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Merlin Base Up Close and Personal

Well done test!

It does look nice up there.

Have you any way to borrow & test another antenna, such as a Sigma5/8, Maco V5/8, Penetrator, .64, I-10K etc.?

Sure would be cool if someone was able to send you an I-10K for testing and possible purchase.

Nice report, well posted.

What were you using for a rig / antenna / amp in the mobile?

Regarding the Maco V5000, I haven't had one of the 5000s, only the 5/8 but have been told that the only change was the wire gauge from the connector to the ring.

Anyone know if that's true?

And the Maco is quite lightweight when it comes to build material. I believe just the radials from a Penetrator weigh close to what the entire Maco V5/8 weighs.
You just might want to find a good used Penetrator, Sigma5/8 or a new/used I-10K instead, especially if you tend to encounter high winds in your area.

Also, a true 23' .64 (not the 20' Maco) would raise your maximum current peak to about 14' above that one, which I'm sure would improve your local performance, and DX as well I'll bet.

73
 
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linearone said:
how well did the antenna tune out?
Click to expand...

1.1:1 on channel 1

1.2:1 on channel 19

1.5.1 on channel 40

Funny thing about this is the SWR was higher on 1 than on 40 when initially tuned. Then changed to being higher on 40 instead of 1 after antenna was raised up to full height.

The only thing that I can think of that is different is when I tuned the antenna the mast was not bolted to the pole, it was just resting in it.

There may also be the possiblilty that I transposed the numbers on the first reading.

Antenna will be retuned in a few weeks. Tower is going up to take place of pushup pole.
CDX-007 said:
Have you any way to borrow & test another antenna, such as a Sigma5/8, Maco V5/8, Penetrator, .64, I-10K etc.?
Click to expand...

I have not tested any other antenna in a controlled setting to be able to accurately and honestly compare any results. However in the very near future I will be comparing a Maco V 5/8 under the same control settings as well as a an A99 with and without a ground plane kit.
CDX-007 said:
What were you using for a rig / antenna / amp in the mobile?
Click to expand...

Mobile was a 98 GMC with a Wilson 1000 roof mount, 2x4 Class C amplifier and a Uniden 68.
 
I don't agree on a top had or coil at all for any antenna, unless you "have" to shorten the antenna, and/or it's needed to bring the antennas impedance down to 50 ohms. In reality, the most efficient antenna are ones with "no" extra components. Adding components are used to help "shortened" antennas operate almost as well as a full sized 1/4 wave antenna, while trying to add the least amount of loss as possible.. But why shorten and/or add these losses at all? Worse of all, why add these losses on a quarter wave!

Perhaps Jay with his Predator 10K would take his off as well, and make a true .64 straight antenna/radiator.. A capacity hat makes sense on the Ham bands, where you must shorten the antenna significantly, but for a quarter wave 27mhz antenna, this literally makes no sense.

Many don't get this fact, as W5LZ pointed out, a better antenna is one with no added inductors, capacitors, and/or top hats at all.. Yes top loading and/or a capacity hat may be better than a bottom fed coil because it adds lower losses if you "Must" shorten the antenna! However, the better solution is not to shorten the antenna at all, and not add this unnecessary losses. Generally a quarter wave doesn't need any components at all, as if the radials/ground plane kit is adequate, a flat SWR isn't a problem. The antenna would also be much more stealthy, by making it another foot or two taller, and getting rid of any extra crap on top.

A .64 or 5/8th wave needs an inductor to tune it. The antenna has capactive reactance that needs to be canceled out, and the coil adds to the antenna electrically, and once you get up to a 3/4th wave, the antenna's impedance is near 50-70 ohms. A 3/4th wave antenna just as a 1/4 wave needs not coil or capacity hat at all.

A end fed 1/2 wave antenna is actually more difficult to tune than either a 1/4 wave, 3/4 wave, and/or a half-wave, as it's impedance is well over 1000 ohms! You generally have to use both capacitor and inductor lump components at the antennas feed point, or a very efficieint impedance matching transformer.
 
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Use the 55 for awhile and you may learn to love it Cajun. Sounds like its doing a good job. And all meters are different. I do like the 10Ks but never used one.
 
Finally figured out what this mess is on the Merlin. It's where a tap broke off in the hub. :thumbdown:
33bihsn.jpg
 
from the builder...

The reason the top radials are not welded all the way around is to provide a stress/strain relief, it is not because of poor craftsmanship, he had one crack in a prototype and since he has changed to the partial weld there has been no issues

as far as the holes lining up, put it on one of the other two radial stubs, i bet it lines up
 
chale said:
from the builder...

The reason the top radials are not welded all the way around is to provide a stress/strain relief, it is not because of poor craftsmanship, he had one crack in a prototype and since he has changed to the partial weld there has been no issues

as far as the holes lining up, put it on one of the other two radial stubs, i bet it lines up
Click to expand...



I own a machine shop, an that is some of the worst work I have ever seen.

The radial holes should line up no matter which one they are put on, unless they were drilled with a hand drill and tape measure or something similar.

I also don't buy that deal about stress relief either.


Ronnie-The Toolman
 
moleculo said:
I'd like to know how tall that antenna is when you get it assembled. I'm betting that it's shorter than similar antennas because of that cap hat design. His manual is kind've funny.

OK, I just figured it out: "The feedpoint is 75 inches from the top of the antenna". That, with the radials sloping down and the lack of matching network tells us that this is a 1/4 wave groundplane radial antenna. The coil and cap hat account for the missing length. and the angle of the radials is what brings the impedance to 50 ohms. I wouldn't expect miracles from this antenna, but if it does what you need it to do, then you'll be happy.
Click to expand...

That has been my point in another discussion that I won't link to, but fans of this antenna are claiming some things that just can't be backed up. And the manual is funny-- what's that about everything being in phase so it won't distort the sine wave?

But you know, if people want to buy this antenna, then buy one. Hell, buy two, it won't affect me.

Rick
 
- Yep, the more of these 55s & A99s, Top Ones, Stardusters, etc. there are out there, the better the performance of my Penetrator .64 shines.
 

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