, but with no antenna. For these what he said was, to simply take a metal plate, connect the external long-wire antenna to it and place it so as to rest across the back panel of the radio cassette. I recall using one of mom's old discarded stainless steel plates for the purpose with the aerial wire clipped on with a alligator clip. I also found out that connecting the aerial to a stainless steel vessel kept inverted and placing the radio over the steel vessel, also worked splendidly.
I also found out that if using power supplies (called battery eliminators in those times), one had to use proper filtering by adding filter caps and even better still, regulator circuitry. I used to do my experiments with filtering, by replacing the transformer output in my battery eliminator with electricity coming from a cycle dynamo (which was very noisy, electrically). I fondly recollect my brother peddling away on a bicycle on its stand while we fiddled around with combinations. For long distance reception, I always found batteries to be better as they offered 2 benefits, portability and of course, no direct contact with electrical interference sources. We could also carry our radio around in our locality, trying to ascertain the range of our small MW transmitter, which we made for fun and connected it to our long wire aerial. It was fun walking around in our locality, picking up the signal. Of course, as the batteries wore out, the radio would become less and less sensitive causing us to fiddle even more
Also an often forgotten or ignored aspect of radio reception is the time of the day and solar cycles. One cannot expect to receive MW long distance signals during the day and one has to switch between bands dropping to the lower frequency bands as the day turns to night, for SW listening. Read up some online info on Solar cycles (sun spots) and how they impact SW radio listening for more info.
Some good times and good memories
Additional info - shortwave bands and when best to listen:
Meter
Band | Frequency
(kHz) | Condition | Comments |
| 120 | 2300 – 2495 | Night | Mainly used ‘locally’ in tropical regions
Also used by government in North America |
| 90 | 3200 – 3400 | Night | Mainly used ‘locally’ in tropical regions
Used by various agencies of U.S. government |
| 80 | 3500 – 4000 | Night | Amateur (Ham radio) band
LSB (voice) and CW (Morse code) mode |
| 75 | 3900 – 4000 | Night | Mainly used in Eastern Hemisphere
Mainly Europe, Africa |
| 60 | 4750 – 5060 | Night | Mainly used ‘locally’ in tropical regions
Best reception during Fall and Winter |
| 49 | 5900 – 6200 | Night | Popular band for nighttime broadcasting
The best overall nighttime band for Int’l broadcasting |
| 41 | 7100 – 7350 | Night / Day | Int’l Broadcast, except North-South America
which is reserved for Amateur radio |
| 40 | 7000 – 7300 | Night / Day | Amateur (Ham radio) band
LSB (voice) and CW (Morse code) mode |
| 31 | 9400 – 9990 | Night / Day | Most Popular Int’l broadcasting band
Best mid-afternoon to mid-morning |
| 25 | 11600 – 12100 | Mostly Day | Popular Int’l band for daytime broadcasting
Good any time of day |
| 22 | 13570 – 13870 | Mostly Day | Int’l broadcasting
Not heavily used |
| 20 | 14000 – 14350 | Mostly Day | Amateur (Ham radio) band (Popular long-distance DX)
USB (voice) and CW (Morse code) mode |
| 19 | 15030 – 15800 | Mostly Day | Int’l broadcasting
The best overall daytime band for Int’l broadcasting |
| 17 | 18068 – 18168 | Day | Amateur (Ham radio) band
USB (voice) and CW (Morse code) mode |
| 16 | 17480 – 17900 | Day | Int’l broadcasting |
| 15 | 21000 – 21450 | Day | Amateur (Ham radio) band
USB (voice) and CW (Morse code) mode |
| 13 | 21450 – 21850 | Day | Int’l broadcasting
Seldom used |
| 12 | 24890 – 24990 | Day | Amateur (Ham radio) band
USB (voice) and CW (Morse code) mode, Best during sunspots |
| 11 | 25670 – 26100 | Day | Int’l broadcasting
Seldom used |
| 10 | 28000 – 29700 | Day | Amateur (Ham radio) band
USB (voice) and CW (Morse code) mode, Best during sunspots |
