Re: Topband: 160m Vertical matching Help

Rick, what are the ball park figured on the coil diameter I'm guessing 5 or so inches across is a good place to start Paul. N0AH Sent with AquaMail for Android http://www.aqua-mail.com On November 1, 2017 11:25:42 AM "Richard (Rick) Karlquist" wrote: > You need

Re: Topband: 160m Vertical matching Help

a drawing guys would help Sent with AquaMail for Android http://www.aqua-mail.com On November 1, 2017 12:28:35 PM MR TREVOR DUNNE wrote: > Thanks everyone for the replies, I'm new to all this so you may go easy on > me, I don't understand this R+JX stuff so I need a

Re: Topband: 160m Vertical matching Help

Hi guys Before anything else, don't trust MFJ269 reading, transmit with 10 w and measure the SWR. It is very common the energy from AM broadcast stations changes the real impedance reading on portable analyzers. 73's N4IS JC -Original Message- From: Topband

Topband: 160m Vertical matching Help

Hi Trevor Read Joe, W4TV's answer again ! The coil should be whatever inductance you need to resonate your slightly short antenna . . . then you can use that coil as an auto-transformer to get a good match, ie once the antenna is resonant, you can feed your coax a few turns up the coil. But

Re: Topband: 160m Vertical matching Help

Trevol, the portion of the coil between the tap and the base of the vertical determines resonance and needs to be variable unless you were lucky and found the correct value. The shunt portion of the coil affects the feed impedance. This shunt portion is like the hairpin match for a yagi. You

Re: Topband: 160m Vertical matching Help

Thanks everyone for the replies, I'm new to all this so you may go easy on me, I don't understand this R+JX stuff so I need a dummies guide if possible, I have the vertical section at the top of the coil and I connect the feed line to it where I can get the lowest SWR at 1.825mhz, Does the

Re: Topband: 160m Vertical matching Help

Start by disconnecting the feedline. Connect a jumper to the junction of the vertical wire and the coil. Now use a grid dip meter and tap down the coil until the antenna is resonant (dip occurs) at the desired frequency. Now connect the feed line (shield to ground) and tap up the coil until

Re: Topband: 160m Vertical matching Help

Trevor, You haven't really provided enough information to solve your problem.  If you want to use a shunt coil then I suggest that you consider measuring the R-jX at your frequency of interest and then designing an L-network using purposeful shortening of the antenna to create a capacitive

Re: Topband: 160m Vertical matching Help

You need +j34 ohms in parallel with your coax coming in. This is about 3 microhenries. This would be around 6 turns on your coil if the turns are spaced a wire diameter. IOW, tap the coax 6 turns from the grounded end. Then tap the antenna to whatever tunes to 1.83 MHz. Rick N6RK On 11/1/2017

Re: Topband: 160m Vertical matching Help

Hi Wes Thanks for the reply I can move the point of lowest SWR by moving the tap on the coil, I need to lower the SWR I thought using the coil across the feed point would do this but its not working for me?? Thanks Trevor EI2GLB - Original Message - From: "Wes Attaway (N5WA)"

Re: Topband: 160m Vertical matching Help

Without doing any modeling, an off the top of the head idea, one option would be to drop a wire down from the end of each of the T wires you have at the top. You might be able to move the point of lowest SWR down to 1.8 with 2x 15' +/- drop wires. --- Wes Attaway (N5WA) (318)

Topband: 160m Vertical matching Help

Hi All I finally got the vertical up and running, problem I have now is I can't find a low SWR on the coil, the best I can get is about 2.8:1 no matter where I tap the coil that's the best SWR, I can move that point up and down the band by moving the tap but the SWR stays the same, My