Antenna booster for AM reception

Back in the good old dayz of tubes, some of the radios had a built-in antenna booster to be used when needed. There are a few ways to do this; make a "large" loop of many turns of wire (usually a flat loop geometrically wound like a spiral and large unused center). One side goes to ground of radio signal input. Usually a low-Z tap from the loop connects to the radio antenna, sometimes witha small trimmer cap (5pF-25pF). Some variations use a tuning cap across the loop. Orient the loop for best reception. Other variants use a long outdoor antenna coupled to the loop with the tuning cap.

What city & state are you in? What is the AM Station call sign you are trying to receive?

Is this by any chance an auto radio? If so, make sure the antenna cable is connected and the antenna properly installed (grounded, etc.). Also, some radios have an antenna trimmer that can be adjusted to improve the match between the radio and whip antenna.

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1 - Yes they can work very well 2 - Yes, See It is pretty expensive, but is available built and tested. I'm sure there are others. I built my own similar to this one and it works very well. 3 - Advanced/Simple depends on your perspective, but if you can solder & read you can probably buid a kit.

Mike

"In view of such harmony in the cosmos which I, with my limited human mind, am able to recognize, there are yet people who say there is no God. But what really makes me angry is that they quote me for the support of such views." Albert Einstein (theoretical Physicist)

...

Build....

Or Buy...

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I was looking at some that are ready built, but I guess they just boost the level of sound, not the signal. So I will have to re- request what I am looking for - I live in Canada and my dad listens to CFRB 1010 (out of Toronto, Ontario Canada) on AM all the time. He stopped listening to it because it was so staticky. He uses a normal Cdn Tire radio, so I thought I would boost the signal for a birthday present....

What is your budget for this?

A really good thing to do before leaping to conclusions is to spend a little time understanding WHY the problem exists. (This advice extends beyond static on AM radios...) Is the static caused by some local noise-generating device(s)? Is it caused by thunderstorms? Can you characterize the noise better: is it impulsive, or just random "white" noise? Is it synchronized with the power lines, or not? Is the signal basically strong, but the noise overpowering it, or is the signal very weak and it's not taking much noise to overpower it? Finding an optimal solution depends, I think, on a good understanding the nature of the problem. From your posting, I don't have the feeling you're at that point yet.

Also, what do you have to work with? Does the radio in question have an external antenna input, or does it rely totally on the built-in antenna? Is it feasible to replace the radio itself? What are your constraints involving installing an external antenna? (Can it go outside up in trees, or will it be limited to being next to the radio itself--in which case there may be no significant advantage to an external antenna...?) Have you tried the radio in different locations and different orientations? (The built in antenna is undoubtedly directional, with a couple deep nulls; bad news if the station you want is in a null!) I notice that CFRB apparently has streaming audio on the internet (it doesn't seem to be making it through our firewall at the moment...); is that a possible way to deliver the signal to your dad? Can you think of other possible solutions to the basic problem of letting your dad listen to the audio he wants?

Cheers, Tom

I would like to spend around $20-$40. He likes that radio where it is, tucked away in a corner. He is set in his ways and won't use the internet or move the radio...the noise is an overpowering static and in and out (you know when someone walks by). You can hear the voices, but the static and white noise is so annoying it wouldn't be worth it. I don't know what is causing the static - other AM stations are fine and the FM is good (just tested it). He uses a speaker wire antennae that came with it attached to the unit. If buying a better radio would help, I would gladly do that. I didnt realise the scope and complexity of getting a radio station, so I thought a booster would just do the trick.

Here's something you can try. Get a spool of hook-up wire in some inconspicuous color. Strip the insulation off one end, and use the screw in the nearest electric outlet to ground that end. Wrap 5 or 10 turns of wire around the radio itself, as if you're making an electromagnet. Orient this winding so that it makes a transformer primary with the loopstick in the radio as the secondary. Run the other end of the wire up the wall, across the ceiling, and down, but line this "big loop" up edgewise to the station. Leave the other end dangle.

Antenna booster, two bucks and some labor. :-)

Good Luck! Rich

On a sunny day (Fri, 29 Feb 2008 23:17:54 GMT) it happened Rich Grise wrote in :

Nobody mentioned a ferrite rod? Get a cheap transistor with ferrite rod, turn for max signal min noise.

I like the idea, but as a birthday present, it is not exactly going to go over well with my dad - he will probably think I am trying to electrocute him!

What is a ferrite rod? How do they work?

On a sunny day (Sat, 1 Mar 2008 06:53:56 -0800 (PST)) it happened lytecap wrote in :

It is a rod made of compressed iron powder material, with a coil wound around it that is part of a circuit that is tuned the transmitter. These antennas grab the _magnetic_, not the electric field (as a normal wire antenna does). They are highly directional, and the good thing is: Almost all modern radios have one. It is absolutely possible that just turning your dad's radio 90 degrees will fix the problem if it has such a ferrite rod. But hardly a present, but should be tried. If it does not help grab some normal transistor radio and go there, and see what direction you need to turn it for best reception, then buy a nice transistor for him :-) Any modern radio back to the sixties uses a ferrite rod for AM medium wave and long wave reception.

transmitter direction of max sensitivity | | \\ /

L ========================////////====== ferrite rod

To the OP:

CFRB AM (1010 kHz) is a 50kW Daytime / 50kW Nightime station. The towers are at Lat: 43-30-15 Lon: 79-37-52.

Here is the daytime pattern:

Here is the night time pattern:

So back to my original question to you, where are you in relation to these patterns? Is reception better day or night, or the same? What city or town is the receiver located in (so distance calculations can be performed)? Can you reasonably expect static-free operation at this distance?

50kW is a fairly healthy signal by the way.

-mpm

... OK, one more idea for you, along the lines of identifying the static source. First, change the orientation of the radio, basically where it is right now. Do things improve? Next, take the radio to a different place in the house, and turn it over at least a 180 degree range, and try tilting it too, to see if the static goes away or gets much lower. Then if possible, take it to another house nearby--or if it runs on batteries, just down the street a ways. In other words, see if the static is really local, or if you are just dealing with a tiny signal. This is along the lines of what mpm is getting at, too. If you have only a tiny signal to work with, getting good reception likely won't be easy, because there's so much atmospheric noise in that frequency range anyway. If you're dealing with low signal strength, my recommendation is to get a good AM radio with an external antenna connection that will disable or bypass the internal antenna (that I'm assuming the radio in question has) and put up a decent antenna outside. "Decent" might be a long piece of wire, or a modest size loop properly constructed and installed.

The fact that you say the static varies as someone walks by suggest to me that it's being generated very close to the receiver, and you MAY be able to find the source and kill it. The fact that other stations come in fine suggest to me that the static source MAY be something like a microprocessor embedded in some electronic gadget nearby, generating hash over a narrow band of frequencies. Once again, understanding WHY the static is there may be 99% of the solution.

Cheers, Tom