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Hi. I just purchased a TH11 and a VB66DX. I am having lots of trouble
resonating the VB66 in the lower part of the 6 meter band. I have done all the measurements that the book called for, talked to the factory, changed baluns
from the supplied rg58au to rg213, rg6, rg13 and now back to rg213u.

This antenna does not look like one that KD4ESV, Samuel in Fla. has. His
must be made by Telex. His DE is longer and bigger diameter than mine
as well as his beta rod dia being much bigger. Samuel was kind enough to send digital pix of his.

Anyone have a fairly new one that has figured out what might be going on?
I have used the analyzer but the rig is just as accurate looking out and for that
matter better to me. I would most certainly appreciate any help so I can reload
these new antennas into the air. Thanks to all that might have info.
73 Wayland k4ws

Hello Wayland,

I downloaded the Instruction Manual for the Hy-Gain VB-66DX 6 Meter Beam Antenna and after skimming through the manual I noticed something very strange about the Driven Element and the Reflector lenghts. I've never seen a Driven Element LONGER than a Reflector Element used on any frequency band.

Hy-Gain's Part List in the manual indicates the following information:

# 175165 Reflector Element 7/16" D X 52" L QTY. 2

# 172802 Driven Element 7/16" D X 54 3/8" L QTY. 2

I think what we have here, is the Technical Writer for Hy-Gain did not Proof Read his documentation .... OOPS!

Just REVERSE the DRIVEN & REFLECTOR ELEMENT TUBING LENGHTS and I think you'll find the Beam Antenna will TUNE at the low end of 6 Meters.

73,

Dan
WA9WVX

Thanks for the info, Dan, but you were looking at the front director. It is longer
than the other directors which I have heard of over the years but is not the norm.

The reflector length in my manual is 2x 59 1/16 inches and the driven element
is 2x 55 7/8 inches. The problem I have is with the front director where you
caught as the reflector.

The older ones, as I stated from looking at digital pix from KD4ESV,
used bigger dia tubing. His driven element is 114 inches and reflector
118 inches compared to mine above of 111 3/4 inches and 118 1/8 inces.
So the reflectors are very similar length. I think the dia has changed the whole
scheme. His beta rod is 55 1/2 inches which is the same as mine but looks
much bigger in diameter. I am going to try to raise it a little higher and see what happens but I think nothing will. Every 6 meter ant I have checked in the clear 5 ft or so off ground when building and testing always had good swr wherever it said it was to have it. I thnk you are on the right culprits, though! hi

Again, thanks, Dan, and if you see anything else or know anyone that has the
MFJ company's Hy-Gain VB66DX, please ask them about their experiences.
73 and a good holiday to you, Dan. 73 Wayland k4ws

Hello Waylend,

I took the information directly from Hy-Gain's website and dowloaded their manual for VB-66DX Beam Antenna.

All of the elements are listed as follows:

# 172922 Director Elements, 7/16" D X 47" L QTY. 8

# 175165 Reflector Element, 7/16" D X 52" L QTY. 2

# 172802 Driven Element, 7/16" D X 54 3/8" L QTY. 2

# 175669 Beta Tube, 7/16" D X 56 1/2" L QTY. 1

You are trying to convince me that the Driven Element & Reflector Element are the correct lenghts. No, I don't think so because I had one of their Beams up 33 years ago and the Reflector was longer than the Driven Element. In fact, by antenna theory the Reflector is 5% longer than the Driven Element and the first Director is 5% shorter than the Driven Element.

The only antenna manufacture that had a longer End Director (Last Element) was built by TELREX (No Longer in Business) located out in New Jersey not the former TELEX Hy-Gain Product. Some how I believe you are confusing the two different companies.

As far as Tuning and/or Measuring VSWR or RF Forward / Reflected Power on all Beam type antennas, it is wise to raise the boom vertically, perhaps attaching the metal boom to a wooden structure to minimize any interaction between the Driven Element and the surrounding objects.

73,

Dan
WA9WVX

40+ Consecutive Years Licensed with the same Call Sign
37+ Years with a 1ST Class FCC Radiotelephone Operators License, now considered a GROL
34 Years in the Professional Land Mobile Two-Way Radio Business as a Design & Development Engineer

Hi again, Dan. I have the manual, the antenna, and have also downloaded it
before I purchased it. I have been a ham for 48 years continuosly. I wish
what you are "seeing" was my problem. I really mean that as I am frustrated
with it. The swr just is not coming into play like it is advertised as.

Dan, let me lay out the specs of the antenna in the manual that you downloaded. The reflector is a telescopic element on each side of the boom
(as all the directors are, too. ) The driven element is a single piece element
on each side of the boom. All measurements are taken from the center of the
boom to the end of each element. I made my adjustments at the low end of the
band as there were 3 choices on elements and beta bar. Look on page 5
figure 5 and you will see the correct measurements for each element as they say and as reflected below in the 50.1 (lowest setting range. So the nr'd
tubings you are seeing don't reflect the inner smaller tubing that goes inside
all elements except the driven element to extend them.

Reflector length all the way end to end= 118 1/8 inches or 2x 59 1/16"
Driven element " " = 111 3/4 inches or 2x 55 7/8"
Dir 1 = 105 inches or 2x 52 1/2"
Dir 2 = 102 1/4 inches or 2x 51 1/8"
Dir 3 = 102 1/4 inches ditto here
Dir 4 (front) = 104 inches ******* unusual but
m2 does this I understand 2x 52"
It appears they have "nulled" the effect of directors 2&3 with Dir 4.

Down load the manual, Dan, and see if you see something. The parts lists
tricks you. I have assembled it and it looked okay except I don't like the front
director longer than the others and will probably make it the same size as
2 &3 or 1/2" shorter at the worst. I think we have been on different "pages." hi

Keep looking as I really need some help on this matching problem. I agree that no reflector ever should be shorter than the driven element but that is not the case here. Thanks, Wayland k4ws

by the way, I replaced the rg58u with rg213 but tried others and used the velocity factor for each and made 1/2 wave balun which is what they made with the rg58u(junk).

Hello Wayiand,

I haven't forgotten this antenna issue as I've been studying the Hy-Gain manual. I've also been donig the 468 formula, over and over again. There are many descrepencies within the manual regarding element lenghts, esspecially using Hy-Gains Figure # 5! It's like the mysterious someone of Hy-Gains Technical Staff interpreted the most active portion of 6 Meters is 52~54 MHz .... NOT! The reason I have stated this is when you view their VSWR Chart Line # 3 for under a 2:1 frequency coverage, perhaps for the Austrailan Hams but not here in the United States!

I feel their Technical Support Staff need to bring this issoe to their Antenna Design & Development Engineers this is the BIG "IF" if they have any experience personnel that understand VHF frequency usage versus mode of operation.

I understand how frustrating this is for you and I don't rremember the 66DX antenna having telescuping elements, they were one piece elements when I had mine and you would slide each element into the boom bracket and tighten them down. I do remember the beam coming with RG-58/U but I didn't operate a KW at the time.

If I were sitting in your position, frustrated with MFJ / Hy-Gain's lack of support, I think I would call Texas Towers and order out 3 lenghts of 7/16" D x 12' L Cut into 6' L lenghts for shipping purposes. When the Tubing material arrived, cut each one for the proper lenght for the Driven, 1st Director and the Reflector Elements, Tune the Antenna for the lowest VSWR. Raise the antenna on to the mast pipe and call this a Bad Experience with MFJ / Hy-Gain Antenna Products!

73,

Dan
WA9WVX

Dan, I have walked the walk! hi
I had a friend that had tubing the size of the short 8 inch ones that are in all elements except the driven element. The tubings are around 5/8" and taper
and allow the 7/16 inch stuff you saw to slide in and telescope. I had another
machinist buddy adjust the ID difference and cut me 2 eight inch pieces of the
5/8 tubing my friend gave me. He then reamed the insulator out where the newly cut 8" stubs would slide into the driven element insulators. I now have
adjustable driven element halfs and have preset according to kd4esv's older
version said on the shorting bars and the driven element take off clamps for the balun and feedline.

It is cold as the dickens outside and snowing thus you know what the resulting
work had to end up looking like......with the exception of my nearly frostbitten
fingers and muddy shoes! hi

The swr now is starting to look like it should. There is no 2mhz wide 1.1:1
swr but I have .688mhz wide 1.1:1 in the lower end. I used Kd4esv's measurements on the shorting bars and the de wire clamps so I can probably
tweak it better as the 1.1:1 goes from 49.506 to 50.194mhz....but it is too cold
anymore today. Just wanted you to know that you are right-count my losses, redo the driven element and go on! Good luck to the future Hy-Gain buyers!
I will pass the info along to the "engineers" down there for what is is worth and how far it will actually go and to what extent it will change things!

;Again, Merry Christmas and I hope to have this whole antenna system, TH11
and VB66 flying next week sometime if lucky.

73, Wayland k4ws

Hello Waylend,

Your antenna project seems to be taking forever but it appears you're in the home stretch with your friends help. It's always nice to have good friends that can supply tubing and a machinist to modify the diameter to what is needed. Our electronic industry and other companies in general have fallen on hard times since most of manufacturing has been outsourced to foreign countries and the Quality has Tanked. All of the companies only worry about the bottom line but they lose customers faster than getting new ones.

We use to be # 1 in Quality & Manufacturing but the United States is now down to # 3 or # 4, which is not a Good position to be in. Between Corporate American Management and our U.S. Federal Government Elected Officials / Servants that represent the Americam Workers, we're headed down hill at a rapid pace and who knows how far this will go with the current economy and our place in the Global Markets. Just think when the last time you saw a TAG stating: Made in the U.S.A.

As far as working on antenna systems out in the Cold Weather, I've been there and done it several times over. I think it took a couple of hours to defrost my hands and it's been especially fun working at 50 to 100 feet on a tower when the temperature's like zero outside and some wind. Everything becomes slower to accomplish, like using Black Plastic Tape so I can appreciate what you're dealing with trying to get that project done! Every year I keep telling myself, I'm not going to work outside in the bittery cold weather but I find myself doing it anyway. Perhaps it's got to be the old saying that putting antennas up in Cold Weather Work Better!

Merry Christmas 2008 and Have A Happy, Healthy, Prosperous & Work A Ton of DX in the New Year of 2009!

Dan
WA9WVX