Got an MLA-30

SpaceForceCmdr

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I was using a long wire in my attic attached to a whip which fed downstairs. The MLA came today, and I put it on a 1" PVC pipe, and built a small base for it our of shelf brackets and band clamps. I think it worked out pretty well. At the moment, it's up on the second floor near a window. Only complaint I have is that there's no way to disconnect the cable at the loop. I'd like to try it outside, but I have the cable run down through the wall, and it'd be a pain to undo/redo it.

As far as functionality, I think it's better than my indoor wire. I tested a bunch of signals from 30000 and down, and in most cases, the loop delivered a better SNR than the wire. In a few cases, the wire seemed to be better. In general, I'd say I was getting 5-10 dB better SNR with the loop, and I think the noise floor may be slightly lower. I'm a newb to all this stuff, so take this all with a grain of salt.

So, for 45 bucks, I think it's a pretty good deal. Not a huge improvement over my wire setup, but in most cases it does seem to do a little better. I'm sure if I put it outside it'd do even better. As far as adjusting it, that was a pain, too, since it's upstairs and my PC is downstairs. I ended up grabbing my laptop, remoting into my desktop, and then taking the laptop upstairs so I could watch my SDR as I moved the antenna. There were definitely big swings in reception depending on the orientation.

Here it is for now. I only use this upstairs area for storage, so I'm not concerned about it looking weird or getting in the way.
 

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MDScanFan

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There are a couple videos on youtube where people have cut off the cable at the amplifier box and added a connector. That way they can use their own coax run between the amplifier and power inserter.

I suggest trying a test case with the loop outside to see how much reception improves. At my location I notice a significant SNR improvement getting the loop outside vs my bedroom or attic.
 

popnokick

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... so I could watch my SDR as I moved the antenna. There were definitely big swings in reception depending on the orientation.
If you get a rotator those big reception swings will be your friend when you are trying to peak a desired signal or null out interference.
 

K3HY

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I was using a long wire in my attic attached to a whip which fed downstairs. The MLA came today, and I put it on a 1" PVC pipe, and built a small base for it our of shelf brackets and band clamps. I think it worked out pretty well. At the moment, it's up on the second floor near a window. Only complaint I have is that there's no way to disconnect the cable at the loop. I'd like to try it outside, but I have the cable run down through the wall, and it'd be a pain to undo/redo it.

As far as functionality, I think it's better than my indoor wire. I tested a bunch of signals from 30000 and down, and in most cases, the loop delivered a better SNR than the wire. In a few cases, the wire seemed to be better. In general, I'd say I was getting 5-10 dB better SNR with the loop, and I think the noise floor may be slightly lower. I'm a newb to all this stuff, so take this all with a grain of salt.

So, for 45 bucks, I think it's a pretty good deal. Not a huge improvement over my wire setup, but in most cases it does seem to do a little better. I'm sure if I put it outside it'd do even better. As far as adjusting it, that was a pain, too, since it's upstairs and my PC is downstairs. I ended up grabbing my laptop, remoting into my desktop, and then taking the laptop upstairs so I could watch my SDR as I moved the antenna. There were definitely big swings in reception depending on the orientation.

Here it is for now. I only use this upstairs area for storage, so I'm not concerned about it looking weird or getting in the way.
That indoor base looks nice as well.
 

SpaceForceCmdr

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There is a FB group that discusses all sorts of mods to this little loop.


Mike
Thanks, will check that out!
 

SpaceForceCmdr

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That indoor base looks nice as well.
Thanks! It worked out pretty well. I wanted to just make some PVC legs, but I couldn't find any attachments that would work, at least not at Lowe's, but the brackets did the trick.
 

SpaceForceCmdr

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So, just to update: I'm not really loving this antenna after all. I did some back to back testing, and it's actually not doing better than the long wire in my attic. In a few cases, I do get a slightly higher SNR, but not many. Not sure if testing in the afternoon vs night matters. Anyway, Here's a few example. For AM, the wire (which is in my attic) works better. Next, I tuned up to 9940 khz, and again, the wire did better.

Also, I should mention that I did put the loop antenna outside in my backyard for these tests, and it still lost. Not sure if I'm missing something, or the loop is just not so hot. For my purposes, the wire in my attic is pretty sufficient. As a bonus, I can tune up to the air band when the wire is connected, and get signal. With the loop, it picks up nothing there (which I can't really hold against it, since it's designed range is only 100-30000.
 

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ka3jjz

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Loops are directional below 3 Mhz or so, depending on the design. You will find that if a signal isn't coming in below that frequency, turn it and you might have a chance. This is their main advantage for lower frequencies where it can be hard to get a decent antenna without having a lot of room with which to work.

Yes time of day makes a big difference. The higher freqs, which tend to be less noisy, are only open during the day. The lower freqs, which open up after the sun goes down, tend to be noisier.

This is really a tinkerer's antenna. I'm fairly sure I saw something on the FB group that substituting that thin wire loop with coax did make quite a difference. And there other improvements one can make on it......Mike
 

SpaceForceCmdr

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Thanks! Well, I do have it now, and it was cheap, so I may experiment with it some more. For how cheap and easy it was, the copper wire stretched across my attic isn't bad. I'm wondering if I can tinker tinker with that as well. With these long-wire antennas, does the length need to be in a straight line, or is there a way to make it effectively longer? I have plenty of roof in the attic, so I'm wondering if instead of just running it once from end to end, what if I ran one piece back and forth a few times? Then, it could be two or 3 times longer, but still somewhat compact. I'm guessing it probably needs to be straight, though?
 

ka3jjz

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Receive antennas really aren't critical if you are just using random lengths of wire; never bend them in a U shape because signals could potentially cancel out. And of course, the longer the antenna indoors, the greater the noise pickup. Some folks have put up a PAR EF-SWL in their attic with some success. Again this is another tinkerer type antenna, as the connection box has some ports you can fool with to try to improve things. Of course you wouldn't be able to actually ground it.

However if you're just working with a portable or a SDR like a RTL-SDRv3, too much wire is too much antenna. Overloading - where signals show up where they don't belong, even AM or FM stations too - can be a problem. If you are on the East Coast. this is far more of an issue than if you are out in the middle of the Plains with few stations around you. Only you know your RF environment (or at least, you should). There are ways around this, but without any knowledge of your budget, it's hard to say one way or the other.

Here is one extreme example - one that's likely better suited for a ham transceiver (which nowadays have very capable general coverage radios) or true desktops like the NRD receivers...


And here's just a couple of other examples




Really if you want to get into antenna experimentation, there are a lot of books by the ARRL and the Radio Society of Great Britain which are excellent references.

Mike
 

SpaceForceCmdr

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I did play around with my MLA-30+ a bit more, and also got a Youloop for the heck of it. On certain SW freqs, mainly broadcasts, I seem to have an issue with RFI (my antenna is indoors). I get a pulsating, low-freq hum and some of the stations, and it's very annoying. The loops to help a lot with that. However, the MLA-30 also increases the noise level quite a bit, so the hum is cleaned up, but there's a lot more static and hiss. The Youloop really doesn't seem to do much at all. When I connect it to my feed line, the signal is not much stronger than with no antenna connected.
 

ka3jjz

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The YouLoop is really meant for SDRs which have a front end that is often too hot for its own good, so your results are not unexpected

Mike
 

SpaceForceCmdr

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Thanks, that makes sense. The MLA-30 works better for me, but the noise floor is not so great. I guess there is a Facebook group for tweakers, so I'm going to see if they have some suggestions on how I can improve it.
 

KB2GOM

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Thanks! Well, I do have it now, and it was cheap, so I may experiment with it some more. For how cheap and easy it was, the copper wire stretched across my attic isn't bad. I'm wondering if I can tinker tinker with that as well. With these long-wire antennas, does the length need to be in a straight line, or is there a way to make it effectively longer? I have plenty of roof in the attic, so I'm wondering if instead of just running it once from end to end, what if I ran one piece back and forth a few times? Then, it could be two or 3 times longer, but still somewhat compact. I'm guessing it probably needs to be straight, though?
I've had good luck with this: Jock designs a Horizontal Room Loop to cope with reception issues

Which I tweaked with this: The Satellit 800, the Tecsun PL-880, and two indoor antennas – an afternoon of experimentation

Like you, I thought maybe running more wire over the same route would result in an improvement. It did not, but adding an 9:1 unun and a ground connection did. Like you, I am running an indoor antenna for HF reception.

And this: Jock gets a good grounding!

And, finally, I found that this -- though expensive -- works pretty well for dealing with noise: Jock reviews the BHI Compact In-Line Noise Eliminating Module

Please note: I am not claiming that this is the ultimate setup for SWLing; I'm simply trying to deal with, and improve on, antenna limitations at my location.
 
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