Log Periodic Dipole Array(LPDA)

[TeRayCodA]

Anyone using one?

How do you like it?

I'm thinking of building one from some plans I found in an antenna book I have,that details how to build one for 225-400Mhz,& plans for other bands also.

I know they are directional,but how well do they receive from sides? Do they perform well for Mil-aircraft?

 

[kb2vxa]

Hi T and all,

It all comes down to compromise between gain/directivity vs. bandwidth as in any beam antenna. The log is the greatest compromise of all sacrificing gain and directivity for increased bandwidth. The rule is that gain/directivity is on one end of the scale and bandwidth on the other.

It appears that you may be using the wrong term, what you describe is a dual band antenna, two beams on the same boom. I have seen several makes, usually for 2M-70cM operation and one tri-bander for 144, 223 and 430MHz.

When you get down to it, the HF "logs" for Amateur Radio aren't logs at all, they're actually two or three elements for each band on the same boom. I have seen but one true log for VHF/UHF that receives everything from 6M to 1.2GHz. and has rather little gain on any given band true to the log periodic design. There is another thing to consider, I have seen TV antennas of the V-log design (self explanitory) that will cover FM broadcast, ham, public service and commercial bands as well because they fall within the TV spectrum.

Then there is the WA1HLR Dog Log 80M mobile antenna but that's another story. (;->)

 

[TeRayCodA]

It appears that you may be using the wrong term, what you describe is a dual band antenna, two beams on the same boom. I have seen several makes, usually for 2M-70cM operation and one tri-bander for 144, 223 and 430MHz.

No,I don't think I'm using the wrong term, is this not a log periodic dipole?

http://eje.railfan.net/dpdp/

 

[PluckyPleco]

No,I don't think I'm using the wrong term, is this not a log periodic dipole?

http://eje.railfan.net/dpdp/

Yes, that's a log periodic antenna.

Plec