I hope someone can help me on this...
I would like to try a LPDA , this would be for Tx on 10,11,12m.
Coax feed, 50 ohms.
Thank you. 73
I would like to try a LPDA , this would be for Tx on 10,11,12m.
Coax feed, 50 ohms.
Thank you. 73
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Help, Info on LPDA for 10-11-12 meters.(Log-Periodic Dipole Array)
- Thread starter Mudduckmobile
- Start date
imax 2000 or antron 99 will sure cover all those bands.
Starduster may go as low as 24 MHz, gain master may also.
BUT they are not wires.
Make a fan dipole, center feed cut for 12 meters on top, 11 meters in middle and 10 meters on bottom
Starduster may go as low as 24 MHz, gain master may also.
BUT they are not wires.
Make a fan dipole, center feed cut for 12 meters on top, 11 meters in middle and 10 meters on bottom
Thanks for your input, I dont want to use an omnidirectional antenna, (imax, a99 etc), I want to try an "simi-directional", directional antenna for my field DX work, The PLDA antenna has most all of the requirements for my task, and from what I have read I should get away with putting it together with pvc, to telescope the elements, boom, with my mast 35 ft. fiber glass/pvc. and I will use 14g wire for the elements run on the outside of the pcv. I just need modeling help so I can get the right measurements for the wire tipe/element size.
I have used 2 and 3 element beams in the field, and it was fun, I have ran a A-99 in field too, and right now am running a "starduster clone" I built from S>S rods. in the field.
I was thinking SKYPPER, and then got to thinking about the PLDA, and a PLDA is the plain.
Depends on how many elements you want the antenna to have. A typical LPDA (not PLDA) covers a range of frequencies such as 7-20 MHz continuously. You'd be looking at 24-30 MHz, roughly. You have to figure out just how many elements you need. Google and Norton searches have lots of information on construction and calculating. I'd suggest you study a bit on the subject and get an idea of how big an LPDA can be.
I typo'ed, I might be wrong but I was thinking that I would need 6 elements? but I could be wrong. and I know it will be big if it comes to light...I was thinking to make it in 1/4 wave to help with the size...
Whenever I see this I think the poster is in need of some antenna theory. Firstly the syntax is wrong as you cannot make an antenna IN a 1/4 wave...whatever that means. I assume you mean make it half-sized? If that is the case then it will be all wrong but will operate nicely over the six meter band at 50 MHz. If you mean make it out of 1/4 end fed wave elements then it is not an LPDA of any kind. I suggest you look at some LPDA designs to see what they are really made like. They require a split boom to start with with each element half transposed by being connected to the different boom pieces alternating dowm the boom length. Take a look at the Tennedyne T7 with has an 18 foot boom and seven elements. It operates over the 18-32 MHz range.
http://www.tennadyne.com/
The big problem with LPDA antennas is that they have low gain for the number of elements, are generally quite large and have a large turning radius. The ONLY advantage they offer is wide bandwidth but it comes at the cost of low gain mainly.
Thank you for the link, and I'M trying to get around this antenna, makes my mind work and ask questions, so yes I'm learning and that's the fun part. Thank you for your help!
....good link I see the T6 has a 12ft boom and would work too. more reading to do, so back to the link. thank's!
Check out the various links in this Google search. More info than you will ever need.
https://www.google.ca/?gws_rd=ssl#q=LPDA+design
https://www.google.ca/?gws_rd=ssl#q=LPDA+design
The LPDA calculator at changpuak.ch/electronics/lpda.php
is very nice. I have come up with a boom of 169.11in.
4 element 24-30mhz unit with widest ele. #1 at 123.03 in. more to read and learn.
Thank you for your help! 73
is very nice. I have come up with a boom of 169.11in.
4 element 24-30mhz unit with widest ele. #1 at 123.03 in. more to read and learn.
Thank you for your help! 73
Now the stroobandt.com site has me up in arms...
, I'll get this, it wont take over night but i'll get it. thank you .
, I'll get this, it wont take over night but i'll get it. thank you .
Glad to se there is still some home brew happening
But the effort may not be worth the results.
the small LPDA you are looking to build will have about as much gain as the simple fan dipole, and about as much rejection.
For field day purposes two fan dipoles strung up short quick and easy, 50 ohm impedance match and on the air quick making contacts.
either way have fun and good luck
But the effort may not be worth the results.
the small LPDA you are looking to build will have about as much gain as the simple fan dipole, and about as much rejection.
For field day purposes two fan dipoles strung up short quick and easy, 50 ohm impedance match and on the air quick making contacts.
either way have fun and good luck
Thank you, thank you all for your input. I'll tell you I have spent about 6 hours today, and about 4 last night...And I must say, It's just not to be. The Fan Dipole I looked at, can see it being quite nice. I had something I wanted to do, and it's just not to be. So...I think I'm going to go with a "Bird-Yagi", at least it's on the top of my new list.Glad to se there is still some home brew happening
But the effort may not be worth the results.
the small LPDA you are looking to build will have about as much gain as the simple fan dipole, and about as much rejection.
For field day purposes two fan dipoles strung up short quick and easy, 50 ohm impedance match and on the air quick making contacts.
either way have fun and good luck
Thanks to everyone for your input, and I'm off to looking around the web some more for ideas to put on my list.
73
- No one is chatting at the moment.