AR15.Com Archives
 antennae question AM, not ham
douglasmorris99  [Team Member]
8/4/2009 10:47:15 PM
OK, I am bunching you guys as radio heads and making an assumption you can help me out
I Listent to talk radio pretty much 12 hours a day,, as I am retired and live along, it is good company for me and keeps me up with the world.


I live in a rural area and I have 2 questions

1 there is a 300ft tower going up in the field across the road for an AT&T cell tower, will it effect my AM radio

2 is there an antennae I can use to increase my AM reception AT NIGHT?

guilty pleasure is Coast to Coast,,but the static on the strongest station is driving me nuts...

VRMN8R  [Member]
8/4/2009 10:50:55 PM
Im sure someone will be along to help you shortly.
ar-jedi  [Team Member]
8/4/2009 11:09:05 PM
Originally Posted By douglasmorris99:
1 there is a 300ft tower going up in the field across the road for an AT&T cell tower, will it effect my AM radio

in all likelihood, no.

Originally Posted By douglasmorris99:
2 is there an antennae I can use to increase my AM reception AT NIGHT?

what antenna are you using now?
what radio are you using now?
does the radio have the capability to accept an external antenna?
do you have space outside your house to hang a long wire antenna?
can you do so without irking, for example, a homeowner's association?

ar-jedi
A_Free_Man  [Team Member]
8/5/2009 1:33:06 AM
1 there is a 300ft tower going up in the field across the road for an AT&T cell tower, will it effect my AM radio Not likely.

2 is there an antennae I can use to increase my AM reception AT NIGHT? Yes.


A good tuned loop will do wonders for you. And tuned loop, not "long wire", etc.

A longwire needs to be a good fraction of the desired wavelength, and for the AM broadcast band (530-1700 khz) aka "MW" (medium wave), you are talking over 100 YARDS, not feet, YARDS.

For the AM band loops get the job done, don't have to be high (work even in a basement!), don't have to be very big, and work really well. What I'm going to tell you about is what used to be called the "Sport fan's loop". This was for guys that wanted to listen to the local game that was "blacked out" by tuning in a distant radio station that carried the game.

This is easy to make. First read my second post in this thread:

http://www.ar15.com/forums/topic.html?b=10&f=22&t=626138

The antenna I am about to describe is similar to this:

http://www.youtube.com/watch?v=l_keFgFYkO0 This is most like the one I have. Yes, the improvement in reception is just this dramatic.

You need a variable capacitor, valued variously as 9.6-365 pf, or 10-380 pf, or 10-400 pf. These are all the same. I gave one source on the link above. Get a mounting bracket and a knob, too.

You will need some 22 ga magnet wire, aka "enameled wire", like used for winding motor armatures. You can buy this at www.kenselectronics.com. You will need about 86', just buy 100' and be done with it.

Make a box frame 17" on each side, or 24" diagonal, and 2 1/2" - 3" wide. Wind on 15 turns of the wire with 1/8" spacing. You may want to saw (hobby razor saw, or dremel) notches in the corners to hold the spacing. One end of the 15 turn loop connects to any of the four tabs on the bottom of the tuning capacitor. The other lead connects to the frame of the tuning capacitor. I use a ring terminal under one of the screws on the mounting bracket. Bracket must be purchased separately. The tuning capacitor can be mounted on the frame, say, in a few inches from one corner of the box frame for the windings. Built to these dimensions, this loop will cover from about 480-500 khz up to about 2.2 mhz. That means it will cover the 160 meter (1.8-2.0 mhz) shortwave band, too.

(Note, a bigger loop will require fewer turns of wire. But bigger is not necessarily better. I've built a number of loops of various size for the AM band. There seems to be a point of quickly diminishing returns, and 24" diagonal seems to be that point. A 4' diagonal loop is barely any better than a 2' loop. If there is a difference in performance, it is difficult to hear. A 24" loop is somewhat better than a 12" loop, and not that clumsy, so in my opinion/experience a 24" diagonal loop for the AM band is about optimum.)

Place it beside your portable radio, turn your radio to the desired frequency, then adjust the tuning capacitor. This works just fine if you have a ferrite rod antenna in the radio. The loop antenna works with the radio's internal antenna via mutual coupling.

Experiment a little with placement of the loop antenna in relation to the radio. The loop is highly directional, which is good for nulling out noise or undesired stations, as well as picking up your desired station.

Some place the radio and the loop on an old "Lazy Susan" so they can rotate the radio and antenna together.

You will be amazed how this sucks in the signals.

OK, so you want to just buy an antenna. The Terk AM Advantage from C. Crane is pretty good. It is also a tuned loop, just smaller, and somewhat less effective, but works well. http://www.ccrane.com/antennas/am-antennas/terk-am-advantage.aspx

Youtube video http://www.youtube.com/watch?v=1cxHJHl2PaM

It performs similarly to the Select-a-tenna. C. Crane used to carry these. http://www.youtube.com/watch?v=HAXPfnuCwTg This guy is in his basement.

And if you are feeling flush, this is highly regarded: http://www.ccrane.com/antennas/am-antennas/twin-coil-ferrite-am-antenna.aspx

There used to be a Youtube video of the Twin Ferrite, too, but it is no longer there.

A friend uses an AM loop that I made for him in his basement. And I use one of mine in my house, and another out in my workshop with the stereo gear there. It is a metal building, well grounded, a virtual faraday cage. Yet the loop picks up well inside the building.


Tonkaman  [Member]
8/5/2009 2:02:03 AM
Pardon the hijack, but what about a DIY antenna for FM radio?
A_Free_Man  [Team Member]
8/5/2009 2:19:36 AM
Ahhh, funny that you ask...

The easiest is just use 40'-50' of insulated hookup wire, connect that to the FM terminal on your FM tuner (experiment with which one), leading out of a window, up to the edge of the roof. Use Christmas light clips and run the wire along the edge of the roof. If you can turn a corner with it, all the better, getting both some north/south and east/west signal. This will work FAR better than the little twinlead folded dipole antennas.

Do you have some 300 ohm "twinlead" or 450 ohm "ladder line"? Look at the various J-pole and Slim Jim antennas at www.hamuniverse.com and click Antenna Design on the left.

You can make a "roll up J-pole" like the 2-meter (145-148 mhz) roll up antennas, but make it longer for the FM band (88-108 mhz). I would use a ratio of 146/100 x the dimensions given for 2 meters, and that will scale it up for the FM band.

If you have some 1/2" copper tubing, and can solder (torch required), you can do this:

http://www.hamuniverse.com/jpole.html If you want general FM band coverage, enter 100 mhz in the calculator, and click {Calculate Antenna Dimensions} button. This antenna is outstanding for an omnidirectional FM antenna. The stub that is clamped to the mast... does not matter if it is insulated or not, or grounded or not. Just does not matter. You can use stainless automotive hose clamps and fasten to a roof vent, or any pole, TV mast, etc. Also, does not matter much if the shield is connected to the 3/4 wave segment and the center to the 1/4 wave segment, or vice versa. Some say hook it up one way, some say the other. Doesn't really make a difference.

After it is all soldered together, make sure you clean the flux off at the solder joints. Before you put the end caps (and you DO want to cap the ends) you may want to drop some segments of fiberglass fence rod into the copper tubing to stiffen it up a bit. Clean the entire antenna well with steel wool, then wipe down with some lacquer thinner, and finally, spray a few coats of clear spray lacquer. That will cut down on corrosion.

radiowave  [Team Member]
8/5/2009 2:29:47 AM
AM RF has different propagation characteristics at night, which you may notice in the form of interference from other stations on top of the one you are trying to listen to. AM stations will normally decrease their power at night because of this. You could be experiencing a combination of decreased power from the station you want, and increased range from the stations you don't want. An outdoor antenna may hurt in this case. Assuming your radio has a place in the back to connect an antenna, I believe that using a loop antenna could help you. Install the loop antenna, then change its orientation until things sound better. That is my first recommendation.
A_Free_Man  [Team Member]
8/5/2009 3:13:16 AM
Loops may be used with radios with internal antennas, such as you saw on those videos, with no wired connection.

If you have an AM/FM tuner or stereo receiver, you are not out of luck. Make a one turn pickup loop (or "sense loop") on the frame of the loop antenna next to the other 15 turns, and connect this via a twisted pair of hookup wires (say, 2 twists per inch or so), 300 ohm twinlead, or even coax. Does not matter in my experience. One lead will connect to the AM antenna terminal on your receiver or tuner, and the other lead (or if coax, the shield) will connect to the chassis ground terminal. This pickup loop will couple the main loop to your receiver.
Tonkaman  [Member]
8/5/2009 1:35:11 PM
WOW! Great information! I don't know what half of it means but I'll figure it out. Thanks a million!
VRMN8R  [Member]
8/5/2009 2:22:52 PM
Originally Posted By Tonkaman:
WOW! Great information! I don't know what half of it means but I'll figure it out. Thanks a million!


Be careful what you ask for at times.

These guys are way smarter than I am.

douglasmorris99  [Team Member]
8/5/2009 4:57:44 PM
gee guys, thanks for the help

just one thing..



I AM A COOK..not an electronics tech...

I am HANDY and Not all thumbs, but cluless in the terminology you are offering me here




let me rephrase the second question..and please Break it down for us simple folks...


WHAT ANNTENEA DO I BUY, that will help acentuate my on board, built in anteni on my bed side radion
and what one do I buy for my extrenal IN THE HOUSE antennea for my stereo system. II do have an external one on my stero, with about 3' of wire attached, I was even smart enough to fix the little thin tail of an FM antennea, the STATIC at NIGHT is killing my listening of a 5KW station 90mi away,


thank you in advance..
ar-jedi  [Team Member]
8/5/2009 6:24:27 PM
Originally Posted By douglasmorris99:
let me rephrase the second question..and please Break it down for us simple folks...

WHAT ANNTENEA DO I BUY


so let's back up a few posts...

Originally Posted By ar-jedi:
Originally Posted By douglasmorris99:
is there an antennae I can use to increase my AM reception AT NIGHT?

what antenna are you using now?
what radio are you using now?
does the radio have the capability to accept an external antenna?
do you have space outside your house to hang a long wire antenna?
can you do so without irking, for example, a homeowner's association?


ar-jedi
douglasmorris99  [Team Member]
8/5/2009 8:37:02 PM
Originally Posted By ar-jedi:
Originally Posted By douglasmorris99:
let me rephrase the second question..and please Break it down for us simple folks...

WHAT ANNTENEA DO I BUY


so let's back up a few posts...

Originally Posted By ar-jedi:
Originally Posted By douglasmorris99:
is there an antennae I can use to increase my AM reception AT NIGHT?

what antenna are you using now?
what radio are you using now?
does the radio have the capability to accept an external antenna?
do you have space outside your house to hang a long wire antenna?
can you do so without irking, for example, a homeowner's association?


ar-jedi




sorry I didnt answer the questions, got lost in the answers...
I live in 10 acres and my neighbor is a horse,,there is and never will be a HOA,,I will burn the house down and move first.

radio1 is a all in one stereo unit from sears, nothing special, has a detachable AM antennea that is wires wrapped around a square plastic "stand" this of course can be changed out with no issue, it is a bare wire connected into a bracket with spring levers this is probably an easy fix with the posted due it your self..I guess.

radio 2 is a nightstand basic clock radio, it has an external FM antennae only,

radio 3 is a grundig yaught boy, IT travels with me as a portable and it does have an external power source and an external antennae jack..this is probably the easist to cure with a commercial assessory?

thank you
A_Free_Man  [Team Member]
8/6/2009 12:51:22 AM
radio1 is a all in one stereo unit from sears, nothing special, has a detachable AM antennea that is wires wrapped around a square plastic "stand" this of course can be changed out with no issue, it is a bare wire connected into a bracket with spring levers this is probably an easy fix with the posted due it your self..I guess.


OK, the wire wrapped around the plastic "stand" is a simple, yet surprisingly good UNTUNED AM loop. They are broadband, that is, they don't have to be tuned. The problem with those, they are too small and no gain. Tuned loops have a lot of gain.

Since you don't want to build an antenna, but want to buy, look for the Terk AM Advantage or the Select-a-tenna. There is a version of the Select-a-tenna that has a 1/8" jack on the front just below the tuning knob. I think the item number has an "M" suffix. That version can be used as in the Youtube videos, just placed beside your radio, or a cord with 1/8" plug (a Radio Shack item) can be plugged in (that jack goes to a pickup loop inside) and the center/shield of the cord connected to the AM antenna terminals where you have your little plastic "stand" loop antenna connected now.

radio 2 is a nightstand basic clock radio, it has an external FM antennae only,
See my previous comment about the stranded insulated hookup wire leading outside. Barring that, 9'-10' of wire just stretched out indoors will do pretty well.

radio 3 is a grundig yaught boy, IT travels with me as a portable and it does have an external power source and an external antennae jack..this is probably the easist to cure with a commercial assessory?


Yes, the 1/8" external antenna jack can be connected with a 1/8" mono plug to 1/8" mono plug (I think they are 6' long at Radio Shack) cable will connect from there to the Terk AM Advantage's jack.

Again, for your home stereo receiver, AM, or your Grundig, the Terk:

http://www.ccrane.com/antennas/am-antennas/terk-am-advantage.aspx

http://www.universal-radio.com/catalog/mwant/2774.html

Terk AM Advantage:



These are small, work pretty well, about equal to the Select-a-tenna in performance.

Here's the Select-a-tenna.

http://www.universal-radio.com/catalog/mwant/4316.html If you buy the Select-a-tenna you want the 541-M.



To review, both the Terk AM Advantage and Select-a-tenna cover only the AM (MW) broadcast band, and are about equal in performance. The Terk smaller, lighter, more "modern" looking. The Select-a-tenna is clunky, ugly, but almost indestructable.

Now, for your Yachtboy, for SW, 80 meters (3.5 mhz) on up, this is the schiznitz... the Kaito KA-33 (I have the very similar, but earlier KA-31). These are easy to find on ebay. This thing works. It comes with all the cables, plugs you need. The photo shows only the little amp/tuner. There is a thumbwheel to adjust tuningm in that photo, just below the red LED.

http://www.universal-radio.com/catalog/sw_ant/3670.html

Here's the whole thing:



It comes with a ferrite stick coupler, if your radio has a ferrite bar antenna. It comes with a 1/8" plug such as you'll need with your Yachtboy. It also comes with two clips for terminals.

It says 3.9-22 mhz. I found that it would actually tune down to about 3.6 mhz, covering most of the 80/75 meter band. Again, this is for SW, not AM broadcast (MW).

The "telescoping antenna" in the diagram is not used as an antenna, but simply as a collapsable spreader bar to give the loop some shape. This whole KA-33 setup will fit in a heavy 1 qt ziplock freezer bag along with spare batteries with room to spare.



douglasmorris99  [Team Member]
8/6/2009 1:04:06 PM
Originally Posted By A_Free_Man:
radio1 is a all in one stereo unit from sears, nothing special, has a detachable AM antennea that is wires wrapped around a square plastic "stand" this of course can be changed out with no issue, it is a bare wire connected into a bracket with spring levers this is probably an easy fix with the posted due it your self..I guess.


OK, the wire wrapped around the plastic "stand" is a simple, yet surprisingly good UNTUNED AM loop. They are broadband, that is, they don't have to be tuned. The problem with those, they are too small and no gain. Tuned loops have a lot of gain.

Since you don't want to build an antenna, but want to buy, look for the Terk AM Advantage or the Select-a-tenna. There is a version of the Select-a-tenna that has a 1/8" jack on the front just below the tuning knob. I think the item number has an "M" suffix. That version can be used as in the Youtube videos, just placed beside your radio, or a cord with 1/8" plug (a Radio Shack item) can be plugged in (that jack goes to a pickup loop inside) and the center/shield of the cord connected to the AM antenna terminals where you have your little plastic "stand" loop antenna connected now.

radio 2 is a nightstand basic clock radio, it has an external FM antennae only,
See my previous comment about the stranded insulated hookup wire leading outside. Barring that, 9'-10' of wire just stretched out indoors will do pretty well.

radio 3 is a grundig yaught boy, IT travels with me as a portable and it does have an external power source and an external antennae jack..this is probably the easist to cure with a commercial assessory?


Yes, the 1/8" external antenna jack can be connected with a 1/8" mono plug to 1/8" mono plug (I think they are 6' long at Radio Shack) cable will connect from there to the Terk AM Advantage's jack.

Again, for your home stereo receiver, AM, or your Grundig, the Terk:

http://www.ccrane.com/antennas/am-antennas/terk-am-advantage.aspx

http://www.universal-radio.com/catalog/mwant/2774.html

Terk AM Advantage:

http://www.universal-radio.com/catalog/mwant/2774lrg.jpghttp://www.universal-radio.com/catalog/mwant/2774jack.jpg

These are small, work pretty well, about equal to the Select-a-tenna in performance.

Here's the Select-a-tenna.

http://www.universal-radio.com/catalog/mwant/4316.html If you buy the Select-a-tenna you want the 541-M.

http://www.universal-radio.com/catalog/mwant/4317.gif

To review, both the Terk AM Advantage and Select-a-tenna cover only the AM (MW) broadcast band, and are about equal in performance. The Terk smaller, lighter, more "modern" looking. The Select-a-tenna is clunky, ugly, but almost indestructable.

Now, for your Yachtboy, for SW, 80 meters (3.5 mhz) on up, this is the schiznitz... the Kaito KA-33 (I have the very similar, but earlier KA-31). These are easy to find on ebay. This thing works. It comes with all the cables, plugs you need. The photo shows only the little amp/tuner. There is a thumbwheel to adjust tuningm in that photo, just below the red LED.

http://www.universal-radio.com/catalog/sw_ant/3670.html

Here's the whole thing:

http://www.universal-radio.com/catalog/sw_ant/3670dia.jpg

It comes with a ferrite stick coupler, if your radio has a ferrite bar antenna. It comes with a 1/8" plug such as you'll need with your Yachtboy. It also comes with two clips for terminals.

It says 3.9-22 mhz. I found that it would actually tune down to about 3.6 mhz, covering most of the 80/75 meter band. Again, this is for SW, not AM broadcast (MW).

The "telescoping antenna" in the diagram is not used as an antenna, but simply as a collapsable spreader bar to give the loop some shape. This whole KA-33 setup will fit in a heavy 1 qt ziplock freezer bag along with spare batteries with room to spare.





thats the ticket, thank you
CHEF
Gamma762  [Team Member]
8/6/2009 2:16:46 PM
My sister wanted better AM reception and it was a very easy solution.

Ran an insulated wire down the length of the attic up in the rafters, down through the wall and attached to the external antenna connector on her radio. All the AM she ever wanted to hear and more.
douglasmorris99  [Team Member]
8/9/2009 8:30:40 AM
Originally Posted By Gamma762:
My sister wanted better AM reception and it was a very easy solution.

Ran an insulated wire down the length of the attic up in the rafters, down through the wall and attached to the external antenna connector on her radio. All the AM she ever wanted to hear and more.


no attic


doublewide


buts I gots the biggedest one in the neighborhod