Quad Antenna JavaScript Calculator
Above is the link that hookedon6 posted for us. Just enter 27.205mhz so we can compare the results to some SE L4+ dimensions I’ve posted below.
Here are the dimensions I have for the L4+ model. As I understand it, add on kits come in units for additional elements, and they are probably all the same dimensions. So each element past director #1 will be equal or close to 72.25” spacing and 422" in wire length. This is just my assumption however based on studying the L4+ instructions, and asking questions about this antenna for some years.
Boom = 17’ 10”
Spacing
R to Dr=84.25”
Dr to D1=56”
D1 to D2= 72.25”
Wire lengths as best I know,
Reflector=453”
Driver=438” Driver wire per side=109.5”
Director1=425”
Director2=422”
based on the above information any following directors will also be 422”.
6.0 Liter, I can’t be sure what frequency the SE L4 was designed for, but understanding it’s for CB I assume these measurements are close to the lower end of 27 mhz up to about 27.205.
So, compare these measurements with hookedon6’s link for a Quad calculator above, and you will see that Robb’s claim that all Quads are the same dimensions…might not be as truthful as he would have us believe. I don’t believe the Quad generator that HO6 gave us is accurate for this antenna either, because there is no adjustment for the wire diameter, whatever it is. That might make some difference too.
I’m also not sure whether the unique feeder device, itself, used by SE makes a difference in overall dimensions it has, but I wouldn’t be surprised if it did.
SE made these antennas at least as far back as 1978. That was before antenna modeling was available to the average Joe, just like Robb has noted. We didn’t have the personal computer at the time either. However, NEC was developed in the late 70’s and it was based in large part on math and science developed years earlier. I wouldn’t be surprised if the guys at Signal Engineering were smart enough to use such math and engineering to come up with their matching idea for this dual polarity Quad, even without the use of a computer. The dual polarity feature was what was very unique as Quads go, but I think the feeding idea itself…might be quite a bit older in other applications.
6.0Liter, you might be able to set this antenna up with a vast variety of dimensional difference and it still work, but I would first try to get it working as close to specks as possible. If you keep some good notes during construction and testing, you might even be able to detect some differences in performance using your radio.
From my personal experience with a friend who has a L8 that is over 60 miles away, we can talk just about any time using less than 5 watts on SSB after we get each other’s attention that we’re on the air.
6.0Liter, it you measure any of your kit, let me know how your numbers jive with mine, OK? I think your measurements for the fist 4 elements should be about the same as my L4+ measurements above.
