I've never used a loop antenna, but the ones I have seen had a variable capacitor. Does anyone use an outdoor loop on a rotor and if so, how does one get past the variable capacitor?
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Outdoor AM Loop
- Thread starter BobOnTheJob
- Start date
R
rbrucecarter5
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BobOnTheJob said:
There are several good outdoor turntables you can buy at places like Home Depot and Lowes - it has been a few years since I've looked for one, though.
The way around the tuning capacitor is to use varactors instead, and send a DC voltage out to the loop to tune it.
I do use an outdoor loop, two to be exact, and neither one uses a variable capacitor. They are both commercial loops made by Wellbrook in the UK, and the 1530+ is coupled with a rotator. I also have a Wellbrook ALA100 that I bought for use when we are in rural Indiana. It provided tremendous results the one time I have been able to use it. Both of these antennas use a balun (I assume 4:1) to bring the impedence down to about 50 ohm. They also amplify the incoming signal. Both antennas are bi-directional, so a rotator only enhances the the signal grabbing capacity.BobOnTheJob said:
Do you want to build your loop? There are tons of sites with complete instructions for every kind of loop imaginable, and you can build your own balun, or buy one of the commercial versions.
Another supplier of "magnetic" loops is PK's loop antennas in Australia.
I've already found many antenna design/build sites, so feel free to pm me and I would be happy to send you the urls.
P.S. - If anyone wants a great and reasonably inexpensive DX radio, that is also on heck of a table top AM/FM Stereo, take a look at the Sangean PR-D5 AM/FM Stereo RDS Digital Radio. It has an 8" ferrite bar antenna and the circuitry is pretty much state of the art. At about $73, you can't beat it.
My teenaged buddy Vinny (yo!) back in Queens built, and operated, a diamond-shaped loop antenna in his yard, circa 1964, mounted on some pole in back of his garage, right out of the monthly magazine 'Radio-TV Experimenter'. Back in those dynasties, Radio-TV Experimeter was $.35 a copy.
Keep in mind : Ours was a real grass-roots Archie Bunker neighborhood, with very little property. We all were packed like sardines. I think the plots for the houses went something like 20 feet by a hundred feet.
Vinny's antenna had *fixed* capacitors at various windings within the same diamond-shaped antenna structure. Much like a car radio's tuning capabilities went. The first one was 600 kHz. I forget the other tw settingso.
The outdoor loop cooked.
Keep in mind : Ours was a real grass-roots Archie Bunker neighborhood, with very little property. We all were packed like sardines. I think the plots for the houses went something like 20 feet by a hundred feet.
Vinny's antenna had *fixed* capacitors at various windings within the same diamond-shaped antenna structure. Much like a car radio's tuning capabilities went. The first one was 600 kHz. I forget the other tw settingso.
The outdoor loop cooked.
Icangelp said:
This.
I got one of these back in the summer and I have been thrilled with it. I've brought it with me to college and it's been great. Dorm rooms are notorious for bad AM reception and the PR-D5 does not solve all of those problems, but in my window it manages to pull in stations very well.
Anyone have a lead on an American made AM loop similar to the Wellbrook? With the poor dollar/foreign currency exchange & high shipping cost, the Wellbrooks are a little steep now.
extremely simple indeed - just alligator clip the ends of the coil to the capacitor leads, and place the radio near the conductors somewhere (or clip it on directly to an ANT input)Tom Wells said:
the main tricky part is getting resonance where you want it - wire spacing can make extreme differences
in both the Q and the resonant freq..
a 6x8x2 inch Amazon box with 1cm spacing roughly tunes around 1.5-4 mhz with a cap
2 layers of flush singlestranded speakerwire on a 200mm ferrite from an reciever resonates around 160-450khz - great for longwave beacons, and the european broadcasters
I just took the plunge & ordered the Wellbrook outdoor loop that operates from 50khz - 100mhz with an outdoor preamp and no tuning required (that was the clincher for me). Been using a 110' vertical long wire with so-so results, but when lightning popped my Icom IC-R1500, the high price of the Wellbrook suddenly started looking better. The vertical was DC grounded where it left the 240' support tower and again where it entered the Icom...time to go for something a little less inviting to lightning.
Did you order the ALA100M or a 1530 version?
I am very happy with my 1530+, and even decided to buy a rotator so I wouldn't have to go outside to change the antenna direction. Proving to be a wise decision these last few days.
Try to mount it a reasonable distance from your home. Mine is about 18 feet from the SW corner of our house, and I still get interference on certain longwave frequencies when the antenna is directed towards the house. Home is loaded with dimmers and computers, and my wife is usually sitting in that corner with her laptop. Plus, my neighbor is a power tool freak.
I am very happy with my 1530+, and even decided to buy a rotator so I wouldn't have to go outside to change the antenna direction. Proving to be a wise decision these last few days.
Try to mount it a reasonable distance from your home. Mine is about 18 feet from the SW corner of our house, and I still get interference on certain longwave frequencies when the antenna is directed towards the house. Home is loaded with dimmers and computers, and my wife is usually sitting in that corner with her laptop. Plus, my neighbor is a power tool freak.
wellbrooks are wideband amplifiers on wideband loops - varying general tunings
with a tuned loop you don't need an amplifier, since theres so much signal in the resonant peak
there are a number of these for MW. you can build your own with a milk crate, 40 meters of wire, and a capacitor..
with a tuned loop you don't need an amplifier, since theres so much signal in the resonant peak
there are a number of these for MW. you can build your own with a milk crate, 40 meters of wire, and a capacitor..
It's the 1530 North American version. I was planning on putting it on the roof about about 15' above the living area...doubt I'll brave the cold Indiana winter to add a rotor, but that's a Spring goal. Seems you're 80 miles east of me in Cincinnati...can you give me some daytime examples of what turning the antenna can do? And how well do you hear the Indiana stations on 1260, 1310, 1330, 1390, 1460 (that might be a good one 1460/North Vernon vs 1460/Columbus,OH) and 1580?Icangelp said:
I'l do it! (You forgot WSLM, my favorite old time station.) I work during the day, so I won't be able to check the daytime signals out until the weekend.
What I've found is some signals register weaker S9 readings than on indoor ferite loop, however man and nature caused "noise" is way down. That combined with the antenna's nulling ability, results in signals some great DXing.
I can also tell you that when I rotate the 1530+, I can null WCKY/1530 enough that the the adjacent channel slop is gone and the frequencies are listenable, not bad considering WCKY is 5.5 miles from my house. I don't benefit from WCKY's night pattern either.
Works well on WLW also.
What I've found is some signals register weaker S9 readings than on indoor ferite loop, however man and nature caused "noise" is way down. That combined with the antenna's nulling ability, results in signals some great DXing.
I can also tell you that when I rotate the 1530+, I can null WCKY/1530 enough that the the adjacent channel slop is gone and the frequencies are listenable, not bad considering WCKY is 5.5 miles from my house. I don't benefit from WCKY's night pattern either.
Works well on WLW also.
Of course...WSLM. WSLM-FM is on 97.9 and a swing of the FM yagi allows WSLM/Salem or WGNR/Anderson. For the record, WSLM still airs the Tick Tock Tick Tock it's xx O'Clock time jingles. And Don Martin is still on the air...talk about a legend. I look forward to your reports...sounds like the nulls are quite substantial.Icangelp said:
Did you get a chance to play with those daytime nulls?Icangelp said:
If that thing picks up WSEZ (coincidentally, I was working at WSEZ today) with WCNW on 1560, I'll be impressed.Icangelp said:
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