20-176 vs ocf dipole for 155mhz / 453mhz?

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psdavidson

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20-176 vs ocf dipole for 155mhz / 453mhz which would you recommend?
I built the dipole but its at another location 3hrs away and does fine there.
I have the 20-176 I just picked up for a good price at this house and I want to put an antenna on the house. because of weather conditions and the steep pitch I just want to this once right now. so do I build another dipole and mount it or mount the 20_176. which would be the best performer.
most every thing I want to listen to is around the 155mhz/453mhz area.

thank you
 

LIScanner101

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The results of the OCFD are, from my limited understanding of them, highly unpredictable. It's more of a "try it, it's cheap, whaddya got ta lose" kinda thing. With that said, it may be hard to predict how well it would do until you try it.

WRT the OCFD dipole you made - can I assume it's the regular 18"/48" dimensions?
 

br0adband

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As noted in other threads, the wire version of the OCFD is easier to construct (basically two pieces of wire and the matching transformer and you're done) and offers very similar performance to the full blown copper pipe version of the same design. Make a wire version of the OCFD first and see how the performance is; if it's as good as you'd hoped, then the full blown copper pipe version should offer similar or slightly better performance. If it's not as good well, there's your answer and it was achieved with much less effort, money, and time spent on constructing it.

I have a wire version and I built a copper pipe version last week to match it and so far it "works" but not nearly as well as I'd hoped, but that's just my specific experience for reception in my specific area, etc. I built a 1/4 wave ground plane and using just a 150 MHz element at 19.7 inches long (with the ground plane elements, 4 of them, at 20") and it cost me a buck-fifty for the SO-239 chassis mount (the elements are made from old wire coat hangers) and so far that antenna performs better across the entire 110 MHz to 940 MHz spectrum than the OCFD does - but again, that's my specific experience and so on.

Experimentation with antennas is the only way you'll find what works best for you in your given situation, and luckily they're pretty cheap to construct, especially if you already have the necessary parts (coat hangers, wire, etc).

And just for the record, I bought one of those Radio Shack 20-176 antennas a few weeks ago (never owned one before, oddly enough) and in the exact same position as my homebrew 1/4 wave ground plane made from that chassis mount and coat hangers, the Radio Shack antenna was somewhat useless by comparison. On strong signals like control channels in the 150 MHz and 450 MHz ranges, my homebrew was 5x more receptive as measured by signal strength, go figure. ;)
 

nanZor

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And just for the record, I bought one of those Radio Shack 20-176 antennas a few weeks ago (never owned one before, oddly enough)
If used, doublecheck with a multimeter that you actually have continuity from the center pin to the main vertical antenna element. I've seen those feedpoints get pulled apart from not securing the feedline to the mast properly.

If you are using an S0-239 to F adapter, also be sure to check for continuity from the end of your RG-6 to the main element.

Just hearing signals, even if weak, may mean that you may not actually have physical continuity, but a weak capacitive coupling! I found this out the hard way a long time ago when an old NMO mount antenna seemed to be working poorly, but not bad enough to be absolutely dead. The radio just croaked on transmit, yet I could still hear stuff! I had no physical continuity and had to use a thinner body o-ring seal. Just an example for thought....

OH, and on 150 and 450mhz, the 20-176 should smoke the ocfd especially on uhf as it is primarily an amateur vhf/uhf dual bander. Then again, at the price point of an ocfd, I say try it and see.
 
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