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k40 antenna's
- Thread starter minitrucker
- Start date
K-40 makes a good antenna, they have one problem though. They use a Capacitor in the base to get the SWR flat across all 40 channels. When you dead key more then 100 watts into one you are asking for trouble. Keep your dead key below 100 watts and probably below 80 to be safe. If you do blow the Cap you will know because your SWR will be 2.5 and nothing you do will fix it.
K40s I had over the years could handle 250 pep no problem , i believe they are rated at 500 pep but that's pushing it with those antennas because unlike base stations that stay in one place ,vehical antenna's can get into unkindly swr situations by basically being in the wrong place at the wrong time , so I'd keep it around 250 and you should be good to go.
I ran my S9 and a 4x1446 box into mine for years with no problems. The mag mount did mess up the paint, so I roof mounted it. Never had a single issue with the capacitor, and swr was always low.
I have them on 4 of the company trucks, roof mounted and they all have 2x1446 boxes into them, with no issues.
On My personal truck, I switched to a Wilson 5000 in the same hole when I up-sized to 2-2290's X 8-2879's.
I have them on 4 of the company trucks, roof mounted and they all have 2x1446 boxes into them, with no issues.
On My personal truck, I switched to a Wilson 5000 in the same hole when I up-sized to 2-2290's X 8-2879's.
Do like these guys said and you should be fine. When I had my 667 I smoked two K-40's and a Radio Shack 1000 watt open coil antenna before I bought my Wilson 5000. Just remember keep the dead key under 100 and you should be fine.
A K-40 rep once told me years ago that, if the K-40 trunk mount was well grounded to the car, you can push the whip all the way in the coil, mark it at the base, then pull it back out exactly 1/4" and lock it down and would have 1.1 to 1.5 swr across the entire cb band and beyond (that was true with mine) and could handle up to 500 watts. I used one for years with about 200 watts with no problems until I forgot to take it off one day while going thru an automatic car wash (the coil just twists about a 1/2 turn and comes off the mount). It was replaced with a wilson. I really did not notice that much difference between the two but that’s just my 2 cents worth lol.
your right DJ , I never really noticed a diff either between the 2 , just that i honestly felt that the Wilson's were built better ,took more power and didn't have the cap to deal with. But all in all , The K40 is a damned good antenna as far as IM concerned , it unfortunatley had to take a back seat to the Wilson.
back in the day before the Wilson's , man you either had a Fransis or 102in SS or a K40,they were what Wilson's are today and for the last 17 years or so. I'd like to think that Wilson took the idea from K40 , and if I remember correctley ? there were some law suites there after but even still , Wilson just uped the ante on them , just better all the way around , I even think the Wilsons' were lighter but with less hardware then the K40s , and you could change the coax without any problems. K40s had there time in the lime light until Wilson basically out did them. The old timers that are still around still use those K40s but they also know there limitations concerning power as well. IM sure they still sell fairly well because there still around.
........It can be replaced, but with alot of work. First take a desoldering tool (solder sucker) and after removing load, remove the solder from the top of the mount. Now the fun part...take a small flat screwdriver, and gradually pry up the cap on the bottom (looks like an old metal bottelcap) where the coax goes in. Be sure and pry up on the cap and not the plastic lip that the cap snaps over. It all comes out together (coax. "bottlecap" and capacator) When you put the new coax on, make sure everything goes back the same way.....especially the capacator. I've done a few with good results......I just wish they were as easy as the Wilson.zumlin said:
...runna pile-up on 6m SSB