Topband: inverted-L

[N4ZR]

Thanks to everyone who responded to my message - lots of good ideas.  I 
think my favorite was the one about tapping a shunt coil from both ends, 
alternately, to bring both the radiation resistance and the resonant 
frequency in line.


--

73, Pete N4ZR
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Topband: Hairpin match to inverted L?

[john]

A hairpin works great on non-OWA Yagi's so why not use it on a  
vertical?  I used a THHN primitively made hairpin coil on my P40A 160m  
vertical and it really made the transmitter happy. You will have to  
shorten the vertical length slightly after adding the hairpin.  DX  
Engineering makes a match but I have no experience with it:  
https://www.dxengineering.com/parts/dxe-vmn-1


John KK9A


N4ZR wrote:

The other day a ham friend suggested using a coil ("hairpin") to match
the low impedance of a well-radialed inverted L to 50-ohm coax.  This
struck me as a potentially-attractive alternative to a series vacuum
capacitor, but I don't know enough to evaluate it. Thoughts?

--

73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Hairpin match to inverted L?

[Mark - N5OT]

Plastic bottles are the coil form of choice on DXpeditions.  Excellent.

Mark N5OT


On 9/3/2019 5:55 AM, ly...@qrz.lt wrote:

Hi Pete,

Here is picture of coil I made to tune Inv. L at 9Y4 with 15-20 Ohm impedance. 
It was tuned in 2 steps:

1. calculate and wound coil to rise R close to 50 Ohm
2. adjust horizontal wire length back to desired freq.

https://photos.app.goo.gl/7eVBt5t8yCAvsaZg7

Used thin wire for coil, not sure if it is right or not, used what I had there.

73
Arunas LY2ij /LY5E



2019 m. rugsėjo 1 d., 21:47 val., "N4ZR"  parašė:


The other day a ham friend suggested using a coil ("hairpin") to match
the low impedance of a well-radialed inverted L to 50-ohm coax.  This
struck me as a potentially-attractive alternative to a series vacuum
capacitor, but I don't know enough to evaluate it. Thoughts?

--

73, Pete N4ZR

_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector


_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Hairpin match to inverted L?

[ly2ij]

Hi Pete,

Here is picture of coil I made to tune Inv. L at 9Y4 with 15-20 Ohm impedance. 
It was tuned in 2 steps:

1. calculate and wound coil to rise R close to 50 Ohm
2. adjust horizontal wire length back to desired freq.

https://photos.app.goo.gl/7eVBt5t8yCAvsaZg7

Used thin wire for coil, not sure if it is right or not, used what I had there.

73
Arunas LY2ij /LY5E



2019 m. rugsėjo 1 d., 21:47 val., "N4ZR"  parašė:

> The other day a ham friend suggested using a coil ("hairpin") to match 
> the low impedance of a well-radialed inverted L to 50-ohm coax.  This 
> struck me as a potentially-attractive alternative to a series vacuum 
> capacitor, but I don't know enough to evaluate it. Thoughts?
> 
> -- 
> 
> 73, Pete N4ZR
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector