The Ultimax DXtreme

The retired W1SFR
For the past few days, our weather here on the East coast has been excellent nice warm weather (up to +10) with no rain and just great sunny skies. On the second day of this great weather, I decided it was time to put up my new Ultimax DXtreme EndFed antenna. The antenna I have at present is the W1SFR KX3 helper EndFed antenna.  As I have said past posts this is a fantastic antenna, very well built and works as advertised. So why am I replacing this antenna with yet another EndFed antenna, this is a very good question and was answered in this post.
Ultimax size difference
When I took the KX3 helper down I was pleasantly surprised how great the balun enclosure looked. It has been up for over 6 months exposed all kinds of weather and looked as new as the first day it went up. The first step to get the new antenna up was to install the counterpoise that I ordered with the Ultimax antenna. The configuration for my EndFed antenna is the Balun end is in a tree about 25 feet high with the wire extending down to my shed and is terminated about 8 feet above the ground. This is the same configuration I am going to use for the Ultimax antenna as well. The counterpoise from Ultimax antennas consists of a single wire for about 6 feet and then it splits into 2 separate wires. I used a staple gun to secure the counterpoise to the tree trunk.  The only choice I had was to place one counterpoise leg on one side of the tree trunk and the other one on the opposite side. The tree is only about 1.5 feet around so the counterpoise wires are not that far apart. At the bottom of the tree, each counterpoise goes along the ground in opposite directions for about 15 feet.
The Ultimax antenna is rated at 2KW SSB with 14 gauge wire along with a hefty insulator. Since my max output will be 100 watts CW and tops 80 watts DATA the insulator and wire on the Ultimax is a bit too heavy duty. Plus my support at the wire end is a wooden pole that is not meant for heavy-duty support.
Ultimax is up. 
The idea was to use the wire from the W1SFR KX3 helper as so I thought at the time it was only 2 feet longer than the Ultimax antenna wire but very light. I folded over the wire to bring it down to 33 feet to match the Ultimax wire length and check the SWR on 80, 40, 30, 20 17 and 15m both with and without a counterpoise. The results show when using a counterpoise the SWR was not as good as without. I am guessing this is because of the position of the counterpoise, I was running out of time and not able to play too much with the counterpoise. We are expecting a very large snowstorm tomorrow so the antenna play is done for now. I am going to leave the antenna up without the counterpoise attached. BUT having said that the counterpoise is very easy to attach if need be.

Results without a counterpoise:
     Band              Freq           SWR
    80.              4.000.        7.0
    80.              3.500.        8.1
    40.              7.001.        1.8
    40.              7.070.        1.8
    30.              10.100.     3.3
    30.              10.150.     3.3
    20.              14.001.     4.6
    20.              14.070.     4.6
    17.              18.068.     2.5
    17.              18.168.     2.5
    21.              21.001.     1.5
    21.              21.070.     1.5
Results with a counterpoise:
         Band              Freq           SWR
    80.              4.000.        6.5
    80.              3.500.       9.1
    40.              7.001.       5.2
    40.              7.070.       5.2
    30.              10.100.     2.2
    30.              10.150.     2.2
    20.              14.001.     4.9
    20.              14.070.     4.9
    17.              18.068.     2.7
    17.              18.168.     2.6
    21.              21.001.     1.6
    21.              21.070.     1.5
Results from W1SFR EndFed:
         Band              Freq           SWR
    40.              7.001.        1.9
    40.              7.070.        2.5
    30.              10.100.     4.4
    30.              10.150.     4.5
    20.              14.001.     4.5
    20.              14.070.     4.3
    17.              18.068.     1.5
    17.              18.168.     1.5
    21.              21.001.     1.8
    21.              21.070.     1.8

Mike Weir, VE9KK, is a regular contributor to and writes from New Brunswick, Canada. Contact him at [email protected].

9 Responses to “The Ultimax DXtreme”

  • Frank ON6UU:

    Hi Mike,

    I’m surprised about these SWR values, I have several end-fed antennas and they all have SWR values of about 1.2-1.3/1 in the traditional bands, The SWR on the WARC bands is a bit higher but not the values you measured. For that matter I also have WARC band end feds which SWR is about 1.2-1.3/1. They are all home brew …. ..

  • Frank ON6UU:

    fyi, they are 49/1 baluns. No hassle.

  • Mike ve9kk:

    Good morning Frank and thanks for taking the time to leave a comment, my situation for the EndFed is less than ideal and with my LDG AT200pro2 tuner I am able to get a very decent match on the bands that have high SWR. The Endfed I used before this one was the same and no matter what I did things did not really change. The owner of Ultimax antenna is very open to emails and giving assistance so maybe this weekend I will reach out to him and see that input he has.
    Do you find the 49:1 baluns work the best with regard to Endfed configurations?
    Frank have a great weekend.

  • Harry K7ZOV:

    Hi Mike,

    Something is not right.. Are you 100% sure this is a true 49:1 unun or maybe someone shipped a 9:1 unun.. Or maybe the matching transformer in the box is missing the cap that usually goes across the coil.. As I said..Something is not right.

    Good luck

    73 to you and yours

    Harry K7ZOV

  • Mike ve9kk:

    Good evening Harry very nice to hear from you as always, Frank ON6UU in the previous comment was mentioning his EndFed antenna is using a 49:1. The Ultimax Endfed that I have has a 9:1 in it. I emailed the company today and I must say they got back to me in no time with several emails. They informed me that the preferred method of installation is to have the balun end at around 6 feet above ground with the counterpoise. I have the opposite with the balun end in the air at about 25 feet. In the spring when the snow is gone I will try it the opposite way and see how that works. At this time with how it is I am not complaining at all. The LDG tuner is able to get great SWR on all bands including 80m which I did not have with the other antenna. Also, I was having issues on 40m with the other antenna it would affect the washer and some capacitive touch lights in the house. With this antenna I have had not issues. So overall I am a very happy camper with the antenna and in the spring I will try it mounted the other way and see how that works out.
    Thanks for the comment Harry and have a great weekend.

  • Harry K7ZOV:

    Mike, The units that use the 49:1 work totally different for the units that use a 9:1 design. The 9:1 is a random wire matching transformer that you MUST always use a tuner with. The KX3/KX2/K3 internal tuners will load this up from 40-10 meter with as little as 33 ft of wire and if you go 50-75 ft of wire you can add 80 meters. As I understand it the 49:1 will take a resonate wire for say 80 meters and give you low SWR’s are 40, 20, 15 (in most cases) and 10 meters and so-so on 17 and 30 or not at all without a tuner. Generally you won’t need a ATU for the 49:1 as long as you have a 1/2 resonate wire to start with… Hope that makes sense. Tired tonight.

    I sent you a bunch of PDF files dealing with the 9:1 unun and how to make one. They are dirt cheap to make, esp for QRP or 100 watts. I think I also sent information on the 49:1 design.. Looks like it might be time to look them up

    BTW when I have used the 9:1 matchbox with a random wire and 25 ft of coax, I have never used any counterpoise. I used the shield of he coax. Over 25 ft I had issues and would add about 15 to 20 ft of wire. Thinking about it more.. I kept the matchbox on something that was none conductive and 6 ft or more off the ground.

    Hope this info helps. Contact me if you have any other question and check out the pdf files I sent you.

    Good night and have a great week-end. I am still playing with the new Log4OM version 2..It is awesome.. Also still learning theIC-9700 and figuring out how to get it to make nice with my two eggbeater satellite antennas, SATPC32 software and all that new “stuff” and terminology..

    73 to you and yours

    Harry K7ZOV

  • Cliff KU4GW:

    I’d stick with the W1SFR EndFed until the WX improves so you can get back to the experimentation. Good luck and very 72/73!

  • Mike ve9kk:

    Good morning Harry, thanks for the reply and I did get your PDF’s on the baluns they were read over tea during the evenings. I will say I think I just did a fast skim over of the 49:1 info as I was more concerned about learning more of the 9:1. Having said that I should have paid as much attention to the 49:1 documents as well. With this new antenna I do get a decent match using the LDG AT200proo2 tuner and it will even tune up on 80m for me and I have made some decent FT8 contacts there.
    Do keep me posted regarding the Icom 9700 it looks like a great rig and it would be a whole new open door to ham radio for me if I was to eventually go down the VHF/UHF all mode road.
    I will head into my PDF folder and dig out the 49:1 info and even refresh my memory on the other baluns as well.
    73 and have a great what is left of the weekend.

  • Mike ve9kk:

    Good morning Cliff, well the Ultimax is the antenna of choice that is up and running at the moment. Once the weather improves here in a month or, so I will be out and about with the antenna play!
    73 and thanks for taking the time to leave a comment.

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