KM6SQB
| Joined: | Fri, May 4th 2018, 11:28 | Roles: | N/A | Moderates: | N/A |
Latest Topics
| Topic | Created | Posts | Views | Last Activity |
|---|---|---|---|---|
| "wacky"? SWR readings on tuning antennae.. Help?? | Dec 2nd 2018, 18:36 | 3 | 6,569 | on 3/12/18 |
| adjusting SWR and hamsticks - help?? | Nov 3rd 2018, 12:07 | 11 | 18,132 | on 10/10/20 |
Latest Posts
| Topic | Author | Posted On |
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| "wacky"? SWR readings on tuning antennae.. Help?? | KM6SQB | on 2/12/18 |
| Hi All, just got general license few months ago, and antennae tuning has me going in circles. Brierfly, have Yaesu 450 D and purchased 2- 20 meter hamsticks PLUS dipole assembly from MFJ. Tuned both sticks separately to about 1.2, when attached both to dipole mount, the SWR reading went up and resonant frequency decreased! SWR readings are different when comparing readings from 6 ft RG8X coax connected to ant analyzer, to reading with the 50 ft run from antennae to actual radio, Funny thing too, if I leave out the whip on one hamstick, and insert whip in other(depth in fiberglass base about 1.5 inches), SWR reads about 6 @ 13.7 Mhz, and SOMETIMES the int tuner can tune in the 20 meter band(lowest point, of course).When I insert whip further into the fiberglass base, SWR jumps to 7 around 14.7 Mhz, just moving whip a few mm)!! I cannot fathom what is going on. Tried isolator/ 1:1 balun, and results no better. Any wisdom from your greater wisdom/knowledge than me in this situation would be much obliged!!! Sometimes wondering about getting mobile mag mount, obtaining as big a metal cookie sheet as possible(using as ground/radial??? and seeing how that goes. Saw Youtube video on a ham who did this, but he also put out 4 radials from the mount base, but don't know how he calculated the radial length. thanks in advance!! Harry KM6 SQB |
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| adjusting SWR and hamsticks - help?? | KM6SQB | on 4/11/18 |
| thanks for your replies; if you don't mind a few more "silly" or self-evident questions? As I read, even though the SWR may read 3:1 or higher, if auto antennae tuner can find solution and tune it, then may assume that SWR is probably 1.5:1 or less and good to go? Yes, RE hamstick dipole, one end has fiberglass alone(no whip), and other end has whip inserted into fiberglass about 7" too, so will definitely cut the excess internal whip to avoid heat injury. Re resonant frequency, how do you find it? my SWR measures of course, SWR and power only, no frequency, and what I did was find a midpoint in the 20 meter band and then with each few second transmission, would move the whip further in or out of the fiberglass portion to find the best ratio. Also, to make sure I did it right, I put the transceiver at around 25 watts am, then moved the SWR to full deflection, then put it in mode to measure SWR. Is this correct? or should I put out the full 100 watts, then the SWR meter would show full deflection(and then some), but that would artificially cause a higher SWR reading when I place the meter in SWR reading mode(I found that out couple days ago), and the MFJ SWR instructions said nothing RE the amt of emitted power needed as long as full scale deflection showed. thanks again all!!! Harry KM6 SQB (Huntington Beach, CA) |
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| adjusting SWR and hamsticks - help?? | KM6SQB | on 3/11/18 |
| Hi all, just got my general 2 months ago! Have Yaesu 450 D and trying to tune MFJ 20 meter hamsticks. Have dipole setup(2 sticks), and unable to tune with BOTH whips inserted into fiberglass portion! When I leave one whip out, other inserted about 6" into fiberglass, SWR reads just over 1.5:1, and Yaesu int ant tuner tunes it! Results go contrary to what I believe hamstck dipoles should do. Also, when I install a 1:1 balun on ant coax, the int Yaesu tuner will NOT tune, but with balun removed from line, the int ant tuner tunes easily. I am a pediatrician, and just like trying to figure out why a child is not gaining weight normally, this has got my neurons going in circles!! Any help would be much obliged! thanks in advance!! | ||
