PA0RDT Active Mini-Whip Ant. ?

[BOBRR]

Hi,

Came across some articles and info on a PA0RDT active mini-whip antenna.
Sure is small.

Anyone using, or anything similar ?

Would sure appreciate any thoughts or comments on how this might compare
to my present receive only ant mounted outside the house.

It's a simple long wire ant. of about 75 feet length.
Works, but would sure like to find something "better".

I do receiving only, pretty much most anything <30 MHz.
Have a SDRPlay RSPdx, and use SDRConsole software program.

The mini whip, if we do get one, would have to be mounted in an upstairs study room, on the second floor of a typical
Colonial style house..
Too old now to play with putting and mounting outside.

How do you think it would compare with my present outside long wire ant. <30 MHz ?
Worth considering ?

Any thoughts would be most appreciated.

Regards, stay well,
Bob

 

[MDScanFan]

That antenna will most likley worse than your current antenna. That type of antenna is best suited to be mounted outside away from noise sources and grounded. Inside I think it would pick up too much electrical noise.

My recommendation would be to try an active loop antenna. They are much more resilient to nearby noise and they can be positioned to null out noise if it is coming from a particular direction. If you want to test the waters then you could try the MLA-30+ loop antenna for ~$50 from ebay. Other more expensive options include the W6LVP, Wellbrook, Pixel loop, etc. I have an active loop mounted outside and one mounted inside near my bedside. The inside antenna works pretty well. It picks up much more noise than outside antenna but its not too bad. I can rotate the antenna to minimize noise. It receives much better (less noise & more signals) than a whip on the radio.

 

[BOBRR]

Hi,

Thanks for thoughts on this.

I have a YouLoop loop ant.
Big disappointment.

Supposedly they are coming out with an amp for it.
Perhaps that might help, if they ever do.

Will look into the MLA-30.

Thanks again for suggestions,
Bob

 

[Patch42]

I agree with what MDScanFan said about the PA0RDT. It needs to be away from the house and above nearby obstructions. I used one for about a year when I lived in Florida. At the time you could get heavy duty fiberglass poles originally used with camouflage netting pretty cheap on ebay. I put together a few of those, put the PA0RDT at the top, and zip-tied it to one of the support poles on the screen room in the backyard. Running the wire back to the house was by far the most difficult part.

Even the loops are going to work much better if you can get them out of the house. They usually don't have to be mounted high to be effective, so you can do an installation that won't require large masts. I also have a Wellbrook loop. It works inside the house but not remotely like it does if I get it just ten feet from the house.

 

[ka3jjz]

In fact there is an article at SWLing.com about the proper grounding and placement of a mini-whip

How to properly install a Mini Whip antenna in an noisy urban environment

Many thanks to SWLing Post contributor, Grayhat, who shares the following guest post: Setting up a Mini Whip antenna by Grayhat I’ve been fiddling with my “balcony antenna” experiment for quite a w…

swling.com

Don't try to compare a YouLoop to any loop like the MLA30+. They are 2 different animals - the YouLoop is passive (no amp) and very small and are largely dependent on the radio to amplify the signal Not so with loops like the MLA30+ which has an amplifier.

The MLA has got an extensive following on Facebook where folks have been playing around with making improvements. If you are a tinkerer and have the MLA30 or 30+ then you should be here...

Facebook

www.facebook.com

Mike

 

[dlwtrunked]

Hi,

Came across some articles and info on a PA0RDT active mini-whip antenna.
Sure is small.

Anyone using, or anything similar ?

...

I am going to disagree with what some others may tell telling who have never tried one. I have both wire antennas and a PA0RDT on my house roof. For lower frequencies, it is my go to antenna. Some designs though do fall off as one goes higher on HF. The PA0RDT is a time proven good design when properly placed and will often outperform a wire antenna at many space restricted locations. Given enough space, it is true you can put up a better antenna. They will tell you that you need to get it away from noise sources--of course that is true for any antenna and easier to do for a small antenna but can still be a problem. Get it high and clear (some put one in a tree) and it works amazingly well - particularly at VLF and LF--yes, VLF and LF (and will likely out do your wire there--I speak from experience on that). It is the antenna used by the well-known Twente web radio. You can buy these cheap (so cheap there is no reason not to buy one and try it) on eBay and yes they work. If you have interference problems, that is another issue and extra gain will not help. I keep one in the car with a rope so I can put it in a tree when I want. I have even put it on the car roof (not a good location) and been able to receive WWVB on 60 kHz and NAA on 24 kHz (car turned off to stop ignition noise and even had to turn off the Garmin.

 

[BOBRR]

Hi all,

Thanks everyone for such good info.
Nice of everyone to take the time.

Will likely get the Loop ant. MLA-30.

a. What is the (pretty exact) Diameter ?

b. Am I correct that I can "simply" power it via a USB cable plugged into my pc ?
If so, can/does a USB provide enough power ? Or better to get a small power supply for ?
The USB would sure be easier, and cheaper.

Have seen diagrams, but I am still a bit confused over orientation.
That old-age problem again.

My understanding is that the plane of the loop should be vertical.
And that the sensitive axis is Z"also" the plane of the loop.
Correct ?

Thanks, stay well,
Bob

 

[MDScanFan]

Documentation lists the diameter at 60 cm.

Regarding powering, it is intended to be powered by any USB power source, such as a PC, wall wart, etc. It may be worth trying a couple different sources to see if one of them provides lower noise.

At lower frequencies (<~2MHz) the loop is directional with a null perpendicular to the plane of the loop. At higher frequencies (>~2 MHz) the antenna is mostly omni. The null can be pointed toward noise sources to help with noise. Loops are typically installed vertically such that the plane of the loop is up and down. Once you get the loop I suggest playing around with placement and orientation. A few weeks back I played with loop orientation in a bedroom. While testing against ~3.5-14 MHz signals I noticed no appreciable difference in average signal levels and number of signals received when the loop was vertical or horizontal. The primary difference in the two orientations was the impact of local noise sources so I picked an orientation that minimized noise.

Hi all,

Thanks everyone for such good info.
Nice of everyone to take the time.

Will likely get the Loop ant. MLA-30.

a. What is the (pretty exact) Diameter ?

b. Am I correct that I can "simply" power it via a USB cable plugged into my pc ?
If so, can/does a USB provide enough power ? Or better to get a small power supply for ?
The USB would sure be easier, and cheaper.

Have seen diagrams, but I am still a bit confused over orientation.
That old-age problem again.

My understanding is that the plane of the loop should be vertical.
And that the sensitive axis is Z"also" the plane of the loop.
Correct ?

Thanks, stay well,
Bob