Schematic of the modified HDLA phased loop array…

Ok, so here it is. Compared to the system used last season, the two loops will have a somewhat larger curcumference. On each loop the HDLA-amplifier/matching unit will be connected in the lower apex facing the desired listening direction. In my case, I want to favour reception from northwest and northeast and everything in between. In the lower apex of each loop, facing undesired directions, a 1 KOhm terminating resistor is connected. This will (hopefully) attenuate noise from nearby buildings and unwanted signals and QRM from southwest and southeast.

As you can see, the system can be defined as two phased KAZ-loops. Both loops are mounted on the same pole, in 90 degrees angle from eachother. This is far from ideal, but due to lack of poles and real estate, I don’t have any other choice than to do it like this right now. The loops are, however, separated in height. I do have high hopes for it’s performance the upcoming MW-season. But, just like all other antenna systems – this one demands real life usage in order to prove it’s useability. In any case, I’ll keep you posted about the assembly process. Just wish them horses to leave the spot where I’m planning to erect this “thingy”.



About Hans

Male. 50 years young. DX:er since 1980. In September 2011 I moved up to Vardø on Vardøya Island (EU-141) to start working as manager for the Coast Radio station in Vardø. I feel very lucky to have this opportunity to work with the thing that I think is the most interesting in the whole world - Radio! My main interest is, yeah - you guessed right: Radio. I'm a ham radio operator, holding the callsign LA2MOA. My main radio interests is low power operation and low band DXing on the amateur bands, but also mediumwave and tropical band DX-listening. I'm also interested in angling, fly-fishing and fly-tying. The area around Vardø offers some great opportunities to do all of this. And, since I'm of swedish origin, I'm also madly interested in ice-hockey and since 35 years I'm a hardcore supporter of Rögle BK in Ängelholm - one of the few really true hockey clubs left in Sweden.

Posted on 19. July 2012, in Antennas, QRM!. Bookmark the permalink. 4 Comments.

  1. dear Hans,

    for information, we designed the HDLA for Loops without any resitors. So the best results will be at ranges about 0 to 15 Ohms. The ideal Z-in is about 15 Ohm thats the best compromise for VLF & Shortwave.
    Inserting a resistor with around 1k you will be get some noise like a whip antenna. Check it out here in the city it is awful when i put a resistor in the loop . It may be the better phasing way to phase a active-Whip/ vertical against one of the loops to phase out noise.

    kind regards
    Dirk N , Germany

  2. Hi Dirk!

    Many thanks for this very useful information! Well, I have a bunch of terminating resistors here of different values all the way down to 5 Ohm’s, so I will experiment to see what I will find out. Maybe I’ll skip the terminating restistors completely. What do you think about increasing the loop circumference to about 24 meters, “squeesing” the loop so the upper apex is at about 3 meters and feeding the loop (i.e. connect the HDLA amplifier/matching unit) in the lower apex facing the desired listening direction?



  3. hi Hans,

    puh increasing up to 24m is a lot, i remember youve got 2 6er Versions so they are ideal around 6m circomfence….9 or 10m will be also no problem but be careful it could be that the signal levels rasising too high….i would prefer 12m circumfence. Remember it is a n active antenna. More circ. you can use for passive antennas (flags KAZ …)
    But try it to phase against a Vertical i think thats it.

    73 Dirk

    • Ok, Dirk! I will experiment a bit this month! Using smaller loops and phasing against a random lenth vertical sounds tempting. we’ll see what I come up with.

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