I have an inverted L and using a hairpin coil to match in on 160M. One coil is 6 inches OD the other is 2 inches OD. I have been thinking about making another hairpin with wire wrapped around a toroi
I am sorry, I left this out, the Hairpin is inserted between the inverted L and ground / ground radials. coils were tapped for best match, in my case about 27 ohms is the best I can do. -- Jim K9TF _
Jim, That is not how the hairpin should work. You should resonate your antenna at say 1.900mhz then add the hairpin across the feedpoint to bring it to resonance at your operating frequency say 1.830
Hi, Jim I don't see why the "hairpin" matching coil should be adding BCI. The inverted L above it should be picking much more broadcast signal than the coil! Sounds like your matching coil may have e
A hairpin or a parallel matching inductor should be adjusted this way: 1. select inductance (hairpin length); 2. adjust wire length for the desired resonant frequency. Repeat 1 and 2 until you get SW
To amplify a little on some other comments - For an Inv L, and a decent radial system, with a coil shorted across (shunt) the vertical wire input to the braid/radials, the otherwise low impedance can
Has any one used the MFJ-907 and do what I am trying to do on 160M as a hairpin match? what range. My 6 inch coil with remote tuner in line with the tap on 160m I am getting around a Q of 80. My 2 in
MFJ and Texas Instrument used this type of calculation for antenna Q. The other attachment is what some other people are using with their inverted using the K2AV balun and a Gamma match on bands othe
I didn't read everything in this thread, but there's a good alternative to a matching coil. On my 160m inverted-L, I just use two air variable capacitors, and they work great. One adjusts the impedan
Hi Jim, A gamma match is an arm extending out or up on the element from the "ground" point. It is named "gamma" because it looks like the capital Greek letter called "gamma". See http://en.wikipedia.
Ok, I found the photos, and I see that I need to take new ones of the present arrangement. But here's the capacitor values in the L network. - Between the 75 ohm coax center cond. and antenna: 350 pF
Should work just fine, Mike, since your inverted L is > 1/4 wavelength and has some series inductive reactance. You're tuning out a portion of that series inductance, leaving the remainder to work wi
Great! I like the spark gap and the 33K static drain much better between the antenna and ground, that between the antenna and radials as in your first post! I was thinking of sending you a note to th
The thing works, I mean the shunt match works. what would be a good Q for just the coil? 300, 600, 900 Operating Q, what is the desired value? Whats your formula for that? Q of the operating antenna,
Hello, Jim You seem to be "lost"! First of all, the "thing" that you originally called a "hairpin match" is NOT a "shunt match". The coil, or "hairpin" is in SERIES with the reactance and radiation r
Sorry, I just looked at my own post and I see that the reflector or e-mail changed my superscripts to lower case. The formula is Q(squared) +1 or Q*2 +1 Sorry, Charlie, K4OTV --Original Message-- Fro
Hi Jim, I'm glad to hear you (and others) liked our L-network inverted-L tuner design. All the info I have is posted in the Topband thread. I thought I had more info and pictures, but I guess I'll ha