Scott, you have described a classic case of an open start winding circuit. The most common cause in this part of the country is mud wasps building a nest around the start circuit throwout switch, cau
Drax, I looked into your backorder with TexasTowers. We have had the parts on order with Rohn since early August and still waiting for delivery. As of yesterday they are promising to ship midweek nex
Blair, that is not quite right. Using a 50 ohm swr indicator, the lowest swr is shown when the reactance is zero. Using a transmission line program, 40 ohm load 40+j0; swr=1.25. 40+j10=1.37; 40-j10=1
Steve, when I plug your numbers into a transmission line program I get these results:283.8 -j23.66 = 5.72 vswr (same as your example). 288.2 +j0 = 5.7 vswr which is just slightly lower than example #
There is a scenario that you are both correct: If the large vertical has quite high ground resistance in the beginning, the base impedance can actually be greater than 50 ohms. As radials are added,
Yes, in stock at Texas Towers. Call 1 800 272 3467. 73, Gerald Williamson, K5GW General Manager, Texas Towers In a message dated 12/5/2008 3:43:31 P.M. Central Standard Time, aa3b.bud@gmail.com write
What is a BFR? 73/k5gw In a message dated 12/24/2008 11:24:23 A.M. Central Standard Time, jruing@ameritech.net writes: I duck tape a light Dacron rope to a BFR and just throw it like a base ball. ==
John, I have built a number of antennas from 7MHz to 432MHz using YO and find the same impedance shift you mention. Apparently the algorithms don't accurately deal with this issue even though pattern
In general, as the stacking distance exceeds optimum, the mail lobe beamwidth continues to deacrease. The gain does not increase as one might expect because the grating lobe amplitude increases and "
Perhaps the .128" size is defined by the o.d. of the center pin which naturally is larger than the center conductor? 73, Gerald K5GW In a message dated 1/4/2009 12:26:53 A.M. Central Standard Time, s
Have you considered using a few snap on ferrite cores on the end of the matching sections where they connect to the driven element? 73, Gerald K5GW In a message dated 1/17/2009 2:34:37 P.M. Central S
Having sold thousands of 45G sections over the past 30+ years, I can state positively that 45G uses a joining sleeve on the lower end of the section. There is NO swaged joint on Rohn 45G tower sectio
The thimble installation goes much easier if you twist the legs away from each other, one left, the other right instead of prying them open. A couple of vise grip pliers makes this quick and easy and
If you scale this scenario to 2 meters, it is similar to using a 1.8 inch o.d. mast to support and rotate a beam antenna. This is done all the time with no apparent problem. 73, Gerald K5GW In a mess
Most antenna manufacturers are using 6063-T832 alloy tubing. The T832 is very important and I have seen no one refer to this in these tubing discussions. The yield strength of 6061-T6 and 6063-T832 i
Scott, 10:1 vswr indicates a GROSS mismatch. This can happen when there is a short circuit or open circuit between the coax and gamma match. Ian had a good suggestion about the N connector. If you co
I was under the impression that MOV devices are "damaged" somewhat during each protection event and eventually enough "damage" accumulates and they have to be replaced. Maybe someone with more knowle
Rocky, the major effect is the guy system uses up more real estate than normal guying schemes. The forces on the guy wires will be somewhat less and that could be a good thing. Gerald Williamson, Gen
John, try a google search for 4130 chromoly specification. Several hits will come up. Beware that the material is usually sold without the final heat treatment and to reach the yield strength you are
Gene's email is chock full of good ideas and advice. The serpentine step is a stroke of genius! A corrugated drain pipe can also be used if an additional step is added: where the pull cables and wire