Several people have asked for more information regarding how I raise and operate 6m yagi antennas during portable operation.  This page is meant to be an interim answer to address that procedure.

Full credit for the great videos documenting the way the portable mast is raised and lowered during the DN34 grid DXpedition go to K7SGP.  We had discussed the possibility of producing some sort of step by step video to show the parts in more detail, but we simply did not have time. However, I have no doubt that the information would help others in their efforts to activate rare grids.

When I am on 6m EME DXpeditions, I use the larger 6M8GJ yagi and M2 Portable Mast, both of which come apart into 44" long telescoping sections for easy transport as checked luggage on airplanes.  The methods used to erect that antenna are the same used on these recent grid DXpeditions.  There are some photos here on my website that will answer some of your questions - the last section of this page, entitled "MAST GUYING AND AND ANTENNA RAISING" is the part relevant here:


You will notice that there are a couple of key points....  First, you need to tie the mast base to a ground anchor to it will not kick out when you start raising it.  The second trick is to attach the "halyard" (the line that is used to raise the mast) to some fastener so that it will hold the mast from rotating as you pull it up.  On my EME system, I use an eye bolt connecting the last mast section together to provide this secure spot to pull on.   On the portable mast for these grid DXpeditions, I simply used stainless steel hose clamps to hold a small right angle shelf bracket to the mast so when I attach an S hook to it to pull it up, the mast does not want to rotate.   If the yagi is attached perpendicular to the halyard attachment, the antenna will just be smoothly raised and lowered at right angles to the ground, without spinning around out of control and bending the elements.

The height of the Falling Derrick used depends on the amount of leverage you need to raise the mast with the antenna on it.  On my EME setup, the 6M8GJ weighs around 50 pounds with the elevation mount and boom truss assembly, and it is up about 20' to 21'.   I use a three part telescoping Falling Derrick that gives me about 10' of height.   You will notice that I made a simple base out of angle aluminum for it so it won't dig into the ground (or sand) an can rotate as the mast is raised. Typically, the base of the Falling Derrick is set near the base of the mast.   I put knots next to each other in the halyard so the notch in the top of the Falling Derrick simply holds the rope by virtue of it fitting into the slot.  The knots dictate the location of the Falling Derrick, and how much leverage you will have in raising the mast.

In the video below by K7SGP, I also put black electrical tape around the rope to hold it in the slot, so it would not fall out while I was trying to get the Falling Derrick set up. I didn't have so much leverage as I could have if the knots were slightly farther down on the halyard, so the Falling Derrick was  slightly more upright at the beginning.  However, by backing up a bit further and applying more force, I was able to raise it easily.   On these grid DXpeditions, I used a lightweight aluminum mast (2" telescoping down to 1.75") that was about 25' long, so the antenna could be mounted at about 24.5' above the ground.  I just bolted together some lightweight pieces of aluminum tubing that I was able to find at the junk yard.   The Falling Derrick used with it was made from screwing together three 5' sections of threaded aluminum from the hardware store (sold as extensions reach out and smooth concrete floors):


You can see that the mast is set on a "Prop" to provide clearance for the yagi to be bolted to the mast before the it is raised.   The prop is simply adjusted by slipping a piece of aluminum tubing inside another, and holding it at the proper heigh with a hose clamp to prevent it from collapsing.   The Prop is held upright by  three small guy lines held in place with tent pegs.   Since the only force on the Prop is straight down, the only important thing is that the top of the prop (with the part shaped to accept the mast) be held firmly in position. By holding the Prop in position, it will be ready to catch the mast when the antenna is lowered again:


Here is how the larger antenna was raised last summer in KH8.   Now you can see why I taped the Falling Derrick between the knots on the halyard during the recent grid DXpeditions:


You can see how it might be necessary to have some help lowering the antenna if the prop has moved slightly during operation.  In this I tripped a number of times over the guy lines for the Prop during the middle of the night when I was out aiming the antenna, so the prop was slightly out of line.   You can also see why I taped the halyard to the Falling Derrick during the recent grid DXpeditions


When possible, it helps to be able to set up the antenna so you raise it with the wind and lower it into the wind.  It also helps if you have another person to "walk the mast" up or down as you raise or lower the antenna (although one person can do it alone).  Here is a film clip of lowering the 6M8GJ at the end of the 6m EME DXpedition to Fiji:


The key to success in this whole operation is to make sure that the SIDE MAST GUYS stay tight during the entire raising and lowering process.  If you have a flat site, this is easy - the guys just have to be anchored out away from the base of the mast the same height that they are attached to the mast. Of course, when you attach the guy lines to a bearing plate, as I do, the actual height on the mast is calculated as to where the guy lines would extend to the center of the mast.   If the height of the attachment (H) is equal to the distance out to the guy anchor (also H), the guy length is then:

L =  Square Root (2H^2 ) = 1.414 H

In practice, it is good to have the guy lines be a bit longer than the above calculation, since the exact location of the guy anchors may have to be adjusted for the slope of the ground.  If the ground is uneven, you may have to do some adjusting of the length and position of the side guys before the antenna is mounted, to make sure that the mast can be raised smoothly with the side guys remaining tight.  That way, the antenna can be raised without getting out of control, and when it is lowered, it will be guided directly back down onto the prop again.   So, the first step is actually to practice raising the mast by itself to make sure you have the side guy lines properly set:

https://www.youtube.com/watch?v=J1fC_-qGivI&feature=youtu.be <http://youtu.be/J1fC_-qGivI>

The front and rear guy lines can be whatever lengths are required to provide good stability and also hold the mast vertical.

To aim the antenna, use an AIMING CIRCLE mounted so the mast just fits through it.   The antenna is held at the desired azimuth by using small diameter nylon lines tied to the boom.   The lines are then secured to trees, or guy anchors and adjusted in length until the antenna is aimed in the proper direction.  Care must be taken not to put excessive downward tension on the antenna, or you will bend the boom or cause it to point upward or something...the goal is to prevent it from moving side to side, so the further out away from the antenna and the higher you can tie off the lines, the better!

I hope this helps answer the basic questions of how I do it on my portable operations, and is of use to others in setting up for portable operations.  Let's do more 6m DXpeditions!!!  

GL and VY 73, Lance