PA0RDT (and such) vs. MFJ-1024

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Jim_Shaffer

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Does anyone have experience with both these antennas? I'm drawn to the PA0RDT-types due to their low cost, but I'm tempted to just bite the bullet and pay for an MFJ because I can get it from U.S. sellers. (Unless anyone has a U.S. source for a completely-built miniwhip -- so far I've been unable to turn up any such thing in searches.) A compromise, of sorts, would be to buy the miniwhip from overseas, and while I"m waiting for it to arrive, buy cable domestically and get it buried to my intended mounting location before the ground freezes. (An alternative NOT under consideration is the LF Engineering H-800 and successors due to higher price, wimpy RG-174 cable permanently connected, and stupid RCA connectors.)
 

ka3jjz

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Jim you might want to take a look at this...


Have you considered using a loop? They have a few advantages, like in the MW/LW band, being able to null out one station in favor of another and a generally lower noise floor. What radio(s) will you be using?

Mike
 

kd1sq

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I'd go for a genuine PA0RDT device - order it directly from him. (There are many clones to be bought but some of them are of questionable performance.) Cheaper and - when mounted properly - performs well. Look at the famous Twente SDR in the Netherlands, that uses one of 'em.

Here, I've been experimenting with the MLA30 and K-180WLA loops (both cheaply available on eBay) and the K-180WLA is definitely the better of the two and gives fair performance. You might take a look at that one as well.
 

ka3jjz

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There's also a MLA30 plus, and even a Facebook group that describes how folks are experimenting and modifying it - if you're into that....Mike
 

Jim_Shaffer

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The reason I wasn't considering loops is because I want something omnidirectional.

My receiver is an SDRPlay RSP Duo.

How does one go about ordering an antenna from PA0RDT himself? I'm unable to find him on a Google search. I did find one article which said that he has a new design which only requires 5V power so it can be run directly from the built-in bias-T in some SDRs, but again, I see no information on how to obtain one.
 

ka3jjz

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I would back track that article, maybe email the author and see what you can find out. I assume there was no contact information on this article, so that's your next best bet.

I found a good number of folks selling PA0RDT mini whips (more likely clones) on fleaBay. A bit risky, yes, but look at the positive feedback ratings. I kinda doubt PA0RDT does this direct - the demand would simply be too much to handle for one person.

Another possibility - though more expensive - is the Bonito Boni Whip. No doubt that a good Google search will come up with more...I see it's also available on the Amazon UK site.


And SWLing.com had something on this very antenna


Mike
 

ka3jjz

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Well look what I found - this is a far better place to ask about the PA0RDT antenna...


Mike
 

ka3jjz

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Someone please correct me here, but I read someplace - and I'll be damned if I can remember where - that if you take a small active loop like the W6LVP, mount it horizontally and give it some height, it basically becomes omnidirectional - although my suspicions are that it becomes it bit more like NVIS propagation.

If correct, then this is another way to 'hide' a loop, because in such a plane, it becomes a lot harder to see....Mike
 

MDScanFan

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The active probes are cheap enough so I think they are worth a try. Likewise, some of the loops are relatively inexpensive so I would recommend them as well.

For what it’s worth, regarding the directionality of active loops...I have owned a few active loops (Wellbrook, Pixel, W6LVP) and currently have the Pixel mounted on a rotor. I only notice appreciable directionality on MW and below. So depending on what you listen to the pattern of a loop may or may not be an issue. Above 2 MHz I do not notice directionality and the signals remain unaffected as a rotate the loop. Below 2 GHz the null is so sharp that 90%+ of reception directions are unaffected by the fact that it is a directional.

The biggest benefits I see for the loop over the probe are all related to noise. If local noise sources are an issue, then I would strongly recommend a loop over a probe. The probes are more sensitive to installation (ie grounding) to keep noise pickup low. Loops are more forgiving in this regard. I find the directionality of the loop is invaluable to nulling local noise sources even up to ~15 MHz. For example, my neighbors have a noise source (likely a plasma tv) that shows up at multiple parts of the HF spectrum and below. If I position the null of the loop towards my neighbors house it greatly suppresses the noise.

The reason I wasn't considering loops is because I want something omnidirectional.
 

ka3jjz

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Another advantage of a loop (especially if you are trying to be stealthy) is, unlike these mini whips and many wire antennas, loops should be mounted close to the ground. And you don't need a big rotor to turn it - the wind load is very light.

Mike
 
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