Workman W58 Not Really A 5/8 Wave Antenna?

[SuperLid]

I just recently purchased this antenna, I built it per the supplied manual, the Maco V58 corrected manual and using all of the information I found on its construction out there on the web I can find. It just does not work for me as advertised.

I tested the antenna at three heights above ground, 6.5', 16.5' and 22'. I have tried two different lengths of coax, the VNA launch cable all with the same results. The antenna center frequency as built, is between 22-23 MHz.

The Workman manual states, the radiator length starting point at 240, the Maco is 248". I set the bracket that is clamped to the radiator to a point that allows one inch of vertical clearance between the tuning ring ends.

I have tried the Master Chief instructions, as well as doing the math. Nothing adds up....to a 5/8.

The way I interpret the antenna, is the ring is a 1 turn inductor, tapped 6.25" from the center connection point of the two halves. This makes the lumped loading side of the inductor 24", the tap wander lead is 9.5" and the angle bracket is 7", for a total of 40.5". The shunt side of the inductor is 11.5" at the suggested starting point.

The math suggests, this should work at 248" in total length (less the base tube at 12", fr a total radiator of 236
") but it doesn't. So, I am thinking the ring match is not working as intended and is being cancelled. The only way I can find a match at 27 MHz, is at around 16', or actually slightly less. This leads me to believe that this antenna is a 1/2 wavelength antenna. To get to 5/8 wavelength, one would need to increase the length.

This antenna has been built by others that experience the same results that I have. The manufacturer has not been helpful. Maco says this antenna is a copy of theirs, that has some build problem and does not work. I have read quite a bit about the Maco, but the Workman info is sparse. I am looking for some real world experience that may shed some light on this, as I have wasted 4 days doing this and that to make this thing work on 27 MHz as a 5/8 wave, to no avail.

Thanks,

SL

 

[Jay Mojave]

HELLO SL; Maco probably will not help out with a copy of there antennas design, makes sense.

Those matching rings change two values of inductance and one value of capacitance. At one time in adjustment. Not user friendly even with the proper antenna length. Wish I had the majic fix but I dont. You just have work with it with the antenna analyzer. Making antenna and matching ring length measurements and what frequency its on, and with time you will probably fix it. Then post results.

Jay in the Great Mojave Desert

 

[SuperLid]

Maco says the problem is with the base tube assembly of the Workman and if I buy theirs, as it is sold as a spare part, the antenna will work as designed. I find this hard to believe. There is no magic in the base tube. It is 12" of pipe, with an insulator at the top, with 3.5" of radiator inside the base tube.

3 days of fiddling with this and that has proven one thing and one thing only. This is a half wave antenna, not a 5/8 wave as advertised.

If someone knows more than I do, please enlighten me, as I am quite frustrated with it as built.

Thanks,

SL

 

[TheBlaster]

Just a quick thought you are tuning/checking with the 4 radials attached ? Radials have a tendency to detune the element as far as matching. Lowering frequency of resonance.

I make a 5/8 for 27.205 to be about 257 inches long... so 248 inches is not far off as a starting point.

300/27.2 x 0.625 = 6.89m x 0.95(VF) = 6.54m = 257 inches

What is the SWR when TX on CB freqs ?

22-23 MHz on an analyzer sounds like it may be seeing a 1/2 wave at that frequency (though it does not make much sense as the matching system would probably not be enough to get a match as a 1/2 wave that low) If I recall a close to 50 Ohm 5/8 at freq should be reactive and something between 75 and 425 Ohms. A half wave more like 2-3k Ohms.

Double check all contacts are showing continuity, sections, radials and matching sections as well with a multimeter. Good luck.

 

[SuperLid]

Hi Blaster,

Yes, the radials are installed, as they should be. The 248", is from the Maco manual. It is measured from the bottom of the base tube, which is 12". That would leave 236", plus the loading from the coil bracket, coil and wander lead tap.

I wasted another day on this antenna. The antenna does not work as a 5/8 wave antenna. The match I found is at a total length of 179", less the base tube is 167" of radiator. Add the coil to radiator bracket of 7", the coil that ended up being 18.5" at 50 ohms and the wander lead tap of 9". Total electrical length of 201.5" or thereabouts. This puts it somewhere between a 3/8 wave and 1/2 wave, not 5/8.

I see you have also included VF. VF of what?

I have been over this antenna 100 times, tweaking this and that for a week. I don't think there is much more I can do to polish this turd.

Thanks,

SL

 

[wjm1129]

I think a 5/8 antenna total length should be about 22.5 feet. Sounds like your antenna is too short.

 

[TheBlaster]

I use a VF of 0.95 when making insulated wire antennas.

 

[SuperLid]

I see, this is not a wire antenna though. Your formula is close enough to 585/f in the real world anyway.

Thank You,

SuperLid

 

[SuperLid]

I think a 5/8 antenna total length should be about 22.5 feet. Sounds like your antenna is too short.

Yes, if there is no loading, which in this case, there is.

 

[Jay Mojave]

Ok I reread the posts here. The base unit on the Maco have some Capacitance that is figured into the matching for the V58. Which maybe different for you copy antenna. Need to measure that.

Jay in the Great Mojave Desert

 

[SuperLid]

I looked at the network analyzer measurements and dealt with the reactance by adding C. I also increased the electrical length, which then achieved a match at 27.2 MHz.

Not at all what it is purported to be out of the box.

I am giving it to a friend, with a new run of RG-8/U and hope I never see it again.

I bought two, one for him and myself. I am going to take the unused one and make some tomato poles out of it.

73,

SuperLid

 

[Jay Mojave]

Yo SuperLid: So what was the added capacitance value added and were, and what was the antenna length. Inquiring distinguished super CB'er wants to know.

Jay in the Great Mojave Desert

 

[Dr_DX]

I looked at the network analyzer measurements and dealt with the reactance by adding C. I also increased the electrical length, which then achieved a match at 27.2 MHz.

Not at all what it is purported to be out of the box.

I am giving it to a friend, with a new run of RG-8/U and hope I never see it again.

I bought two, one for him and myself. I am going to take the unused one and make some tomato poles out of it.

73,

SuperLid

So not to poke a dead horse, but a couple of suggestions.

1. Make sure your feedline is tuned to 27.2 (or whatever freq. is your target freq.). This is easily done with your network analyzer.

2. I have found that on the Workman, I have better success with reversing the direction of the ring.

3. Make sure to adjust the bottom joint, not the top one. The larger diameter will give you a broader SWR band.
.

 

[SuperLid]

So not to poke a dead horse, but a couple of suggestions.

1. Make sure your feedline is tuned to 27.2 (or whatever freq. is your target freq.). This is easily done with your network analyzer.

2. I have found that on the Workman, I have better success with reversing the direction of the ring.

3. Make sure to adjust the bottom joint, not the top one. The larger diameter will give you a broader SWR band.
.

1: The feedline was a normalized launch cable from the network analyzer to the feedpoint. I should not need to add the inherent C of the coax to the circuit, if the antenna is designed correctly (which it is not).

2: Reversing the ring changes nothing electrically, if the tap point moves from one side of the tuning ring to the other, in respect to the feedpoint.

3: Adjusting the match, from the bottom versus the top, will make the radiator shorter at the bottom, which will make the antenna narrower bandwidth, not wider. This is not relevant, as I used the 6" of overlap as per the manual, as well as all of the other recommended overlap dimensions. At the end of this exercise of debunking snake oil marketing, the antenna is too short to be a 5/8 wave antenna at 27 MHz.

The antenna is inductive at 27 MHz. It's not a 5/8 wave 27 MHz antenna. It starts out life as built per the manual, as a 3/8 wave at 23.5 MHz.

Thanks,

SuperLid

 

[Dr_DX]

1: The feedline was a normalized launch cable from the network analyzer to the feedpoint. I should not need to add the inherent C of the coax to the circuit, if the antenna is designed correctly (which it is not).

2: Reversing the ring changes nothing electrically, if the tap point moves from one side of the tuning ring to the other, in respect to the feedpoint.

3: Adjusting the match, from the bottom versus the top, will make the radiator shorter at the bottom, which will make the antenna narrower bandwidth, not wider. This is not relevant, as I used the 6" of overlap as per the manual, as well as all of the other recommended overlap dimensions. At the end of this exercise of debunking snake oil marketing, the antenna is too short to be a 5/8 wave antenna at 27 MHz.

The antenna is inductive at 27 MHz. It's not a 5/8 wave 27 MHz antenna. It starts out life as built per the manual, as a 3/8 wave at 23.5 MHz.

Thanks,

SuperLid

1. Only if the antenna is purely resistive - which it is not.
2. Just my experience as said, YMMV.
3. You said the antenna was too short for 5/8 @ 27Mhz. Why would you be making the radiator shorter? You will be making it longer, which does increase the bandwidth. Which is also how the manual says to adjust the vertical radiator.

Maybe there is a fault in the construction of the antenna.

You said you have 2 of them. Try the other one and see if you get the same results. Worse case, you lose a little time and have some expensive tomato poles. Best case, you get the antenna to tune.

Many members here have setup and used the Maco/Workman 5/8 antenna and have been able to get it to tune quite well @ 27MHz. It may not be a true 5/8, but you should be able to get it to tune.

IMHO, the closest that you will get to a true 5/8 is a Hygain Super Penetrator or for a little more, a Colossal 10K or an I-10K if you can find one.

Good Luck.