Multiple wavelength antennas?

[breadtrk]

Back in my ground radio days, I learned some theory about the advantages of multiple wavelength antennas, Do those theories still apply at VHF and UHF?

Has anyone experimented with this?

 

[zz0468]

Yes, the theories still apply. I've heard of people using rhombics on 2 meters for moonbounce, for example.

 

[prcguy]

When you get more than a half wavelength for a single element the antenna may not radiate broadside to the element and this is a problem for a vertical antennas at VHF/UHF. Multiple wavelengths will give multiple lobes and this can be used to an advantage in the rhombic as mentioned above, otherwise you can create a big antenna with poor performance at the horizon, not to mention impedance matching challenges. Multiple wavelength antennas are mostly confined to HF bands where hams usually have antenna tuners and the antennas are horizontal.
prcguy
prcguy

 

[breadtrk]

Thanks! I am remembering some of it and I do seem to recall the the pattern changed quite a bit, depending on how many wavelengths you stretched out the wire.

BTW, prc, I'm almost done with the dipole array for 800 based on your thread. I'm building it so I can add the directors if needed.

I'm looking for some really good info about phasing harnesses and perhaps a calculator.

 

[N_Jay]

Hmm, just for fun, maybe a Rhombic at 2.4 GHz for WiFi? :twisted:

 

[kb2vxa]

Good old N_Jay proving once again the laws of physics, off the cuff remarks and my antiquated quoting style cannot change and Obama has no magical powers to change them. (;->)