A148 20S 2 Meter Yagi Array. Please also see the A148 10S. Amateur Antennas The Cushcraft A148 20S is a complete 2 meter antenna array with two ten element Yagis, stacking frame, harness and stainless steel hardware. Just built a Cushcraft A148-10S 2 meter yagi beam. Hooked up 75ft of Lmr 400 to it and ran a test with my MFJ 259B. The antenna is only 5ft off the ground and is vertical. I also built the antenna to spec from the supplied instruction manual. I found the SWR to be around 1.4 at 144, 1.6 at 145.00 MHZ, 1.4 at 147.00 MHZ, and 1.3 at 148.00.

• Cushcraft A148 10s Manually 10
• Cushcraft A148 10s Manually To Iphone

In article (Paul H. Bock) writes: In a recent on-the-air discussion, I pointed out the error of mounting a two-meter yagi in the vertically-polarized position while using a metal mast (assuming that the antenna mounts from the center of the boom and not at one end. One of the on-the-air participants, admittedly a new ham, became very defensive and said that he used a Cushcraft A147-11 vertically polarized on a metal mast, and his antenna 'had directivity.' According to my simplex pal across town, his Cushcraft yagi manual actually says to mount them that way or at least it has pictures of the yagi vertically mounted with the mast sticking up only a couple of inches above the boom.

Other weirdness in the Cushcraft manual is a picture showing the coax routed across the top of the insulated elements. Maybe the marketing folks at Cushcraft took all the pictures.

I've seen their collinear arrays upside down in magazine ads. 1) I assumed that a metal mast, being in effect a non-resonant 'extra' element suddenly stuck in the middle of a parasitic array, would detune the antenna and probably throw the radiation pattern off by creating either more than one lobe or skewing the main lobe above or below the plane of the array by some noticeable amount. Is this assumption anywhere close to correct? I've heard that if you have to do it, then stick the mast up until its even with the top elements so as not to destroy the symmetry so much.

I've modeled both ways with the MN antenna program and it screws up the pattern pretty good but mostly at the expense of forward gain. My real experience is not so easily measured but I know a 7 element 2 meter yagi improved for both vertically and horizontally polarized signals after I mounted it horizontal. Previously I had tried both metal and wood masts but still ran the coax down the wood mast with the yagi vertical. The coax will also become an unbalanced and unwanted element this way. My KLM 2M14C circular yagi manual says to mount the thing on a non-conductive mast or boom and run the coax off the back end.

It works okay this way. I found a telescoping fiberglass broom or window squeegee pole at the hardware store that is pretty strong and about 6 feet long when collapsed. You only need to get about 4 feet away from metal but 6 or 7 feet is better at 2 meters.

I don't know what others think about this but the only place for a metal mast on a vertically polarized yagi is on the end where it may act as a reflector. Better yet, buy two yagis and cophase them on a horizontal boom. WA7LDV Paul H. A couple of followup comment from the original poster: One of the on-the-air participants, admittedly a new ham, became very defensive and said that he used a Cushcraft A147-11 vertically polarized on a metal mast, and his antenna 'had directivity.' NOTE: My on-the-air comments did not suggest the antenna had 'no directivity', only a screwed-up pattern, but the 'defensive' ham took it that way. pattern off by creating either more than one lobe or skewing the main lobe above or below the plane of the array by some Poor choice of words; 'above or below the plane of the array' implies the antenna is horizontal when it isn't; what I mean here is that the major lobe no longer points in the same direction the antenna is pointed because of the deleterious effect of the metal mast, which is now parallel to the parasitic directors and has a detuning effect.

( ). Paul H. K4MSG. Internet: ). Senior Systems Engineer. Telephone: (703) 560-5000 x2062 'You can have my bug when you can pry my cold, dead fingers from around it.' - anonymous radiotelegraph operator Paul H.

Cushcraft A148 10s Manually 10

In a recent on-the-air discussion, I pointed out the error of mounting a two-meter yagi in the vertically-polarized position while using a metal mast (assuming that the antenna mounts from the center of the boom and not at one end, the latter being common for 3- and 4-element yagis). One of the on-the-air participants, admittedly a new ham, became very defensive and said that he used a Cushcraft A147-11 vertically polarized on a metal mast, and his antenna 'had directivity.' So, I have a couple of questions based on my assumptions as follows: 1) I assumed that a metal mast, being in effect a non-resonant 'extra' element suddenly stuck in the middle of a parasitic array, would detune the antenna and probably throw the radiation pattern off by creating either more than one lobe or skewing the main lobe above or below the plane of the array by some noticeable amount. Is this assumption anywhere close to correct? 2) I once heard two hams testing a A147-11 which ham A had just installed, and he was trying to figure out why station B was stronger when the antenna was about 30 degrees off-azimuth from Station B's known location (the antenna was vertical, BTW, and the two stations were about 60 miles apart). Ham A was using a - you guessed it - metal mast. Does this result sound reasonable?

3) Has anyone out there ever purposely installed a yagi array vertically using a metal mast and tried to measure the effects (VSWR, azimuthal pattern accuracy, etc.)? I have a A148-10S which is currently mounted horizontally, and have been toying with rotating it into the vertical plane and trying to measure the effects, but maybe someone else has tried it out of scientific curiosity. ( ). Paul H. K4MSG. Internet: ).

Senior Systems Engineer. Telephone: (703) 560-5000 x2062 'You can have my bug when you can pry my cold, dead fingers from around it.' - anonymous radiotelegraph operator Jan Chojnacki 11:40. 1) I assumed that a metal mast, being in effect a non-resonant 'extra' element suddenly stuck in the middle of a parasitic array, would detune the antenna and probably throw the radiation pattern off by creating either more than one lobe or skewing the main lobe above or below the plane of the array by some noticeable amount.

Is this assumption anywhere close to correct? I've installed a Yagi vertically mounted on a metal mast and I experienced detuning. I couldn't tell you how the radiation pattern was affected since at the time I had no way of determining that - but since I was operating on 2m, I installed a horizontal counterbalanced boom and remounted the antenna a few feet away from the mast. That seemed to help a good deal, although there was still a little bit of detuning remaining.: If you eat a live toad first thing in the: morning, nothing worse will happen to you all Fido: 1:153/7116: day.

Amateur Radio: VE7FJC: To you or the toad. William P.

Osborne 07:18. On Thu, 28 Apr 1994 20:55:12 GMT, Paul H. Bock wrote: In a recent on-the-air discussion, I pointed out the error of mounting a two-meter yagi in the vertically-polarized position while using a metal mast (assuming that the antenna mounts from the center of the boom and not at one end, the latter being common for 3- and 4-element yagis). Paul: This is an excellent problem for testing with the newer versions of MIninec or NEC on the market. I have done a good bit of modeling of stacked and interlaced 10/15/20 meter yagis and can confirm that a 20 meter element in the middle of a 15 meter yagi is bad news in that it can cost you 1 to 1.5 dB of gain, change the input Z some and cause most anything to happen to the front to back. I have not tried a random length mast but I would expect the same sort of results.

73 Bill John Boyer 04:01. Osborne wrote:: On Thu, 28 Apr 1994 20:55:12 GMT, I did a little modelling with NEC. I first constructed a rough 4 ele yagi and got a resonable pattern.

Then I added a long vertical pole roughly in the center of the yagi. This really buggered the pattern. Ok so I did this at Band II where I have a good idea of the size of things off the top of my head, but it still applies to 2m. Here is my NEC input file. CM vertical Yagi CM CM CE GW1,25,0.,0.9.,0.9.01, GW2,25.76,0.76.76,0.76.01, GW3,25,1.3,0.6,1.3,0.6.01, GW4,10,1.9,0.6,1.9,0.6.01, GW5,25,1.,0.,-2.65,1.,0.35.03, GE0,0,0., EX0,2,13,00,1.,0., FR0,1,0,0,96.,0.,0., RP0,1,359,1010,90.,0.,0.,1.,0.,0., EN So I guess the answer is don't use a metal pole with a vetical yagi. John B Robert Casey 21:59. In article (John Boyer) writes: So I guess the answer is don't use a metal pole with a vetical yagi.

My father used a wooden pole to mount a vertical yagi, but I pointed out 'what about the coax running up the wooden pole to get the radio connected to the antenna?' He figured that, yes, it will have some effect, but the coax being smaller than a metal mast, would not be as bad. Don't really know. Would it help if we used ferrite beads on the coax spaced something like one every 1/6 th of a wavelength (or some such smaller than 1/4 wavelength) to be nonresonant?

Idea is to 'break' up the coax into many short pieces to RF on the outside, so it looks like non-significant short pieces of wire.? Zack Lau (KH6CP) 08:17. Bock K4MSG wrote:: 3) Has anyone out there ever purposely installed a yagi array: vertically using a metal mast and tried to measure the effects: (VSWR, azimuthal pattern accuracy, etc.)? I have a A148-10S: which is currently mounted horizontally, and have been toying: with rotating it into the vertical plane and trying to measure: the effects, but maybe someone else has tried it out of: scientific curiosity. Kent Britian measured a 2.2 wavelength 435 MHz DL6WU yagi on his test range. With the mast all the way through the yagi, the gain varied by +1 to -10 dB.

Cushcraft A148 10s Manually To Iphone

With the mast half way through the yagi, the gain varied by +1 to -6 dB. There appear to be more spots to put the mast in without degrading it too much, but this might be yagi specific. He varied the spacing between the driven element and the mast. The results appear in the 1993 AMSAT-NA proceedings (11th) - Zack Lau KH6CP/1 2 way QRP WAS 8 States on 10 GHz Internet: 10 grids on 2304 MHz Jim Grubs, W8GRT 10:57. (Robert Casey) writes: In article (John Boyer) writes: So I guess the answer is don't use a metal pole with a vetical yagi. My father used a wooden pole to mount a vertical yagi, but I pointed out 'what about the coax running up the wooden pole to get the radio connected to the antenna?'

Why not make the radiator a co-axial sleeve antenna and rotate directors amd reflectors around it? /- Jim Grubs, W8GRT Voxbox Enterprises Tel.: 419/882-2697 6817 Maplewood Ave. Fido: 1:234/1.0 Sylvania, Ohio 43560 -+-/ Paul H. (Robert Casey) writes: My father used a wooden pole to mount a vertical yagi, but I pointed out 'what about the coax running up the wooden pole to get the radio connected to the antenna?' He figured that, yes, it will have some effect, but the coax being smaller than a metal mast, would not be as bad.

Don't really know. Would it help if we used ferrite beads This problem has occurred to me as well. Your father is probably correct about the effect being less than that of a metal mast; but I think that if optimum performance was my goal, I'd run the coax along the boom to the reflector, then tape it to the back of the lower half of the reflector and let angle away from the antenna downward to the mast. Not a nice, clean installation, to be sure, but probably minimizes the effect.

The alternative is the counterbalanced horizontal boom idea suggested by someone else, but if I were going to do that my 'counterbalance' would be another antenna so I could pick up the extra 3 dB gain. K4MSG jmva.@cen.ex.ac.uk 08:27.