I grew up in West Chester Ohio less than a mile from VOA Bethany relay station and about a mile from 700 WLW broadcast tower in Mason Ohio. When VOA was broadcasting we had to turn everything off as it would overpower whatever signal was around, TV and radio. When newer electronics came out it was so nice. I am not sure what wattage VOA was running but if something had a speaker you could hear VOA and at times 700 WLW even if the power was off.
Radios not like they use to be
- Thread starter NDAR15MAN
- Start date
divingin
Gold $$ Contributor
If I remember my marine radio guidelines, a 6' antenna on-water has a LOS of about 5 miles.
A 300' antenna has a LOS of 21 miles, per an online HAM radio calculator.
An antenna would have to be 60,000' tall to get a 300 mile line of sight to something at ground level.
Nick Caprinolo
Gold $$ Contributor
Radios built today are designed to give very high fidelity. This will provide you with a clear and static free listening experience. In order to achieve this, there must be a means of filtering out distant stations operating on the same frequency. In essence, what is happening is that the strongest signal overwhelms the station that is hundreds of miles away.
In the past, frequency was controlled with the use of a VFO. This would pick up every station your antenna was capable of capturing. Consequently on a busy night, with good atmospheric conditions, you would hear more than one station on a given frequency. Most good receivers would have a secondary VFO, for fine tuning.
Most radios today use a digital, phased locked loop to tune a radio. This can be both good and bad for the public. The PLL is tuned by means of voltage change and is very selective. It won't tolerate two stations on the same frequency and only picks up the station that gives the strongest signal.
To further complicate things. Each frequency can be fine tuned by antenna length. Today's radios depend on an internal antenna or in the case of auto's, a one length fits all, which is most frequently found in the windshield or a very short external one. In the old days, you could adjust the length of your antenna buy manually extending it or in some cases with a built in motor. By doing this, you could differentiate or separate the signal you wanted to listen to. Of course you could always install an antenna tuner.
KM3H
In the past, frequency was controlled with the use of a VFO. This would pick up every station your antenna was capable of capturing. Consequently on a busy night, with good atmospheric conditions, you would hear more than one station on a given frequency. Most good receivers would have a secondary VFO, for fine tuning.
Most radios today use a digital, phased locked loop to tune a radio. This can be both good and bad for the public. The PLL is tuned by means of voltage change and is very selective. It won't tolerate two stations on the same frequency and only picks up the station that gives the strongest signal.
To further complicate things. Each frequency can be fine tuned by antenna length. Today's radios depend on an internal antenna or in the case of auto's, a one length fits all, which is most frequently found in the windshield or a very short external one. In the old days, you could adjust the length of your antenna buy manually extending it or in some cases with a built in motor. By doing this, you could differentiate or separate the signal you wanted to listen to. Of course you could always install an antenna tuner.
KM3H
KMart
Gold $$ Contributor
The line of sight meant that it was a straight 300 mile shot, not driving distance. The signal is unencumbered going over he Gulf of Mexico The signal will skip off water just like it skips off the ionosphere.
You would think, but in fact, that's not the case. I use to live about 1 mile line of sight of a transmitter tower located in the south San Francisco bay right next to an airport. It was/is part of Radio Free Europe and after midnight it would switch from local FM/AM station programming, power up and transmit english language lessons and news across the Pacific to Russia and China. I knew this because after midnight my stereo speakers would come to life (stereo was turned off) and I'd listen to their broadcast. In fact, I tried disconnecting the speakers from the stereo and they still played with no change in listening level, which was quite loud.
That's a good rule of thumb for marine frequencies, which I think are around 160MHz (VHF). For much lower frequencies like AM broadcast uses, you can get something called NVIS or "cloud warming", where the signal goes nearly straight up, hits the atmosphere, and comes down "only" a few hundred miles away. Hams call this local traffic, and it works well even when the sun spot activity is down.
pirate ammo
Guaranteed to take the wind out of their sails
Be docked in Abidjan,Ivory Coast, West Africa,turn SSB to 12 megs{megacycles} and talk to home office in New Orleans every night.
pirate ammo
Guaranteed to take the wind out of their sails
Now I know who done it.
The original question has been answered many times and well but saying the same thing in a different way: time was there were maxed out 50,000 watt clear channel after sundown stations. These days DXing demands equipment that's not FM home entertainment oriented. Mostly a matter of good optimized antennae. Most cars don't have the traditional whiskers but rather FM optimized embedded in the windshield and such. Myself I listen to world wide radio on the internet and by satellite. A big TV antenna and rotor such as were once common and are now rare will cheaply pull in a lot of stations.
rkittine
Gold $$ Contributor
Line of site, especially with VHF and UHF Radios doesn't take much power. I have worked the Challenger while in orbit more than one with a 5 watt hand help radio. Ground wave is something interesting when taking into consideration the curvature of the earth etc.
Yes, a Slinky Antenna is great. A standard metal Slinky is 32' of coil or about the right length for the 20 Meter Ham Band. Pulled out to about 8 feet or more on each side will make a passable antenna. Receiving or Transmitting, a resonant antenna regardless of length is the best. Long antennas though have great capture area.
You can transmit on a pair of Slinkies set up as a dipole. One on each side of a insulator. Coil on about a 6-8" center 6 turns of RG8 or RG8x Coax as a choke and wrap it with electrical tape. With that and a simple antenna tuner you can tune pretty much 10 meters through 80.
Bob
Yes, a Slinky Antenna is great. A standard metal Slinky is 32' of coil or about the right length for the 20 Meter Ham Band. Pulled out to about 8 feet or more on each side will make a passable antenna. Receiving or Transmitting, a resonant antenna regardless of length is the best. Long antennas though have great capture area.
You can transmit on a pair of Slinkies set up as a dipole. One on each side of a insulator. Coil on about a 6-8" center 6 turns of RG8 or RG8x Coax as a choke and wrap it with electrical tape. With that and a simple antenna tuner you can tune pretty much 10 meters through 80.
Bob
All this reminds me of my high school days in the hills of east TN, near Knoxville. I had a National NC88 multiband radio that an uncle gave me when it became surplus to him and 35-40 foot outdoor wire antenna strung up on the roof. At night and early in the morning, i would set it on the AM band (that one was built before FM was common, so just had AM and much short wave coverage) and listen to rock and roll on one of the outlaw stations on the Texas border that had their transmitters across the border in Mexico to get around the 50,000 watt transmitting power restriction on US AM radio stations. I remember this one was 150,000 watts. A number of years ago, ZZ Top did a song called "Antenna Head", I believe, about those high powered stations with transmitters in Mexico; it brought back pleasant memories of early rock and roll on those stations late at night.
I grew up in KCKS, delivered the Kansas City Times between 2-4AM. WLS out of Chicago, 500 miles away, was our go to station. At home I would listen to WLS, KAAY out of Little Rock, AR, and sometimes get a station out of New Orleans, all of them were AM. On a night drive to Colorado the summer of 1972 we picked up KAAY in western KS right before we got to the state line.
As @cem stated, there were stations that powered down or went off the air at night, and the clear channel stations that could power through. It was a pretty cool time.
As @cem stated, there were stations that powered down or went off the air at night, and the clear channel stations that could power through. It was a pretty cool time.
My wife (your ex) says you can have the poodle back. Tired of it crapping all over the carpets.
pirate ammo
Guaranteed to take the wind out of their sails
Time for a bar-b que.
Rick300
Gold $$ Contributor
KFRC was just about the only station we listened to "back in the day". My brother had a Craig floor mount 8 track FM in his Camaro that we would bring into the house at night. Hook it up to a battery charger and an old car antenna and we could pick up KZAP in Sacramento. I think there were only 2 or 3 FM stations back then. Good memories!
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