Wanting opinions on a base antenna!

'RAKER said:

Is it different from a 5/8 or just a common term for 5/8? I always thought a 5/8 was a very good antenna and yes, even magic at times, but that's really the atmosphere

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Short answer, you won't notice any difference.

5/8 is .625 wavelength. The .64 wavelength is about 6 inches longer at cb frequencies. An engineer (I can't remember his name offhand) calculated this length as the length that will get you the most gain before gain starts dropping off. The difference between a 5/8 and a .64 wavelengths is something like six inches.

Some people believe this length to be akkin to magic. Others take the smallest difference in perceived gain and treat it like its huge.

The thing is, the .64 wavelength being the maximum length doesn't take into account the matching system of the antenna. For example, the Maco v5/8 and v5000. With said matching system said antennas, which are shorter than even the actual 5/8 wavelength, is actually the longest length for said antennas before their gain starts to drop off. All 5/8 wavelength antennas have to be matched, and most of said matching systems will have some effect on the antenna's maximum overall physical length.


The DB

Getting cold outside in the mornings
I just went and measured an old maco a guy gave me for $2 at a yard sale because the ring got broke and 1 bottom arm got bent and its not even 20 feet long from the ring to the tip.
Now you got me a little perplexed because it sounded like you said a 64 was the highest gain and unless my calculators broke thats right about 23 feet so for highest gain how can a under 20 foot be the longest and a 23 foot also be the longest?

'RAKER said:

Now you got me a little perplexed because it sounded like you said a 64 was the highest gain and unless my calculators broke thats right about 23 feet so for highest gain how can a under 20 foot be the longest and a 23 foot also be the longest?

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I should have worded that better, my apologies.

When it comes to the Maco antenna specifically, we have to understand the difference between physical length and electrical length. To explain this I will use a mobile antenna as an example.

You have the full 1/4 wavelength mobile antennas, with no loading coil, and you have shorter antennas which all have loading coils (with very rare exception). The purpose of said loading coil is to electrically add length to make up for the mobile antenna's lack of physical length. So you are making that antenna appear electrically longer then it is physically, which in that case allows you to tune for SWR or resonance.

With the Maco we have the opposite problem, the matching system adds electrical length like a mobile antenna's loading coil, so to compensate for this additional electrical length, they shorten the antenna's length physically. It is the electrical length, not the physical length, that determines where the maximum antenna length is. In the case of the Maco the effect on gain is negligible compared to other 5/8 wavelength antennas even though it is physically shorter.

Also, I was referring to where the .64 wavelength came from, but I guess I should have been more specific. When the engineer calculated that length, he was assuming a ground mounted broadcast station with 120 radials of 1/2 wavelength each. It does not apply to other installations such as an elevated antenna with four 1/4 wavelength radials, and is in fact to long for said antennas. Essentially what happened is someone saw said report, took what sounded good and ignored the rest, then spread it around to try and sound knowledgeable. Unfortunately that happens a lot in the CB world.




The DB

Well that just seems stramge to me that a company would make an antenna physicaly shorter then what it could be because I would want the biggest tallest and highest I could make work tops over the rest
Reason I grabed that maco wasnt just the price but my cousin had one and he knows alot more then me about radios stuff but he changed it a month later to some other metal one cost him anbout $150 and says it works alot better. Also has 4 long bottom arms and some wire up the side bottom so I would think he wouldn't say that if it wernt true. I do know its 2-3 feet l;onger but don't recal the name. I'll ask him later

The DB said:

Also, I was referring to where the .64 wavelength came from, but I guess I should have been more specific. When the engineer calculated that length, he was assuming a ground mounted broadcast station with 120 radials of 1/2 wavelength each. It does not apply to other installations such as an elevated antenna with four 1/4 wavelength radials, and is in fact to long for said antennas. Essentially what happened is someone saw said report, took what sounded good and ignored the rest, then spread it around to try and sound knowledgeable. Unfortunately that happens a lot in the CB world.

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DB, I have a different recollection for how the .64 wavelength idea got started, but I have never been able to find it on the internet. I seem to remember the article was in a Radio or Ham related magazine of the time. It was long ago and I was in a ham radio distribution warehouse store front...at the magazine rack. I was reading an article that dated back <> to around the time of WW II. The article suggested that a couple of Japanese engineers discovered the idea that .64 wavelength was the maximum length that produced the maximum gain possible for a vertical monopole antenna. It was contradicting the idea that the .625 wavelength as the absolute maximum length.

Can you give me a link to the report you referenced?

'RAKER said:

Well that just seems stramge to me that a company would make an antenna physicaly shorter then what it could be because I would want the biggest tallest and highest I could make work tops over the rest
Reason I grabed that maco wasnt just the price but my cousin had one and he knows alot more then me about radios stuff but he changed it a month later to some other metal one cost him anbout $150 and says it works alot better. Also has 4 long bottom arms and some wire up the side bottom so I would think he wouldn't say that if it wernt true. I do know its 2-3 feet l;onger but don't recal the name. I'll ask him later

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Raker, sounds like you might be describing a Super Penetrator 500.

Sounds right. I was thinking it was a name with the letter p

is there any called perpetrater? seem s like that was it but I dont remember

Penatrator 500 made by HyGain.

It's a 5\8 wave vertical antenna. One of the best antennas made in it's day.

ok so that probably wasnt it because the one he bought is still made

MFJ makes them now.

ok. well that might be it then. Im new on here and dont want to hog it plus i dont know enuogh to so i'll go back to readring and learning

That's what this forum is about. If you have questions ask. This site has a lot of knowledgeable individuals.

What RT431 said. For the record I’m not one of those knowledgeable individuals

"RAKER , Welcome to the forum . Like the rest said , Ask Away ! 73 & God Bless , Leo