Let me first say that I am a big fan of MFJ. I have no bone to pick with them, and I realize this is an inexpensive antenna partly or wholly mfg in China. Not being my only antenna, I will use it on all the ham bands from 6 meters through 1.2 gigs (someday). Right now I really love the raised lobes on the aircraft band, and it really really pulls in those aircraft in central NJ!!
At these prices, ($ 70.00), I think I will choose to fix the antenna myself because I am capable. But I think everyone should know what the story is. So, read on and look at the two .jpg pics...
One cone element fell out as I was carefully assembling them to the center hub. Another dropped off in the back of my pick-up. Several Cone elements have fallen out in 30 MPH wind. I brought the antenna down and with two fingers, I was able to rock out the remaining 5 or so elements. Brand new antenna.
Had no problem so far with the 8 disc elements or the base loaded low band vertical element.
The CONE element length of 36" measured as received from manufacturer, from the tip of the aluminium rod to the end of the ferrule, less the threads which would be screwed into the hub. (I happen to have attached a washer and a flange nut to protect the threads to this one element that I unsuccessfully tried to press and drive all the way home, into the ferrule. I achieved the same .64" penetration as it the manufacturer did.)
The marks left on the aluminium rods from the pressing process are visible in attached .jpg pics. ALL the elements were not driven or pressed into the ferrule but for a mere .064" which is a 1/6th of an inch! The DEPTH of the ferrule is nominally .605" If the elements were properly pressed into the ferrule I would of not of been able to dislodge them.
Now I ask you all:
1) Would you feel safe having your children or the general public standing under this antenna, without some modification or improvement?
2) Is the intended length of the cone elements 35-1/2" or 36" as measured? (Ahh, it's a discone, and this dimension isn't that critical, is it?)
Some measurements and comments:
The aluminium rod is .196 diameter and just over 35-3/8 long. The ferrule is cut about .605 inches deep with inner diameter around .186", but for a .1" deep insertion shoulder cut to .205" that centers the rod within the ferrule as it is pressed home. The rod would definately be a good tight fit if it was pressed or driven in all the way. But the way I received this antenna, the rod was inserted to about 1/3 of it's diameter, or .064"!!
Measured the ferrule depth at a total of .605" including the shoulder which is about .1". The rods are a little over 35-3/8" long. If they were fully inserted within the ferrules, the cone elements would be a total length of about 35-1/2", (less the threads, of course).
Comments are WELCOME. Please let's not trash MFJ, OK?
holmzie N2EXG
At these prices, ($ 70.00), I think I will choose to fix the antenna myself because I am capable. But I think everyone should know what the story is. So, read on and look at the two .jpg pics...
One cone element fell out as I was carefully assembling them to the center hub. Another dropped off in the back of my pick-up. Several Cone elements have fallen out in 30 MPH wind. I brought the antenna down and with two fingers, I was able to rock out the remaining 5 or so elements. Brand new antenna.
Had no problem so far with the 8 disc elements or the base loaded low band vertical element.
The CONE element length of 36" measured as received from manufacturer, from the tip of the aluminium rod to the end of the ferrule, less the threads which would be screwed into the hub. (I happen to have attached a washer and a flange nut to protect the threads to this one element that I unsuccessfully tried to press and drive all the way home, into the ferrule. I achieved the same .64" penetration as it the manufacturer did.)
The marks left on the aluminium rods from the pressing process are visible in attached .jpg pics. ALL the elements were not driven or pressed into the ferrule but for a mere .064" which is a 1/6th of an inch! The DEPTH of the ferrule is nominally .605" If the elements were properly pressed into the ferrule I would of not of been able to dislodge them.
Now I ask you all:
1) Would you feel safe having your children or the general public standing under this antenna, without some modification or improvement?
2) Is the intended length of the cone elements 35-1/2" or 36" as measured? (Ahh, it's a discone, and this dimension isn't that critical, is it?)
Some measurements and comments:
The aluminium rod is .196 diameter and just over 35-3/8 long. The ferrule is cut about .605 inches deep with inner diameter around .186", but for a .1" deep insertion shoulder cut to .205" that centers the rod within the ferrule as it is pressed home. The rod would definately be a good tight fit if it was pressed or driven in all the way. But the way I received this antenna, the rod was inserted to about 1/3 of it's diameter, or .064"!!
Measured the ferrule depth at a total of .605" including the shoulder which is about .1". The rods are a little over 35-3/8" long. If they were fully inserted within the ferrules, the cone elements would be a total length of about 35-1/2", (less the threads, of course).
Comments are WELCOME. Please let's not trash MFJ, OK?
holmzie N2EXG
