Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KZ4USA, Nov 4, 2017.
It's about 10%.
It's a pole. A pole.
234/57 Feet = 4.11 Mhz resonant frequency (1/4 wavelength).
Second harmonic = 8.22 Mhz
Third harmonic = 12.33 Mhz
Anything that can conduct electricity can matched to 50 Ohms with the right tuner. F0r minimum losses put the tuner at the antenna base. Otherwise losses will occur in coax. 110 ft coax converts high standing waves to heat i.e. losses.
I not that worried about the losses on a 110' of LMR-400 at HF frequencies. You don't have to sell me on remote tuners, I agree they are the best solution for a non-resonate antenna. I've had great sucess with the AH-4. However, I'm now dealing with an amp and I don't have a remote tuner that will handle 500 to 1000 watts. It will be interesting to compare the performance difference once I get the remote tuner.
Anyway, this isn't my thread so I'll set my pole aside for now.
Thats alot of heat I would think if you are running 1500watts,
I ran the numbers for LMR-400, 110ft, 3:1 SWR at the antenna, for 1000W input, about 150-200 watts converted to heat in the coax. 5:1 was over 250W loss. That's about 1w and 2W per foot dissipation which probably isn't going to melt the coax.
Still, arbitrarily using 110ft when you don't have to is nuts. Shame on Five-Zer0 if they recommend that!!
I don't know what the real SWR load numbers are for this antenna on 40m and 20m. I suspect much higher. Need to run a model on EZNEC.
This rig will run 500W most of the time and 1000W on occasion. Even if the losses are 20% at 500W, that is still 400W at the vertical. I could sell the amp and just run barefoot with my AH-4 or I can keep the worms warm and put out 400W at the same time! Happy worms and a better signal is good enough for now. However, you are really preaching to the choir about remote tuners. I think a few of them are very good...
Sounds like you are better to use the GAP Voyager for 160,80 and 40 which is tuned for those bands. The use another vertical for the other bands like their Challenger DX and price would be the same for both of them of the cost of the 57ft.
I agree with your line loss calculations but, I didn't run 110' based on Zerofive's recommendation. I ran 110' because it's 90' to the vertical, 10' up to the support to the UNUN and another 10' at the shack side to my rig. I used an existing 3" pipe from an old large dish satellite installation. Any closer and it would be in the middle of the front yard and the XYL would have a fit. Besides, I'd rather have some distance between my body and the antenna.
If the argument is really resonate versus non resonate that's a different discussion. Remember, the saying that everything is a compromise? Well, if you want to work several bands on one "pole", there will be some compromises. If you have the space, time and resources to run several resonate antennas this is obviously the best solution. With the proper precautions to avoid remote tuner damage from static buildup and EM surges, the right remote tuner and non-resonate antenna is also a very good solution. If you are Ok with the compromise that tuning at the shack will result in 15-20% in worm warming line loss, that is an acceptable solution as well. I know exactly what remote tuner I want and it isn't cheap so I'll keep the worms warm until I'm ready to buy it.
Here are a few photos of my installation for the OP. I fabricated my own tilt over base and that took a couple of weekends with other obligations. I used a DOM tube for a support, some 1/4" cold roll and two axle bolts to attach to the existing 3" pipe. Yes, that's overkill but, that's the way I do things. The Zerofive 43' is well built and it went together very easy. I put it all together after work in a couple of hours and finished right at dusk. It has six radials but, two aren't showing up very well due to the lighting in the last photo.
Since installation it's seen some 40+ mph with without any need for alarm. In eastern Washington we can get some insane wind/ice storms and this why I built the heavy duty tilt over base. I'm slightly handicapped from arthritis and other issues but, I can still erect or lower the antenna without assistance. In case my physical situation changes for the worse I've added a ring to the DOM tube so a cheap boat winch can be used to raise or lower it.
Personally, I'll pass on the traps, loading coils, narrow bandwidths and high maintenance antennas. IMO, a non-resonant antenna and tuning is a better and easier solution. It all goes back to that compromise thing, you have to give it up somewhere. If you have some tall trees you may want to concider a 130' or so non-resonant end feed and remote tuned Inv-L. It will work 160-10 meters quite well.
Certainly the F-Z antennas are sturdier and essentially nil maintenance compared to anything else. Your considerations are entirely reasonable and practical! I'm not beating the drum for remote tuners. I posted the loss estimates to answer questions I had about longer runs at high power in response to a comment about LMR400 (It doesn't solve all problems). cheers, bill
Anyone considering resonant/trapped vs non-resonant verticals would need to compare overall system losses including coax type and length as well as patterns in view of their preferred bands and goals. No easy answers, but that is what makes radio so interesting and challenging.