Re: Topband: 160 m inverted L

om> Sent: Wednesday, November 09, 2016 4:57 PM Subject: Re: Topband: 160 m inverted L Think of a dipole close to the ground, it will not be efficient with all that coupling to earth and resulting losses. 73 Peter -Original Message- From: Topband [mailto:topband-boun...@contesting.com

Re: Topband: 160 m inverted L

Got a lot of mail about this, teaching me to shut up because I don't have much free time. Look folks, as you all know, just about everything with antennas works in some fashion and there's a sliding scale. It's not all black and white. With elevated radials, it isn't as if putting radials at 20

Re: Topband: 160 m inverted L

ontesting.com> Sent: Wednesday, November 09, 2016 4:57 PM Subject: Re: Topband: 160 m inverted L Think of a dipole close to the ground, it will not be efficient with all that coupling to earth and resulting losses. 73 Peter -Original Message- From: Topband [mailto:topband-boun...@con

Re: Topband: 160 m inverted L

Atkinson; topband Subject: Re: Topband: 160 m inverted L I recall reading from Ralph Holland that 0.015 wavelength was a good height. David G3UNA - Original Message - From: "Mike Waters" <mikew...@gmail.com> To: "Rob Atkinson" <ranchoro...@gmail.com>; &q

Re: Topband: 160 m inverted L

nt: Wednesday, November 09, 2016 4:11 PM Subject: Re: Topband: 160 m inverted L Fifty feet?! That means the feedpoint --the bottom of the antenna-- would be 50 feet up! Do you know how high the top would have to be? I don't agree with that at all. And I've never heard of anyone who ever did that

Re: Topband: 160 M Inverted 'L'

Here are some photos of the omega match (L-network) tuner I was referring to earlier. No inductor needed. Visit www.w0btu.com/files/antenna/160m_inv-L and click on 100_3761.JPG there. As I said, that tuner (1) easily handled the full legal limit and (2) the bigger capacitor there was overkill.

Re: Topband: 160 m inverted L

m inverted L thanks Rob, The best I can do in my situation is 10 feet high for the 160M elevated radials. A far cry from 50 feet :-( I will work on maximizing the size of my ground screen under the inverted L. Hopefully this will increase some of the efficiency lost from the low elevated

Re: Topband: 160 m inverted L

Fifty feet?! That means the feedpoint --the bottom of the antenna-- would be 50 feet up! Do you know how high the top would have to be? I don't agree with that at all. And I've never heard of anyone who ever did that. The four elevated radials in these tests were just 16 feet high! And what is

Topband: 160 M Inverted 'L'

Folks, You don’t need expensive vacuum capacitors or bread slicers/toast racks to match your 160 metre ‘L’. I use a low pass L-network consisting of 0.95 microhenrys in series and 1600 pF in parallel with the coax. The inductor is not real and is made by slightly extending the length of the

Re: Topband: 160 m inverted L

Agree. I use three fixed serial caps with shorting relays to tune my 160m T, 8 elevated 125' radials, across the full band in 45KHz segments. The antenna is cut for 1820 and fed with a 50::25 TLT. The voltages across each cap (3 all the same value) is well below 400v at QRO so I used

Re: Topband: 160 m inverted L

Makes sense Rob. Probably a good approach is to find the capacitance needed and use fixed vacuum caps in lieu of a vacuum variable. Then we have a bullet proof feed sys. Fixed vac caps are plentiful on ebay. I have collected a bunch of them. What height would be adequate for a 160 elevated

Re: Topband: 160 m inverted L

I fully agree. And wide plate spacing isn't either, even at the legal limit! I used an omega match (with two capacitors and no inductors) to match the coax to my 160m inverted-L. The largest one in the photo on my site is overkill, it's what I had. 73, Mike www.w0btu.com On Nov 8, 2016 4:55 PM,

Re: Topband: 160 m inverted L

I’ve never owned a vacuum variable. What I have been using for decades are very large air variables hung from a stick, or tree or whatever and I cover it up with a 2L pop bottle* with the bottom cut out of it. Fix in place with rope, string, tape, fishing line, whatever. I can’t take credit for

Re: Topband: 160 m inverted L

From: Herbert Schoenbohm <he...@vitelcom.net> To: topband@contesting.com Sent: Tuesday, November 8, 2016 5:12 PM Subject: Re: Topband: 160 m inverted L Bread slicers have their issues and are not really the best solution.  Herb, I must agree with you. Over 25 years ago, I

Re: Topband: 160 m inverted L

Bread slicers have their issues and are not really the best solution. Using a fixed high current mica G2 broadcast capacitor of a higher value than you need, and making it variable with a series inductor is the way to go. This is what broadcast stations do in their ATU's. I haven't ever

Re: Topband: 160 m inverted L

A vacuum variable for L impedance matching is unnecessary. Vacuum variable capacitors leak eventually. It take a long time for them to go through their ranges and you have to have the mechanics outside if you perform remote tuning, to sense or count turns to track when the v.v. is nearing its

Re: Topband: 160 m inverted L

On Tue, Nov 8, 2016 at 12:23 PM, Rob Atkinson wrote: > I have no idea what a "FCP" is, but it doesn't matter. > > 1. An inverted L is an _unbalanced_ antenna. Therefore you don't need a > balun. > An FCP is a Folded Counterpoise. Basically, it's an elevated radial for

Re: Topband: 160 m inverted L

I have no idea what a "FCP" is, but it doesn't matter. 1. An inverted L is an _unbalanced_ antenna. Therefore you don't need a balun. 2. This means you can feed it with unbalanced line, i.e. coax. 3. You can use an unbalanced matching network such as an L network, preferably at the feedpoint.

Re: Topband: 160 m inverted L

l Message- > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Art Heft > Sent: Monday, November 07, 2016 3:06 PM > To: topband@contesting.com > Subject: Topband: 160 m inverted L > > I finally got the inverted L up this afternoon. Vertical dimension is 65' >

Re: Topband: 160 m inverted L

--- > > -Original Message- > From: Topband [mailto:topband-boun...@contesting.com <javascript:;>] On > Behalf Of Art Heft > Sent: Monday, November 07, 2016 3:06 PM > To: topband@contesting.com <javascript:;> > Subject: Topband: 160 m inverted L > > I f

Re: Topband: 160 m inverted L

, LA Computer/Cellphone Forensics AttawayForensics.com --- -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Art Heft Sent: Monday, November 07, 2016 3:06 PM To: topband@contesting.com Subject: Topband: 160 m inverted L I finally got

Re: Topband: 160 m inverted L

Hi Art, Don't know whether you are measuring L to FCP with nothing else connected or measuring shack side of isolation transformer. You should be measuring on shack side of transformer, with L and FCP connected. A feed R of 1000 sounds way, way far off. A feed R of 40-50-60-70-80 would be

Topband: 160 m inverted L

I finally got the inverted L up this afternoon. Vertical dimension is 65' and the almost horizontal dimension is 95'. I am using a very carefully built FCP and the commercial transformer. My SARK 110 shows resonance at about 1.68 MHz but the resistive part is up around 1000 ohms. Taken right