AM Antennas

I'm looking for an AM antenna to pick up a weak, fringe, and problematic AM station on my GE Superadio. What would you spring for, a Select-A-Tenna, or maybe this tunable loop? http://cgi.ebay.com/Tunable-Loop-An...itemZ9706280648QQcategoryZ16702QQcmdZViewItem

Or maybe some other options in about the same price range. :scratch2:

The Select-A-Tenna does a pretty good job in helping to capture those elusive signals. They make a few different versions of them. Personally, I prefer to use a longwire that I installed in the attic. The C. Crane AM antenna is suppose to be pretty good too. Here's a place that has several to choose from: http://www.universal-radio.com/catalog/mwant.html

I once made an antenna with a + frame that was 4' x 4' and had 7 odd turns of wire spaced over about 2-3" . It had a turn or two that was wound next to the main (was parasitic) and was tuned with an AM variable cap then connected to the reciever. I was picking up stations at night that were 5000km away!

The Select-a-Tenna is good for its size. I picked one up very cheap at an antique radio fleamarket; otherwise it's kind of pricey. Building a good loop is easy and fun (well, relatively easy and fun)... there's a loop antenna group on Yahoo, and if you search AM or BC loop antenna on Google, there are several good sites with plans, designs, and suggestions.

Loops are cool...

I did find some good sites awhile back such as this one - http://www.schmarder.com/radios/misc-stuff/loops.htm
but I'm looking to buy something fairly cheap to get me by since I'm so busy with home upkeep and DIY to have a fun project right now.

75' long wire pointed towards the station that should work.

Well AM Broadcast band is supper low. for a half wave dipole you would need approximately (I knew the formula when I got my License ) ft.
Make your wire is as long as possible, your talking hundreds of feet for that wavelength. Your not going to be able to do thatin all practically so just make it your long wire long! Oh and if you want to get real technical use a balun and ladder line. Keep those impedance and SWR factors in mind.

:thmbsp:

basically off the top of my head, a full wave length in the AM broadcast band is between 500 to 1000 ft depending on if your High or Low in the band. I know a full wave for my 160 meter rig is ridiculous, and AMBB is even lower, so the antenna is even bigger.

When I was 16 or so I decided that I wanted to get to understand the 2 most tricky things in my world. Antennas and girls. well way back when, not too too long ago, I mastered the antennas. Then I tried to tackle the girls. Well the girls are impossible as we all know and in my frivolous attempts at the impossible, I managed to forget more about radio communications and science then I ever learned about chicks. Damn!

Don't learn till' your burned.

The long wire antenna, the dipole and the quarter wave vertical are examples of antennas that access the electrical portion of an electro-magnetic wave. Loop antennas (not electrical 1 wavelength loops), are magnetically induced. It is important that they be smaller than a wavelength. They need to see the wave as it comes (not all at once) so that there is a changing magnetic field within it. The dipole may be theoretically ideal, but the loop is the only way to make do with limited space and still have an ideal (not compromised) antenna.

Hell for that matter build a quad. You'll get allot of gain, good rejection and dual polarization. But in all reality A stacked 5/8 wave is the best you can get. LOL.

Do you think France will loan me their Eiffel Tower. :scratch2:

Two I have looked at:

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

and

http://users.mcleodusa.net/m/mgodar/MDL10.html

I ordered the Godar Model 10 AM antenna and Godar FM-1A FM antenna.

http://users.mcleodusa.net/m/mgodar/FM1-A.html

I plan on putting the FM-1A in the attic. (UPDATE-done, works well there)

Both are available on eBay new. The FM-1A is available from Parts Express as part number 210-090.

Will let you know how they work when I get them in a few days, but reviews I have read look promising.

UPDATE-The FM1-A works well in the attic, much better than down near the stereo gear.

The Model 10 AM did not work at all. I mean nada, zip, zilch.

Antennas are as much of a black art as they are science, I feel like, anyway.. You can put 60' of antenna running towards one side of yr lot, & it'll barely pick up diddleysquat, move it 90 degrees the other way, & you can pull in the ballgames from Jupiter. Try to get one as high off the ground as you can, KEEP AWAY from power lines-of course, that will be the direction the damn thing works the best-, & if you aren't satisfied, keep experimenting until you are. Radio Snack made a VERY good tunable loop-naturally, they discontinued it a couple years ago. I rigged mine up to one of my mighty R-390As, & it did a very good job.

Let's see, 1000' long. I wonder if I can simply run it around the house lot a few times. Wonder if wifey would notice. Maybe a reason to install a wood fence around the lot - makes for a good standoff. The take what, maybe a 20' groundrod and drive it into the ground. If nothing else that crystal radio should pick up the local station.

As a young'n, I connected my crystal set antenna leads to a large steel garage door with a water pipe to ground. The reception was so good that I couldn't understand why my mother wouldn't let me take the family stereo outside. :tears:

I have read about putting long wire antennas around property boundaries and it seems to be that they should go around only three of the sides, as after all it would be better if it were straight. One suggestion was to use the house guttering provided it didn't go right around in a continuous loop. Hmmm, I'll get some hacksaw blades while I'm out :yes:

Received the Godar FM1-A yesterday, the Godar Model 10 AM today.

FM1-A

First thing I suggest is experiment with hookup. I tried it on two units...

Bedroom unit Onkyo TX-850 receiver.

No coax jacks on the back, just 4 binding posts. Two are for 300 ohm (twin lead) for FM. One is ground, and the remaining post is AM antenna. From what the instructions indicate, proper hookup of FM twin lead (300 ohm) is between the two FM posts. For hooking 75 ohm coax directly to the receiver, to one FM post (labeled both for 300 ohm and 75 ohm) and the ground post. For AM loop, connect to ground post and AM post. Longwire only, to AM post.

First thing I did was connect the supplied 6' coax to the antenna, and screwed the balun, or transformer on the other end. I tried hooking both transformer leads to the two 300 ohm posts, but found a better FM signal was obtained by simply connecting one lead only.

The other unit, in the living room I have separate components in an entertainment center. The tuner is an Onkyo T-4000. The specs appear to be identical to those of the Onkyo TX-850 receiver, and the antenna connections are identical.

I found the best signal with this tuner was to connect both leads from the transformer to the two 300 ohm posts on the tuner. I then cut off the end of the coax, tossing aside the transformer, and stripped back the end. I soldered lugs to the center lead and shield for better connection to the binding posts. Connecting the center to the 75 ohm post, and shield to ground gave the best FM signal yet.

Now for the Model 10 AM. It comes with a 6' coax and transformer also. Again, on the TX-850 receiver I found the best signal with only one lead connected. That is all I tried. On to the tuner in the living room.

With two leads from the transformer connected to ground and AM posts there was almost no signal. Disconnecting from the ground post gave much better signal, but only when I held the antenna. The signal was stronger if I was near the antenna, or better, holding it. I got a GREAT signal if I touched the metal nut that screwed to the coax jack on the antenna.

A quick read of the instructions.... I tried just a length of 22 ga insulated wire, each end stripped about 1/2". One end hooked to the AM post on the tuner, the other inserted into the coax jack on the antenna... better.

This AM antenna worked only if I held it in hand.

Back to the FM antenna. I think this Godar FM1-A will be even more improved once I move it to the attic.

I set the tuner on FM to what I knew was a distant weak station. Turned the Mute off and got nothing but faint static.

OK, just got out of the attic... I already had coax run up there. Hooked the FM1-A to the coax in the attic, and just laid it down on the fiberglass insulation. Hey, I have a signal on that distant station (about 50 miles away)... not much, but I can hear it. A little noisy but it is there.

OK, tuning up and down the FM band, I am well satisfied with the FM. The AM, I feel could be better. Of course, I was getting nothing before. Probably a 50' or 100' roll of 22 ga hookup wire to the AM antenna, and a good ground would probably be as good as you can get for AM.

For AM only: Most money efficient antenna is a plain long wire. As long as you can get it. Out the window, into some trees, longer the better. Select-a-tenna is also good from C.Crane. They also have a twin ferrite tunable that you can mount on a pole and turn for best signal. I do most of my AM listening with a Drake R8B, a Sony ICF 2010, and a C.Crane "CC Radio plus". With common ownership, and syndicated talk radio everywhere AM DXing isn't as rewarding as it used to be. Who needs to get Art Bell on 20 stations when the local station has the best quality?

Ok, if you do choose to go with the long wire, it will have a poor SWR if not the full length, but this can be alleviated with an inductance at the reciever in series with the wire, maybe begin with a helical section of the wire.

Well, the Godar AM just DOES NOT WORK. I found that if I disconnected the coax from the Godar Model 10 I got a much better, but still crappy signal. Yes, signal increased without the antenna. Sent it to Mike at Godar to check out, but I think it is a design flaw.

UPDATE- Godar just sent me an email that they will send me a new and improved version of the AM antenna in a few weeks.

I have read a lot of good stuff about various loops, especially the Selectatenna from C Crane.

I read about "the Ultimate AM Loop" and was about to scrounge materials to build one, but stumbled on a guy selling these on eBay, both kit and complete.

article:

http://members.cox.net/rwagoner/columns/am_antenna.html

kit:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9720387500

built:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9719181129

You know those big 1 1/2 gallon jugs of liquid detergent? Just for grins I took a big blue Cheer jug, cut off the bottom section about 3" up from the bottom.

I washed it out, wrapped 5 turns of 18 ga magnet wire from an old inductor. To the ends of the loop I attached two pieces of insulated hookup wire, 3 feet long and twisted together, and to the AM terminals of one of my receivers.

No science, no calculating, nothing. I guessed at the number of turns. Have not tried more or fewer turns. No fine tuning at all. Like Nike, just do it.

I am in southern Louisiana. I am picking up WWL 870 in New Orleans, KWKH 1130 in Shreveport, LA (opposite end of the state), WOAI 1200 in San Antonio, TX, KMOX 1120 in St. Louis, MO, WLS 890 Chicago, IL, and many, many others. Not just barely picking up, they are clear. You can hear all the details of the ballgame in San Antonio but the crowd is a little loud.

OK, WLS and KMOX are a little noisy, but not bad at all.

(Add to this list WBOP 820 in Ft. Worth, TX and KLVI 560 in Beaumont, TX, which is only 5000 watts)

I think the signal is so clean overall because I used a soap jug.

This antenna actually works, unlike the Godar Model 10. No science, no tuning, no nothing. Just hooked it up and it works. 5 minutes to make.

I saw the jug in the trash can. From idea to listening, about 15 minutes.

Why can't antenna manufacturers do as well?

Geez - make it look easy, will you!

I've spent 10 hours calculating a loop, building a wooden frame, wrapping it with a 10 turn coil attached to a 30 - 750 pF variable capacitor ($17 delivered plus a $2 knob), with a one turn pickup coil. Hook it up to my Sony STR-6060F and what do I get? Static, loud and clear.

No change in signal strength, no directionality, no effect from tuning the capacitor.

Actually it is not static but rather noise interference. Maybe it is the florescent lamp?

Tomorrow I'll woop it.

Must be my soldering.

You shoulda used a soap jug.

Seriously, I think it's those capacitor thingies that mess you up. To many parts.

:scratch2: