Posted by
Barry LaZar on
Aug 26, 2020; 1:03am
URL: http://elecraft.85.s1.nabble.com/Inverted-L-for-160-meters-tp7664325p7664337.html
Kevin,
Your instincts are right on. But, to answer your question the
radials do not need to be 130' long, but it is better than a shorter
set. The inverted L represents a 1/4 wave over ground and needs the
other half, the radials. But, here is where it gets a little tricky. 5
radials are not enough if they are on the ground, but elevate them and 5
starts to represent a better counterpoise. I have a 132 feet of wire for
an inverted L but, I only go vertical for ~61'. I, too, have only 5
radials and they vary in length to fit my backyard; the horizontal
section of my antenna goes over the house. The antenna does work well on
160-40 meters, and 1/2 the time I use it on 30 and 1/2 the time I use a
20 meter vertical dipole on 30; it's a pattern thing. And, I have only
these two antennas.
I do have a suggestion. That is feed your inverted L with a remote
antenna tuner. This will allow your antenna to be used on other bands
and keep loses low on the transmission line when high SWRs are present,
and they will be. How much loss? that will depend on the feed line you use.
On 8/25/2020 7:58 PM, kevinr wrote:
> Two reasons why I want to use an inverted L. One) it fits my property
> well. Two) I have never tried one before.
>
> I currently have an extra long doublet. I can't remember the exact
> length but seem to remember over 120 feet for each leg. The tuner on
> my K3 just won't match it below 2:1.0 so I don't want to transmit on
> it. It hears well enough but just won't match.
>
> Reason number two pushes me onward :)
>
> 73, Kevin. KD5ONS
>
>
> On 8/25/20 4:49 PM, Lyn Norstad wrote:
>> Good gracious. Why does everyone overthink 160m? OK, maybe just
>> because it's fun. I get that.
>>
>> But as to operation, I have one (1) antenna, and it is a 360 foot EDZ
>> (dipole) cut for 3.5 MHz. It's great on all bands, 160 - 6m. No
>> radials needed.
>>
>> Specifically I worked 47 of the 50 states in one 24 hour period on
>> 160m (holdouts were AK, HI and NV - all picked up within a day or two).
>>
>> I could 'splain more, if anyone is interested.
>>
>> 73
>> Lyn, W0LEN
>>
>>
>>
>> -----Original Message-----
>> From:
[hidden email]
>> [mailto:
[hidden email]] On Behalf Of kevinr
>> Sent: Tuesday, August 25, 2020 6:24 PM
>> To: Elecraft Reflector
>> Subject: [Elecraft] Inverted L for 160 meters
>>
>> From what I can find, and what I can calculate, five wires, each ~130
>> feet long, could make a nice inverted L for 160 meters. One leg for the
>> vertical and horizontal portion of the antenna. Four legs for the
>> counterpoise (ground plane). There are many broken wire antennas stored
>> in my shed which are fodder for the radials. Do all of the legs for the
>> counterpoise need to be 1/4 wavelength or can I substitute some shorter
>> lengths? The feedpoint should somewhere above 50 ohms impedance. As I
>> add more radials that number will reach 50 ohms asymptotically.
>>
>> I can get the vertical part up to 70 or 80 feet above ground with the
>> rest of it horizontal. Most of the radiation should take place from the
>> vertical part since it is closer to the feed point. But there should be
>> some effect from the direction of the horizontal portion. How strongly
>> does the direction of the horizontal portion effect the radiation
>> pattern of the antenna system? My property allows me to point it from
>> 300 degrees around to 200 degrees so I have plenty of options. Between
>> 200 and 300 degrees there is a road used by loggers, and the folks
>> maintaining the towers at the top of this mountain. They can break any
>> antenna lower than 80 feet above ground. Spar poles and cranes clear
>> out any dead limbs across the road.
>>
>> Inquiring minds...
>>
>> Kevin. KD5ONS
>>
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