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  #76  
Old 08-15-2007, 08:55 PM
NowhereMan 1966's Avatar
NowhereMan 1966 NowhereMan 1966 is offline
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Quote:
Originally Posted by Jeffhs View Post
When I lived in suburban Cleveland, 18-20 miles east of the city, I had excellent AM reception, but one station in particular (50kW then-WGAR-AM 1220) would come in louder than normal whenever I would pass by a pole that supported the school speed-limit sign (I lived near an elementary school at the time). I've always wondered why. The only explanation I can come up with that makes any sense to me is that I may have been directly in line with the station's daytime signal pattern when I walked near that pole. I did not notice this, however, with the other 50kW station in Cleveland (then-WKYC-WWWE-AM, now WTAM 1100) or with any of the smaller stations (Cleveland has a handful of 5kW stations, one 1kW station, and a bunch of stations 1kW or less in the suburbs).

I was not aware that KDKA-AM had changed antennas in the mid-'90s. What happened? Did the old tower come down in a storm? If the original antenna tower had been up since 1937 (57 years), it may have been due or even overdue for a change.

KDKA-AM, like most 50kW AM stations these days, must share its frequency (1020 kHz) with smaller stations, in accordance with new FCC rules that did away with clear-channel AMs (and allowed former daytime-only stations to operate full-time under certain conditions) in the mid-1980s. It may be, since KDKA is no longer a "clear channel" station, that its signal isn't as strong during the day as it once was; at night, the station may have to reduce its power output and/or change its signal pattern so the latter is directional (concentrating the signal in one direction). The station may be running directional during daytime as well.

How far are you from KDKA's transmitter? If you are some distance away, the signal could be weak to begin with; any interference could chop up or even mask it entirely.

Interference to AM radio is a real problem these days, even more so than it was, say, 25 years ago. Today we have cellular telephone towers, pager towers, police radio, etc. all operating at the same time. If you are near any of those towers, your AM radio reception could and likely will be riddled with noises; the noise you report on KDKA's signal that sounds like diathermy could be interference from a nearby cellular or pager transmitter.

Noise levels in apartment buildings are often high as well. I live on the first floor of a 2-story building; my AM reception is often marred by noise, especially on my Zenith C-845. I oftentimes cannot hear a 50kW sports station on 850 or a talk station on 1100 because of the high noise levels. The problem is especially bad when listening to AM on my C845 because the radio has a 6BJ6 RF amplifier that works for both bands, AM and FM; the tube winds up amplifying everything the antenna picks up, including the signals. The irony is, IMHO, that there is no noise whatsoever on FM on any of my vintage radios. Being a ham radio operator, I ought to know why: because AM signals are much more prone to interference from sparking brushes in motors, microwave ovens, etc. than are FM signals. FM is almost completely immune to noise interference, which may be yet another reason why hit music left AM and migrated to FM. It was probably the best thing that ever happened to vintage and classic rock, not to mention classical music.

BTW, I was very sorry to hear (have read in one of your posts) that another of your cats has passed away. I know the feeling, as I had to have my first white cat, Shawn, put to sleep in 2002 (he was in the last stages of severe liver damage at the time, according to the vet). My second cat, Jonah, also pure white and looking exactly like Shawn, however, is doing very well. He's sleeping on the floor about three feet behind me as I write this.

Seventeen years is a very long life for a cat. I'm sure both Pansy and Boo have left you with tons of nice memories. I know my Shawn did, and Jonah will too, when the day comes (heaven forbid) that he either dies on his own or I have to have him put to sleep.

Just remember all the good times you had with Boo and Pansy, and you'll be just fine. If I remember correctly, you still have several other cats around, so you'll have their company for at least a few more years.
Another weird thing I noticed when I listened to KDKA-AM is sometimes it would go "out of phase" and have muffled sound, but not recently. I guess I live 15 or 20 miles away from the transmitter and the signal is generally omni-directional and that is both day and night according to www.radio-locator.com. I remember when they switched the tower, for the longest time, their signal cut in and out when we had winter wind storms too. I've picked up KDKA in Florida and Texas although the latter, I had to orient the radio to null out another 1020 station out of Roswell, New Mexico.

I'm surprised how KDKA lost a lot to the first FM talker here in Pittsburgh. WPGB is on 104.7 Mc here in Pittsburgh and they first took Rush Limbaugh away from KDKA and then the Pittsburgh Pirate games. Except for a couple of years in the 1950's, KDKA always carried the Pirates since 1921.

Can't get 1100 too well, you must be prone to a lot of RF interference. I know the feeling when I'm at work, AM is useless.

As to my cats, yeah, it is tough losing them but I'm glad we recently got a new kitten so he is a help. That reminds me, got to give Corky her IV fluids tonight to help her kidneys. Thanks for the condolences.

Chuck
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  #77  
Old 08-15-2007, 08:59 PM
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NowhereMan 1966 NowhereMan 1966 is offline
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Quote:
Originally Posted by radio63 View Post
So sorry to hear about the loss of your kitties. I have lost pets before and it is always a traumatic process. I have two cats which are a lot of company. That would be great to start a pets thread. I bet it would generate a lot of interest.

Gilbert

Thanks. Yeah, it's hard, plus my 18 year old cat, Corky, she is diabetic and needs fluids to help her kidneys but I'm glad to do it to keep her around to have a good life. She is a great comfort to me, she comforted me when I had a serious problem at college in 1989 when she was a kitten, in 1997 when Grandma passed away and just now when Boo passed away. I plan on starting a pets thread this weekend in the general forum. She does like to eat a lot though, it's slow putting weight on her because of her age mostly plus her condition but beyond being a little underweight, she is fine.
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  #78  
Old 10-20-2007, 11:13 AM
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Paul C Paul C is offline
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Small portables have a "ferrite coil" antenna, which works well.

I used to be quite frustrated about driving around, listening to something on AM, arriving home, and having to sit in the car to hear the rest of the show. Wife - "Honey, what are you doing sitting out here in the driveway? Are you OK?" Yeah, but I could not hear the AM station on my home stereo tuner that I could easily hear on the car radio.

OK, some guys will say, "You need a 'longwire' antenna." I've tried them, they just don't work for AM until you get at least 150' or so of wire stretched out. They just aren't practical.

This is from MTM Scientific, and is a nice version of the "sports fan's loop".



It is a tuned loop which gives more gain, is fine tuned with a common tuning capacitor. You can buy the plans, but there are any number of similar loops plans you can find online.

These tunable loops can provide an even stronger signal.

http://www.mtmscientific.com/loop.html

http://www.mindspring.com/~loop_antenna/

http://www.angelfire.com/mb/amandx/loop.html

http://www.midnightscience.com/catalog5.html

A tuned loop construction and operation:

http://youtube.com/watch?v=QpGXECoY6zg Tuned loop Part 1

http://youtube.com/watch?v=6HRZcTL15ZA Tuned loop Part 2

You can add just a high impedance earplug/earphone and 1N34a germanium diode to a tuned loop and you have, voila!, a crystal radio!

So, where do you put these antennas? One guy mentioned that he built his loop antenna on the inside of a closet door, and simply swings the door open to closed to aim the antenna. Loops have a figure 8 reception pattern, so you only need 90 degrees of rotation.

Anyway, having a good antenna attached to your tuner will make all the difference in your AM listening.
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  #79  
Old 10-20-2007, 12:09 PM
goraman goraman is offline
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I'm about to date my self but in the sacramento area we had 3 rock stations KROY,KROI one was AM the other FM I can't remeber which but I belive KROYwas AM and on FM we had good ol KZAP.At night you could listen to Wolf Man Jack,I miss those days they where very simple times.Everyone was an American 1st and no one would have thought a political party would try to stop free speach on AM radio because they didn't agree with it.And now we talk so much about tolarence but fail in everway to understand and practice it .You could belive the main stream news then to some degree .And when someone moved into your neiborhood your father would take over a six pac of beer and introduce him self to the man of the house,people helped each other tinker on projects,the family car or just pulling a stump was a neiborhood event My DaDs old 61 ford had a compound 4speed 411 gears in a possitraction rear end with a little 292and this little white and yellow truck was then the neiborhood stump puller as a kid I remeber a chain came loose and when the truck lerched forward a 4 foot section flew over the cab and landed in a feild across the street over 100 yards away.my dad came back with it and the hooks had sherd off and he said if it has gone through the rear window into the cab I would have lost my head! sorry to dygress but I just remember a time when people stopped by just to hang out in our garage and see what my dad was working on as back then men alwasys where building something or fixing somthing them selves the radio was always on and no one really gave a crap if you where republican or a democrat because we where all to buisy being americans,neibors and freinds.
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