wolf radio antennas

[Master Chief]

Reason being is that old mother Earth is different from place to place and in some cases it really makes a big difference. And any test covers only this one place on the earth. So how would you deal with this factor?

We are not testing ground conductivity, we are testing antennas on an equal playing field. Would the same antennas perform better over sea water? Sure! So taking the ground out of the equation, we can concentrate on the performance of the antenna!

 

[Marconi]

OK guys, you're on. I think the soil conductivity in that area is typically very poor, so I will only have to bring my little old modified Starduster and a conventional homemade 1/4 wave ground plane, and send most of you guys packing and give the rest a real run for your money with them big old long antennas.

It will really be a ton of fun if accommodations can be had nearby. Will we have to bring our own support system or will every body use the same support structures?

 

[Master Chief]

See other thread about testing. This one has strayed a bit too much.

 

[WolfRadio.com]

Ed,
Where you talk about the base loading, is that in fact a loading coil, or just an impedance matching coil?

Doc,
That’s a good point, in the case of the tapped coil like the V5/8 and Jays I10K, I think your right – it is more of impedance matching device. However on a Sigma 5/8 old design, it’s just an inductor in series with the connection to the element – isn’t that base loading?

Ed, when the Sigma IV was tested, do you know what were the parameters, and outcome of the test in dB gain / ?-reference?

No, I never saw any of the original Avanti paper work for that antenna.

That was some list of antennas you gave, it would be interesting to see them all plotted on a gain scale.

I would bring my 7/8 avanti hybrid? and a ham international bigmac, they both beat my sigma4 and every other vertical monopole I ever tested over longer distance.

Bob, I would like to learn more about those antennas…..

Are you guys really gun’na have a ground plane shoot out in the middle of the desert??LOL

Wolf

 

[W5LZ]

Ed,
If it's an inductor at the bottom of the antenna as you say, then yep, I'd call it base loaded.
- 'Doc

 

[Master Chief]

I wouldn't call it an inductor. An inductor is a coil of wire that creates a magnetic field. With the Avanti Sigma 5/8, the loop is used to take the antenna to the next physical 1/4 wave in order to allow the feedpoint to work with a 50 ohm feedline.

Th Sigma 5/8 is a full size antenna and not loaded at all.

It makes up the missing 1/8 wave. 6/8 - 5/8 = 1/8

 

[Marconi]

What does the base of this old Sigma 5/8 look like? Can you see anything of the matcher? Seems that I recall that they had a weak physical connection in this area, near the feeder or coil, and wasn't this weakness a famous characteristic for this antenna? Anybody have any good pictures. The little picture I have of it in the Avanti PDLII assembly instructions, notes it as the AV170 and it appears very much to look like the current day Maco V5/8. It may also have had GPK radial tips that looked like those that go on the Moonraker as well.

 

[Master Chief]

I'll take some pictures of the 2 different Sigma 5/8 antennas and post them tomorrow.

The Sigma is nothing like the Maco. The Maco taps the coil and the "loop" on the Sigma is untapped.

 

[Marconi]

So the coil looks like Eddies inductors on his .64?

Wolf Radio's .64

 

[W5LZ]

Master Chief,
A coil is an inductor. It does produce a magnetic field. The interaction of that field with the field produced by the 'rest' of the antenna makes the whole thing seem longer than it actually is. And that means it's a 'loading coil'. The coil's position in the antenna determines what it's called, base loading, center loading, or top loading, type coil.
If the coil (or part of that coil) is connected between the feed point of the antenna and ground it's not a loading coil anymore, it's an impedance matching coil (at least that part between feed point and ground). Still produces a field, just reacts with things in a different manner.
Mostly a matter of definition of terms I guess...
- 'Doc

 

[buckwhite]

could the p50 be made to handle more than 1kw? i need more info on this. i have a neat project coming up and need a half wave antenna capable of handling 5kw with no radials. thanks, Bryan

 

[WolfRadio.com]

A coil is an inductor. It does produce a magnetic field. The interaction of that field with the field produced by the 'rest' of the antenna makes the whole thing seem longer than it actually is. And that means it's a 'loading coil'. The coil's position in the antenna determines what it's called, base loading, center loading, or top loading, type coil.
If the coil (or part of that coil) is connected between the feed point of the antenna and ground it's not a loading coil anymore, it's an impedance matching coil (at least that part between feed point and ground). Still produces a field, just reacts with things in a different manner.
Mostly a matter of definition of terms I guess...
- 'Doc

I couldn’t have said it better myself.

…in the case of the tapped coil like the V5/8 and Jays I10K, I think your right – it is more of impedance matching device. However on a Sigma 5/8 old design, it’s just an inductor in series with the connection to the element….

The Sigma is nothing like the Maco. The Maco taps the coil and the "loop" on the Sigma is untapped.

Chief,
This is correct sir…. However, what you call a “loop” is a coil, is a inductor.

BUT

The Sigma 5/8 is a full size antenna and not loaded at all.
It makes up the missing 1/8 wave. 6/8 - 5/8 = 1/8

As we know 5/8 of a wave does not self resonate on 27mHz, that coil at the bottom just happens to be close to a 1/8 wave (65 inches) long and is needed to cancel the capacitive reactance in that length element. It behaves the same as in the P-64 only mine are located up high. A ¾ wave antenna can be end fed without coils. I know for sure because I have made one, however, without phasing its main lobe has to high a take off angle for local work (30+ degrees). Talks good skip though.
On the same note, the P-64 is as long, or longer, than the Sigma, but I had to use 100 inches of coil (64” in the bottom and 36” on top) to cancel the reactance. I believe this is due to the location of the coils, the lower, or closer to the feed point they are, the less the inductance required. This is the case in mobile antennas as well.

What does the base of this old Sigma 5/8 look like? Can you see anything of the matcher?
So the coil looks like Eddies inductors on his .64?

That’s right…. Mine look just like the Sigma. Where do you think I got the idea???!
And you are right about the radials on the Sigma, they have the steel stingers.

could the p50 be made to handle more than 1kw? i need more info on this. i have a neat project coming up and need a half wave antenna capable of handling 5kw with no radials. thanks, Bryan

Yes it can…..

Wolf

 

[Master Chief]

This is good stuff to be sure! I concur the loop IS a coil. I wasn't able to express myself clearly enough that it's not a loading coil in the practical sence as the Sigma is not a loaded 5/8, but a full size 5/8. As I read this, I'm still not sure I'm being clear enough. The Wilson 1000 is a loaded 1/4 wave; the Sigma is not a loaded 5/8.

Here is what one of Avanti's engineers wrote me years ago. I asked questions about the Sigma 5/8, the use of stainless steel stingers, and the Sigma IV:

Hi Master Chief,
While I am no longer sure of the model #'s- if the Sigma 2 is the Sigma 5/8 vertical then the loop at the base is necessary to bring a 5/8 into resonance as a 3/4 wave. Because the loop is horizontal, it does not contribute to the vertical pattern. As you may know a 3/4 wave vertical has less gain than a 5/8- thus the
importance of making sure the loop (inducatnce) does not contribute to the vertical pattern. All 5/8 antennas use some sort of matching to achieve resonance and 50 Ohms. The loop is nice because of its mechanical integrity.

Stainless steel is an excellent choice for the tips because again it is strong for its diameter. The impedance near the end of an antenna is very high, so the fact that it is steel makes absolutely no difference. We even did some prototypes using graphite- very light weight and even though its conductivity is well above copper, there is absolutely no difference in efficiency- again because it is located at a voltage loop.

The Sigma IV must have been the antenna that looked like an ice cream cone. Although the antenna is 3/4 wave tall- the bottom quarter does not radiate. It serves as a matching section between the hi end impedance of the half wave radiator and zero ohms at the base. The feed then is tapped up to the 50 Ohm point and the gamma cancels the inductive reactance of the tapping rod. This antenna is electrically equivalent to the popular J poles so commonly seen on VHF/UHF.

I have often thought of writing the history of the company- believe me it is unique. Because we were family owned= things were done a bit differently than in a publicly owned corp.

Say hi to Howard- great guy.
73

He was refering to Howard Van Valzah, WB9IPG. Maybe some of you will remember him.

 

[Marconi]

You know MC that is a very interesting anecdotal story you have given us. You are a lucky man to have had such contacts in your life and with such visionaries from our past. I have said this before. Those guys that made Advanti work were just plain geniuses. It was as though they could see those abstract concepts in their minds eye, concepts that they eventually made so clear as to then be able to make them into real products that are still considered relevant today.

 

[WolfRadio.com]

I agree with Marconi that is a cool story. What’s better is he’s agreeing with what I said. He talks about the coils inductance and matching to ¾ wave. He does not mention loading per se but calls it matching instead. But make no mistake that is considered to be loading, and in this case base loading. If the coil were located in the middle it would be center loading.

Here’s more help: Radio Shack 1974-75 Dictionary of Electronics pg. 327 – loaded antenna – An antenna to which extra inductance or capacitance has been added to change its electrical (but not physical) length. (End def.)

Additional inductance or capacitance regardless of where it’s located on the element is considered loading. There’s really nothing strange about it Chief, it’s probably that you just never thought of it that way before, for whatever reason. Oh, by the way, excellent pics on Sigma. One last thing, if you look back a few pages on this thread you will find a post where I compared the Sigma IV to a J-Pole, also. Peace

Wolf