Tuning GAP Titan DX
I had to remove the antenna last week-end due to maintenance works into the roof, so I took the occasion to play a little bit with the Titan tuing rods.
I Found this schema on the net originally made by CT1EFV based on the GAP picture.
I made some minor changes, expecially to the 10 meter part that based on what I read on manual and on the net, was wrong.
I’m sure this picture can help on tuning your antenna.
Hi Simone. I appreciate your information about how you selected the GAP Titan DX as your multiband vertical. I am also interested in the GAP Titan DX. As I read your blog, it has been almost 3 years since you put up your GAP. Do you still use the GAP Titan DX? Are you still pleased with it? Has it suffered any damage from weather/wind? I am interested in your comments about the antenna after ~ 3years of use. Thanks! Sam
Hello
Well after 3 years I can say I’m satisfied. Works very well on 12 15 17 20, is acceptable on 80m, can be better on 40 and 30 and I’m not satisfied on 10.
SWR is present in all bands with acceptable limits, <2.0 except on 30 where I've alwats had problems.
Aluminium is excellent and no problems even with strong wind, even if I've cabled it at the top as GAP recommends.
Worked 230+ countries with 100w.
How not to recommend it ?
Thanks for the update! I will keep this antenna in my consideration. 🙂
Hello Simone,
After setting up my Titan DX and taking swr readings I found that the 40M and 20M bands had the worst readings. At 7.0 mHz it is 4.1/1 and at 7.3 mHz it is1.3/1.
On 10M at 28.0 mHz. it is 4.6/1 and at 29.7 mHz it is 3.0/1.
Also, the best resonant point outside the 10M band was at 24.4 mHz with a 1.3/1 swr.
Do you think if I lengthen that little 10M segment on the counterpoise it would lower the resonant point into the 10M band?
Thanks for any advice you can give.
73, Fred
k6kub
Changing the 10m segment may influece 40m but don’t believe will impact on 20m.
The ant. tested much better with the analyzer with multiple wavelength coax instead of the 25 foot coax.
The 10M band then measured high with 4/1 swr. The previous owner replaced the the original 10M segment with one that is 4 feet long. I changed it back to 3 feet 8 inches and now the swr is 2.4/1. I will shorten it a little more.
It seems many people have the same problem on 30M. That tuner rod needs to be longer.
Hi Simone my name is Daniel i am busy the make the GAP TITAN DX its working 60-40-30-17-12-10 m i working DX on 60m 15watt with te states .I make counterpoise for 40m-60m
the question is how long is the low part to the isolator en the top part to the isolator ??
Ciao Simone,
My name is Bob, M0RDB.
I’ve been reading your article with great interest.
My installation is annoyingly about 400kHz off on most bands.
40m +200 kHz
30m -380 kHz
20m -580 kHz
17m +380 kHz
15m +300 kHz
12m +300 kHz
10m nominal
Had you had any success at moving the response to achieve a better match?
I wondered if trimming or extending the rods had made a difference? Or what about adding a capacitance hat to bring some of the bands down?
Grazzie
Bob, Since my last relocation I’m on band on several ones, except 30 and 40 mtrs.
I would suggest to make stubs longer, adding a small pice of electric cable to elements. I’ve succeeded some years ago on lowering resonating frequencies on 12 / 17 and 15.
Just to get an idea of what needs to be done, can you remember approximately how much wire you added to achieve resonance?
I might have enough aluminium to make new tuner rods.
Just a short one, 7-15 cm, depending on the bands. But if you have a such general problem probably, you have to lower the crosses holding the rods. Have you made a test in such way ?
Not yet.
I think if it’s 15cm, I might do new tuner rods for 12 and 15 and swap the 17 and 20 lower tuner rods over, so that 20 comes up and 17 goes down.
In fact looking at it, the 12 and 15 rods could swap, and that extended 15 rod could be replaced with a full 1.3m.
I still cannot work out what the short top tuner rod does though?
Sadly, no-one has a suitable way of modelling it before I go up the hi-lift.
This GAP works only with BLACK MAGIC- just have to have the right wand. Keeps
you guessing.
Hallo, i use gap titan antenna 20+ years and you all must onderstend that top capacitor decide center of frequencie for rest of antenna. If u use 3.7mhz center capacitor then all other bands are our of tune, as i found it our myself.Best is to leave top capacitor on 3.55mhz.. Then you have rest of antenna allmoust correct !. Now to lower swr of this antenna you MUST make wire wich goes thru 4 counterpoise for 40+10m SAGGY !! IT MUST HANG LIKE ITS GONNA FALL OFF..Every band you can lower swr, BUT its posible that oHm wont be in 50oHm.so its compromise. When new ,this antenna wont make problems,but when old you must replace wires with connectors with new one, but remember same size !!!! and solder contacts on it! I did to mine last year after 20+years and it works like charm. Now last part,i use 75ohm 20m coax and my radios give fulle power an all bands, oor use 50ohm coax, but make onder antenna 5-6 turns of coacs round pvc pipe +.10cm dia..That works for me. Now 60-70watts get you round world with this antenna so enjoy it and be lucky you have it. And for missing 80m band, take 2meter steal pipe, beat it in ground, and connect 2m of wire. Then take 40m wire and yust trow it over your house. Then make 4:1balun with T200 thorroid and you have good 80m dipole. Job done ! Good dx to all and hear you on the band. ON3JB
gAPT TITAN dx seemed to work ok on 6 meters this morning, tuned by the internal tuner of my Yaesu FTDX10!
Further experiments to do.
Made FT8 contact 50 miles on 6 mtrs.
Mike
K4QET