Antenna for weak AM station

There is a station near me, AM 1240. It's fairly weak, I'd love to be able to get it inside my trailer. Out in both vehicles it comes in OK. Talk radio, and some hosts I enjoy.
Been wondering if a mobile truck radio would work. Run an outdoor antenna. Mobile antenna from Wal Mart or something, from the auto department. Problem is, that the cowl mount antenna is for FM, right? I doubt I've got the skills to wire one in, too many wires on the back of a mobile. Any kind of radio come with outdoor antenna for AM? I guess I do have a ham set, an old Heathkit which is fitted for long wire antenna. C Crane is supposed to make good stuff, but a bit too high zoot for me.
Any other ideas?
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Christopher A. Young
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Weak AM reception, particularly near the high end of the AM band, from inside a trailer, with a marginal receiver, is not easy to improve without adding an external antenna, buying a good receiver, or both. I will assume that you have tried re-orienting the radio and cannot get adequate reception in any orientation.
There is a useful article you can read at:
http://www.mindspring.com/~loop_antenna/amloop4.htm
It illustrates the small advantage of buying a low cost Terk loop antenna, and the greater advantage of building a larger antenna from very low cost parts using the plans the author provides.
If your old Heathkit doesn't solve your problem, then either an outdoor long wire or a passive larger loop like the one described can be made for very low cost and coupled to your existing radio to make a significant difference. For quite a bit more money you can buy an amplified loop like the ones Crane sells, but they may not gain you much inside your metal trailer.
An automotive radio with the right antenna can be a very good solution. They work well because automotive radios in general are designed for good AM reception (not very often found in radios being made and sold today otherwise). Also, if you installed an outdoor antenna and played with the orientation, you are very likely to solve your problem (given that your vehicles both already can hear this station using an essentially identical combination of a good sensitive automotive receiver and an antenna placed outdoors). You would need a car radio, 12 volt power supply, and a typical vertical whip. You could also make and attach a long wire which would also work.
Your least expensive solution is to wire an external long wire outdoors, bring the wire into your trailer, and wrap it a few times around your radio to inductively couple the signal. If you are comfortable working inside the radio, open it and locate the AM antenna, usually a small ferrite rod wrapped with many turns of Litz wire, and couple your antenna to the terminal of the internal radio antenna through a small bypass capacitor.
An older stereo receiver with AM and FM terminals for antenna connection can maybe be picked up on eBay, craigslist, or locally for ten or 15 bucks, and is another possible solution with a directional ferrite loop antenna which can be oriented carefully or a long wire which can be run outside.
One final thought......... many radio stations now have an Internet stream, and you may possibly avoid needing an RF / antenna solution altogether. You might Google for the call letters or call the station to see if they offer this service.
Hope this offers some ideas,
Smarty
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On Nov 28, 2:37 am, "Stormin Mormon"

Auto/truck radios have to be fairly sensitive to weak signals because of the relatively short length of the antenna on the AM band **. The length of the antenna is much less of a problem on the shorter FM wavelengths.
It should help considerably to add something outside a metal trailer such as a length of wire or a standard auto antenna. However most (at least older radios) have an antenna trimmer capacitor (or similar) that 'must' adjusted for each set up. It usually makes a major difference to how strongly the signals are received.
My experience based on living in and repairing radios and TVs while living in a trailer for several years some 50 years ago! If the added wire is too long it may defeat the necessary adjustment for signal strength; so a suggestion would be to throw no more than 8 to 10 feet outside, tie it something to keep it clear of the metal siding and adjust the antenna trimmer for best signal on that, at 1240 kilohertz.
The 1240 kilohertz being, probably your most desired signal?
** The AM broadcast band is from around 500 kilohertz to approx. 1600 kilohertz. Those frequencies are the equivalent of radio wavelengths of 600 metres (that's roughly 1900 feet) to 190 metres (that's roughly 600 feet), so the length of a standard auto antenna is very short in comparison to those. The AM broadcast band frequencies are therefore below any 'Short Wave Band'. And 1240 is sort of up past the middle of the AM broadcast band.
A frequency of 1240 kilohertz = 242 metres or about 800 feet.
Accordingly; do not confuse short wave equipment, such as that produced by Heathkit for specific very narrow radio amateur frequency bands (typically at 80 metres, 40 metres, 20 metres etc.) as being suitable for either AM broadcast or the FM broadcast bands.
The FM band is (In North America) from 88 megahertz to 108 megahertz. These equate to wavelengths of 3.4 metre (roughly 11 feet) to about 2.8 metres (roughly 9 feet). So again these are shorter than most 'Short wave bands'.
An additional comment, from experience, is that many small bedside radios etc. have a tuned loop antenna inside a plastic or wooden case. While these do a good job in most conventional buildings they do not work well inside any metal shielded unit, such as a trailer. We also found this out in our first house which had aluminum foil insulation in the walls. Metal siding used on some homes could also cause shielding.
Hope this helps. Just experiment a bit and keep it simple.
I recall many, many years ago my father needed to ground his radio. He ran a wire out through a window and soldered it to an empty sardine can, which he buried in the flower bed below the window. Simple, cheap and effective even if the can rusted out a few years later!
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On Fri, 28 Nov 2008 00:37:42 -0500, "Stormin Mormon"

I found that experimentation works well. Attach a wire to the radio and move it in differenct directions. Try a short and a long wire. More and more radio stations are streaming online--with that the quality surpasses any antenna.
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A Terk loop antenna placed near the radio works wonders. It's an impedance matching device, and brings up the apparent sensitivity of AM radios that have an internal loopstick (the usual kind).
It helps most with cheap radios. Top-notch radios for distant AM reception already are impedance-matched pretty well and so the additional loop doesn't add anything.
They also help most in the daylight hours. At night your problem is too many stations, not stations that are too weak, and you get no help from the loop with that.
1240 in particular is one of the frequencies that gets wiped out by a thousand other 1240 signals at night.
Picking one loop source at random from Google http://yhst-38616620066226.stores.yahoo.net/dbadvantage.html
You can look yourself for a better price.
The loop really is pretty amazing in the daytime, and maybe worth getting for that reason alone.
--
snipped-for-privacy@mindspring.com

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The new walmart clock radios with am/fm are dirt cheap and produce fantastic AM reception at 1240.
To make them even better at receiving AM, just connect any non-shielded outdoor TV antenna lead to the back of the radio with duct tape. There doesn't need to be any electrical connection.
On Fri, 28 Nov 2008 00:37:42 -0500, "Stormin Mormon"

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Set the radio and your landline phone near each other. An outside phone line can pick up AM radio signals and couple the signal to a nearby radio. Useless if you don't have a phone line, or if it has DSL on it.
Also, local stations can have day and night power and pattern restrictions after sunset. Check with the station to see if they have a day and/or night pattern and what the pattern might be. If you have been by the station antenna, more than a single tower would indicate they do change patterns to protect another station's coverage from interference. AM towers are usually 200ft and have guy wires with several "randomly" spaced insulators in each leg.
If you are in the "null" of a common three tower in a row pattern, it's very possible you will never get a usable signal at night when the station feeds an out-of-phase signal to the two end towers at night. During the daytime, the two end towers have no signal applied and the center tower will radiate a full 360 degrees, at night the radiation will be a figure-eight with the null broadside to the three towers. There is a local station with six towers that at night has a single flare shaped finger that only covers the city.
Did you check if the talk show is syndicated? You might have better reception from another station, maybe a "clear channel" station.
Happy listening!
btw- also google "antenna tuner", a simple variable capacitor and a coil circuit that can make a big difference in reception. It's related to the effect of adjusting the trimer cap on the back of an automotive radio mentioned in a previous post.
-- larry/dallas
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Stormin Mormon wrote:

Quite a few stations stream content.
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I don't have a boat.
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Christopher A. Young
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Build a tower out of beer cans.
[Don't take it personal. I did my share of trailer time too.]
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Best idea I've heard, yet.
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