Wich is the best 160m antenna ?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by CU3AK, Aug 20, 2010.

Thread Status:
Not open for further replies.
ad: L-HROutlet
ad: l-rl
ad: Subscribe
ad: L-rfparts
  1. K9STH

    K9STH Ham Member Staff Member QRZ Page

    AAT:

    If you don't want to use a tuner then put a 4:1 balun on the 300 ohm feedline and use 75 ohm coax. Or, make a 6:1 balun and use 50 ohm coax.

    You might as well reduce the power from your transmitter and that will "protect" the finals just as much, if not more than, putting a resistor in the antenna. Also, your electric bill is going to be less!

    Or, do as Tom suggests. Even better, put a dummy load up as an antenna and then use Radio Shack 50 ohm coaxial cable. The radiation from the feedline should work as well as, possibly even better than, putting the resistor in the antenna.

    Glen, K9STH
     
  2. K5BO

    K5BO Ham Member QRZ Page

    Don't ask me

    I don't know much about 160, I'm just trying to get in on the fray about dummy load antennae again. Ok not true and not a good joke either.

    My best 160 meter antenna was a very tall light pole, near the Red Roof inn. It used to be next to the air port in Milwaukee. I stayed there one winter while attending the GE training center and Marquette U.

    Because of the snow I was able to hide a transmission line going out the window of my hotel room. The only possible antenna was a light pole, there were some big ones. The feed was two pieces of conduit with heat shrink tubing acting as a capacator diaelectric. The top cap plate coupled to the pole by jamming it on a rivet, seems like a bad connection but it worked. At the bottom cheap coax went to the opposite capacator end insulated off ground and to the lightening ground for thr pole.

    First sign of snow melt I had to scrap it for fear of being kicked out of the hotel, losing my place in the training center, and getting fired all in the same day.

    Conclusion: Big tall verticals with lots of loading at the top (like lights and mounting brackets) work pretty good on 160.
     
    N5WVR likes this.
  3. W0BTU

    W0BTU Ham Member QRZ Page

    There's a lot to be said about top loading, yes. I'm using an inverted-L with two elevated, folded radials, but the next antenna will likely be a T antenna with buried radials per ON4UN's Low Band Dxing book.

    In only a few weeks late last winter, I was able to work 30 countries on 160 CW, transmitting on the inverted-L and listening on my Beverages. I can't imagine that anything could possibly have been more fun. :)
     
    Last edited: Aug 21, 2010
  4. KC8VWM

    KC8VWM Subscriber QRZ Page

    For further information on VE3DO's linear load concept, go to pages 9-18, 19, 20 and 23 of ON4UN's "Low Band DXing" book, second addition.

    Also pages 9-38 to 44 of the 3rd edition.
     
  5. N9AAT

    N9AAT Ham Member QRZ Page

    Well, back to the issue at hand (since nobody likes T2FD's too much) there's another thing I'm also considering for 160, and that's shunt-feeding my BX tower once I get it in the air. I have a big ole variable cap that ought to do the trick. So what think of THAT?
     
  6. NA0AA

    NA0AA Ham Member QRZ Page

    How tall is the tower going to be? In general it should work well, and the more aluminum you have on top of the antenna for top-loading, the better it should work.

    Obviously you are going to need some sort of counterpoise.

    The antenna book has a pretty good section on loading towers - you can also feed an elevated groundplane with the positive and use the grounded tower to the shield.

    I think the reason most people don't favor the T2FD design is the waste of power, however, if you build one as a single band antenna - tuned for the band, then the resistor will only take the edges off the band and might reduce losses, but since it's essentially the same size as a simple folded dipole, you might as well go that way and save the complexity and cost of the resistor bank.

    Not to distract anyone, but can you imagine if we get a 600 meter allocation? Imagine the work needed to get a signal out on that band.
     
  7. N9AAT

    N9AAT Ham Member QRZ Page

    Back again. Gone for a couple of days. One of my TACAN sites took a lightning hit last Sunday and it's been a long week. Do NOT want to have to replace the antenna, but looks as if have no choice. Tired.

    Anyhow, CU3AK started this thread. Don't know if he's still around or not.

    WOU, back to the TFD thing. Here's my point: A TFD is indeed nothing but a resistor in space, or a dummy load if you wish, but at least it's up there on the antenna rather than down inside my finals. Anytime I'm off resonance it seems I'll be having some reactance and therefore some power reflected back into my system. It has to go one of three places; burned up in the transmission lines, added to the inefficiency of my PA, or warming up a TFD resistor. It seems that the third choice would be preferred since supposedly nothing comes back down the line at all. Yeah?

    I mean, if you're off resonance you're off resonance. Yeah?
     
  8. NA0AA

    NA0AA Ham Member QRZ Page

    Sorry to hear about the TACAN site - complex I'm sure.

    I have to admit that your arguement makes some sense - but I guess my point was that the poster seemed to indicate that he wanted it as a single band antenna presumably he can make it resonant - at that point, provided you have a small tuner, the resistor bank is not really going to do anything for you.

    And I don't mean to get pendantic about it - the antenna makes sense for a number of installations but as a monoband antenna it seems to be overly complex and costly.
     
  9. W8JI

    W8JI Ham Member QRZ Page



    Not to me.

    He seems to think it is a good idea to burn the power up, even on "good frequencies" where the burned up power would have been radiated.

    Apparently he has never heard of an antenna tuner, trap antenna, fan dipole, or any number of better options than a resistor in parallel with an antenna. :)
     
    K5ZO likes this.
  10. W8JI

    W8JI Ham Member QRZ Page

    That's a terrible antenna idea.

    While the SWR is good, that antenna feed method can easily lose several dB of power heating the earth!!!

    I'm really surprised the "antenna book" doesn't warn people what a poor feed method that is.

    73 Tom
     
Thread Status:
Not open for further replies.

Share This Page