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160m loop experiment a big failure

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KD8NNU

160m loop experiment a big failure

I set up a 160m loop in the yard to try one out from all the great
reading I did regarding the antenna.

For me I can get it to tune with no problems except the RF in the shack
is terrible.

I ran 450 ohm ladder line from the antenna to my balanced line
connections on my MFJ 962 d tuner.

As soon as I connect the ladder line the RF is bad, basically everyone
states that I sound like I am in a jet airplane.

Now there is also a bit more to the story as the loop surrounds the
house as that is how the trees are plus the dipole is also very close to
one of the edges on the inside of the loop.

So I dont know if the problem is that everything is in the middle of the
loop, or running ladder line into the shack is a bad thing, maybe the
tuner internal balun is not the correct one.

Bottom line is the K3 was real unhappy with this scenario so the ladder
line is pulled out of the shack and coiled up on the tree next to the
loop outside.

One thing I have researched this morning is that I need a current balun
and I should have it external to the shack and run coax between it and
the shack. Also I should have the shield grounded like I do with the
dipole to direct ground.

So I thought I would share my current failure while I ponder my next
move or give up on the loop. Ok I wont give up, YET!

Cheers

~73
Don
KD8NNU

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Guy, K2AV

Re: 160m loop experiment a big failure

Normally, the field of an antennas diminishes as one goes toward the shack
and (usually) away from the antenna. Your situation makes every conductor
in your shack (and your house) *heavily* coupled. If you want a fight to
the death on making a station work in a heavy RF field, you will probably
emerge as an expert in your field sometime in the future, as the reality of
making that happen in such an extreme situation will tolerate no
half-solutions, no old wive's fixes, and no electronic myths, no
ham-reflector tales. *And* you will have to plug *every* hole on the way
there. Maybe taking K9YC's stuff to another level... He would enjoy
working with you on that.

Your experience, if successful, in the end would make a useful and very good
book.

There are *easier* ways to get a signal on 160 :>)

>From back in my AT&T days, and telco offices in the main field of 50K
broadcast stations, there are a lot of very counter-intuitive things we had
to do in the office I was involved with. In some cases using frame "ground"
as "ground" made things a lot worse. "Dirt" certainly was no savior there.
Each equipment bay had to be evaluated on a case by case basis, and the
negative power leads had to be balanced with positive and UN-grounded
negative bypassed to each other to keep from rectifying RF in the power feed
circuitry.

I suspect there were some Bell Labs guys who came away with brain damage on
that project. "What NOW?" was the word of the day.

73, Guy.

On Sat, Oct 15, 2011 at 12:14 PM, <[hidden email]> wrote:

> I set up a 160m loop in the yard to try one out from all the great
> reading I did regarding the antenna.
>
> For me I can get it to tune with no problems except the RF in the shack
> is terrible.
>
> I ran 450 ohm ladder line from the antenna to my balanced line
> connections on my MFJ 962 d tuner.
>
> As soon as I connect the ladder line the RF is bad, basically everyone
> states that I sound like I am in a jet airplane.
>
> Now there is also a bit more to the story as the loop surrounds the
> house as that is how the trees are plus the dipole is also very close to
> one of the edges on the inside of the loop.
>
> So I dont know if the problem is that everything is in the middle of the
> loop, or running ladder line into the shack is a bad thing, maybe the
> tuner internal balun is not the correct one.
>
> Bottom line is the K3 was real unhappy with this scenario so the ladder
> line is pulled out of the shack and coiled up on the tree next to the
> loop outside.
>
> One thing I have researched this morning is that I need a current balun
> and I should have it external to the shack and run coax between it and
> the shack. Also I should have the shield grounded like I do with the
> dipole to direct ground.
>
> So I thought I would share my current failure while I ponder my next
> move or give up on the loop. Ok I wont give up, YET!
>
> Cheers
>
> ~73
> Don
> KD8NNU
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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N5GE

Re: 160m loop experiment a big failure

In reply to this post by KD8NNU

How high is the loop? If a loop is too close to the ground it will be an NVIS
antenna and send your RF straight up into the clouds.

Use coax, not ladder line. A properly sized loop is supposed to have near a 50
ohm match if fed from a corner.

Yes, you will definitely need a choke balun.

73,
Tom
Amateur Radio Operator N5GE
ARRL Lifetime Member
QCWA Lifetime Member

On Sat, 15 Oct 2011 12:14:31 -0400 (EDT), [hidden email] wrote:

>I set up a 160m loop in the yard to try one out from all the great
>reading I did regarding the antenna.
>
>For me I can get it to tune with no problems except the RF in the shack
>is terrible.
>
>I ran 450 ohm ladder line from the antenna to my balanced line
>connections on my MFJ 962 d tuner.
>
>As soon as I connect the ladder line the RF is bad, basically everyone
>states that I sound like I am in a jet airplane.
>
>Now there is also a bit more to the story as the loop surrounds the
>house as that is how the trees are plus the dipole is also very close to
>one of the edges on the inside of the loop.
>
>So I dont know if the problem is that everything is in the middle of the
>loop, or running ladder line into the shack is a bad thing, maybe the
>tuner internal balun is not the correct one.
>
>Bottom line is the K3 was real unhappy with this scenario so the ladder
>line is pulled out of the shack and coiled up on the tree next to the
>loop outside.
>
>One thing I have researched this morning is that I need a current balun
>and I should have it external to the shack and run coax between it and
>the shack. Also I should have the shield grounded like I do with the
>dipole to direct ground.
>
>So I thought I would share my current failure while I ponder my next
>move or give up on the loop. Ok I wont give up, YET!
>
>Cheers
>
>~73
>Don
>KD8NNU
>
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html

Amateur Radio Operator N5GE

Don Wilhelm-4

Re: 160m loop experiment a big failure

In reply to this post by KD8NNU

Since the loop surrounds your house, you have put the house (and shack)
directly into the highest RF Field for that antenna.

If your house provides good shielding - metal roof and a metal mesh
shield for the siding, with every piece of metal bonded together, you
are going to have a lot of direct RF in the shack just from the antenna
field.

How much power are you attempting to run. You may get away with QRP
levels, but at higher power, you should expect problems.

I suggest first doing an RF Emissions Safety study to determine just how
much radiation you are getting at the house location, and protect
yourself and your family as a first order of business.
If you cannot move the antenna to another location, perhaps you can get
it higher which might help a bit.

I just looked at one of L B Cebik (SK) modeling studies for a 1
wavelength diameter horizontal loop, and if it is 0.15 wavelength above
the ground (80 feet at 160 meters) the radiation is a maximum at 52
degrees from the plane of the loop. At lesser heights, the maximum
radiation will be closer to perpendicular to the plane of the loop.
That does place your shack directly in a high RF Field.

73,
Don W3FPR

On 10/15/2011 12:14 PM, [hidden email] wrote:

Rick WA6NHC

Re: 160m loop experiment a big failure

In reply to this post by N5GE

Small correction: If SINGLE BAND use ONLY, use coax. If multiband, use
window or ladder line (coax is too lossy and can't handle the current and
voltages effectively, over time, for multiband).

[A properly cut loop will be ~50 ohm resonant. Using 300/450/600 ohm feed
will cause a mismatch unless transformed at both ends (lossy). Using 50/75
ohm feed is more efficient in that case. If multiband, ladder line is more
appropriate since most of the bands will not be resonant and a tuner is
required to adapt to the specific load, coax becomes WAY too lossy.]

In EITHER case, use a current based common mode choke (DX Engineering has a
nice paper on this topic in plain simple language, they also sell parts).

If single band use only, a common mode choke at the antenna feed is
appropriate (coax fed). If multiband, use a choke at/near the tuner (open
wire fed).

If you're asking the internal tuner to tune ladder line connected to a
single band antenna, you're already at the limits of the tuner because of
the mismatch you've created (6/9/12:1 depending on feedline). Again, if
single band only, use RG-6 or RG-213 (75 or 50 ohm coax). If multiband,
it's WELL beyond the limits of the internal tuner.

It isn't always possible to make everything 'earth ground' potential (upper
story room, too far from plumbing or ground rod for examples). In that
case, putting everything at the same potential (common bonding) in the shack
is a good choice. Earth ground is 'nice' but often doesn't help for noise
or RFI (though it is required by codes).

If simply connecting the antenna causes RFI then you have a serious problem.
Merely connecting an unused antenna should never cause any changes. In that
case, it's time to check HOW the antennas are switched/connected.

Not knowing what your space limitations are, you might consider making a
physically smaller, coil based antenna for 160 that is farther from the
house. Another option is one of the smaller 'magnetic loop' antennas (with
the advantage that it is rotatable offset by cost).

It has been my experience that if RF wants to bother any electronics or
cause RFI, that it's most likely going to happen on 160.

Putting yourself in the middle of that RF field might not be the best health
choice for you either, regulations or not.

Good luck, you have a big challenge,

Rick WA6NHC

-----Original Message-----
From: n5ge

How high is the loop? If a loop is too close to the ground it will be an
NVIS antenna and send your RF straight up into the clouds.

Use coax, not ladder line. A properly sized loop is supposed to have near a
50 ohm match if fed from a corner.

Yes, you will definitely need a choke balun.

73,
Tom
Amateur Radio Operator N5GE
ARRL Lifetime Member
QCWA Lifetime Member

On Sat, 15 Oct 2011 12:14:31 -0400 (EDT), [hidden email] wrote:

>I set up a 160m loop in the yard to try one out from all the great
>reading I did regarding the antenna.
>
>For me I can get it to tune with no problems except the RF in the shack
>is terrible.
>
>I ran 450 ohm ladder line from the antenna to my balanced line
>connections on my MFJ 962 d tuner.
>
>As soon as I connect the ladder line the RF is bad, basically everyone
>states that I sound like I am in a jet airplane.
>
>Now there is also a bit more to the story as the loop surrounds the
>house as that is how the trees are plus the dipole is also very close to
>one of the edges on the inside of the loop.
>
>So I dont know if the problem is that everything is in the middle of the
>loop, or running ladder line into the shack is a bad thing, maybe the
>tuner internal balun is not the correct one.
>
>Bottom line is the K3 was real unhappy with this scenario so the ladder
>line is pulled out of the shack and coiled up on the tree next to the
>loop outside.
>
>One thing I have researched this morning is that I need a current balun
>and I should have it external to the shack and run coax between it and
>the shack. Also I should have the shield grounded like I do with the
>dipole to direct ground.
>
>So I thought I would share my current failure while I ponder my next
>move or give up on the loop. Ok I wont give up, YET!
>
>Cheers
>
>~73
>Don
>KD8NNU

KD8NNU

Re: 160m loop experiment a big failure

In reply to this post by KD8NNU

Based on all my research today it is apparent that the loop as put up
will have to come down.

As Don points out, I dont want to be in the middle of the microwave. I
just never thought about this other than the nice layout of trees.

Basically I will be pulling it down and use some of my trees and then
have to put two poles up for two corners.

Plus it is clear since I want to use it on multiple bands that I will
have to get a 4:1 current balun.

At least the radio warned me that I was making a microwave by all the RF
in the shack.

I am not as smart on this stuff as I thought I was, as I did research on
the loop and length and so on, but never figured the effect on being in
the middle.

But my dipole works just fine and I will continue to be on the air.

Thanks
Don

~73
Don
KD8NNU

On Sat, Oct 15, 2011 at 2:41 PM, Don Wilhelm wrote:

> Since the loop surrounds your house, you have put the house (and
> shack) directly into the highest RF Field for that antenna.
>
> If your house provides good shielding - metal roof and a metal mesh
> shield for the siding, with every piece of metal bonded together, you
> are going to have a lot of direct RF in the shack just from the
> antenna field.
>
> How much power are you attempting to run. You may get away with QRP
> levels, but at higher power, you should expect problems.
>
> I suggest first doing an RF Emissions Safety study to determine just
> how much radiation you are getting at the house location, and protect
> yourself and your family as a first order of business.
> If you cannot move the antenna to another location, perhaps you can
> get it higher which might help a bit.
>
> I just looked at one of L B Cebik (SK) modeling studies for a 1
> wavelength diameter horizontal loop, and if it is 0.15 wavelength
> above the ground (80 feet at 160 meters) the radiation is a maximum at
> 52 degrees from the plane of the loop. At lesser heights, the maximum
> radiation will be closer to perpendicular to the plane of the loop.
> That does place your shack directly in a high RF Field.
>
> 73,
> Don W3FPR
>
>
>
> On 10/15/2011 12:14 PM, [hidden email] wrote:
>> I set up a 160m loop in the yard to try one out from all the great
>> reading I did regarding the antenna.
>>
>> For me I can get it to tune with no problems except the RF in the
>> shack
>> is terrible.
>>
>> I ran 450 ohm ladder line from the antenna to my balanced line
>> connections on my MFJ 962 d tuner.
>>
>> As soon as I connect the ladder line the RF is bad, basically
>> everyone
>> states that I sound like I am in a jet airplane.
>>
>> Now there is also a bit more to the story as the loop surrounds the
>> house as that is how the trees are plus the dipole is also very close
>> to
>> one of the edges on the inside of the loop.
>>
>> So I dont know if the problem is that everything is in the middle of
>> the
>> loop, or running ladder line into the shack is a bad thing, maybe the
>> tuner internal balun is not the correct one.
>>
>> Bottom line is the K3 was real unhappy with this scenario so the
>> ladder
>> line is pulled out of the shack and coiled up on the tree next to the
>> loop outside.
>>
>> One thing I have researched this morning is that I need a current
>> balun
>> and I should have it external to the shack and run coax between it
>> and
>> the shack. Also I should have the shield grounded like I do with the
>> dipole to direct ground.
>>
>> So I thought I would share my current failure while I ponder my next
>> move or give up on the loop. Ok I wont give up, YET!
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

w0mu

Re: 160m loop experiment a big failure

If it is a horizontal loop it better be pretty high or else all your
signals are going to heat the clouds and worms. try an inverted L or
some type of shortened dipole of V if you need to be on 160.

Mike W0MU

J6/W0MU November 21 - December 1 2011 CQ WW DX CW
W0MU-1 CC Cluster w0mu.net

On 10/15/2011 4:00 PM, [hidden email] wrote:

> Based on all my research today it is apparent that the loop as put up
> will have to come down.
>
> As Don points out, I dont want to be in the middle of the microwave. I
> just never thought about this other than the nice layout of trees.
>
> Basically I will be pulling it down and use some of my trees and then
> have to put two poles up for two corners.
>
> Plus it is clear since I want to use it on multiple bands that I will
> have to get a 4:1 current balun.
>
> At least the radio warned me that I was making a microwave by all the RF
> in the shack.
>
> I am not as smart on this stuff as I thought I was, as I did research on
> the loop and length and so on, but never figured the effect on being in
> the middle.
>
> But my dipole works just fine and I will continue to be on the air.
>
> Thanks
> Don
>
>
> ~73
> Don
> KD8NNU
>
>
> On Sat, Oct 15, 2011 at 2:41 PM, Don Wilhelm wrote:
>
>> Since the loop surrounds your house, you have put the house (and
>> shack) directly into the highest RF Field for that antenna.
>>
>> If your house provides good shielding - metal roof and a metal mesh
>> shield for the siding, with every piece of metal bonded together, you
>> are going to have a lot of direct RF in the shack just from the
>> antenna field.
>>
>> How much power are you attempting to run. You may get away with QRP
>> levels, but at higher power, you should expect problems.
>>
>> I suggest first doing an RF Emissions Safety study to determine just
>> how much radiation you are getting at the house location, and protect
>> yourself and your family as a first order of business.
>> If you cannot move the antenna to another location, perhaps you can
>> get it higher which might help a bit.
>>
>> I just looked at one of L B Cebik (SK) modeling studies for a 1
>> wavelength diameter horizontal loop, and if it is 0.15 wavelength
>> above the ground (80 feet at 160 meters) the radiation is a maximum at
>> 52 degrees from the plane of the loop. At lesser heights, the maximum
>> radiation will be closer to perpendicular to the plane of the loop.
>> That does place your shack directly in a high RF Field.
>>
>> 73,
>> Don W3FPR
>>
>>
>>
>> On 10/15/2011 12:14 PM, [hidden email] wrote:
>>> I set up a 160m loop in the yard to try one out from all the great
>>> reading I did regarding the antenna.
>>>
>>> For me I can get it to tune with no problems except the RF in the
>>> shack
>>> is terrible.
>>>
>>> I ran 450 ohm ladder line from the antenna to my balanced line
>>> connections on my MFJ 962 d tuner.
>>>
>>> As soon as I connect the ladder line the RF is bad, basically
>>> everyone
>>> states that I sound like I am in a jet airplane.
>>>
>>> Now there is also a bit more to the story as the loop surrounds the
>>> house as that is how the trees are plus the dipole is also very close
>>> to
>>> one of the edges on the inside of the loop.
>>>
>>> So I dont know if the problem is that everything is in the middle of
>>> the
>>> loop, or running ladder line into the shack is a bad thing, maybe the
>>> tuner internal balun is not the correct one.
>>>
>>> Bottom line is the K3 was real unhappy with this scenario so the
>>> ladder
>>> line is pulled out of the shack and coiled up on the tree next to the
>>> loop outside.
>>>
>>> One thing I have researched this morning is that I need a current
>>> balun
>>> and I should have it external to the shack and run coax between it
>>> and
>>> the shack. Also I should have the shield grounded like I do with the
>>> dipole to direct ground.
>>>
>>> So I thought I would share my current failure while I ponder my next
>>> move or give up on the loop. Ok I wont give up, YET!
>>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

k6dgw

Re: 160m loop experiment a big failure

In reply to this post by KD8NNU

On 10/15/2011 4:14 PM, [hidden email] wrote:
> So I dont know if the problem is that everything is in the middle of the
> loop, or running ladder line into the shack is a bad thing, maybe the
> tuner internal balun is not the correct one.
The answers are Yes, Yes, and possibly but it probably doesn't matter
given the first two. I gave up on balanced line anywhere near the house
many years ago, nothing seems to tame it. Shack in the middle of the
loop pretty much makes everything in your shack coupled to the antenna.
What the E-field doesn't get, the H-field will. Just basically a
difficult situation to engineer.
> One thing I have researched this morning is that I need a current balun
> and I should have it external to the shack and run coax between it and
> the shack. Also I should have the shield grounded like I do with the
> dipole to direct ground.
I doubt it will make a huge difference, and you need a huge difference
in this config, but it's antennas, they're magic and ferrites over your
coax are cheep ... worth a try. Getting the balanced line out of the
house should make a big difference. Everything that is part of your rig
or connected to it should be grounded to a single point, also tied to
the safety ground [green wire, often the bare wire in the utility
sockets] of your mains. Be careful about multiple connections to
"earth," there are serious safety considerations here.
> So I thought I would share my current failure while I ponder my next
> move or give up on the loop. Ok I wont give up, YET!
I'd try it with the coax balun outside, maybe run as close to the ground
as possible [under it would be best, on it a second choice, but not
elevated where it can become an unwanted receiving antenna for your own
signal, unless of course you are seeking to talk to yourself. :-) You
can also try winding your coax a few times through a ferrite core or two
right before it enters the house. Jim, K9YC, is an expert here:
audiosystemsgroup.com/publish.htm

Good Luck,

Fred K6DGW
Auburn CA

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k1htv

Re: 160m loop experiment a big failure

In reply to this post by KD8NNU

Don,
How did you plan to use the 160M loop? If you want to work the locals (within
500 miles) a low (less than 100 ft high) 160M loop is a great sky warmer. If you
are more interested in working DX on the Topband then give an Inverted-L a try.

I've had very good luck with two that I've built. The one that favors Europe,
Africa, the Caribbean and So. America has only 30 feet of the 135 feet of wire
vertical. The rest of it is horizontal, ending up around 50 feet high in a tree.
This Inverted-L is fed with 50 Ohm coax with a 500pf capacitor in series at the
base of the antenna. Presently there are 16 short (1/8 wavelength, 65 ft)
radials. The second Inverted-L has 60 ft. of vertical with the rest horizontal,
sloping down to 30 feet. This antenna favors the west and northwest. It has 8
quarter wave, 130 feet, radials.

Running the K3 barefoot with these Inverted-L antennas, since I've moved to my
new VA QTH, I've increased my Topband DXCC total from 201 to 222 countries
confirmed running 100 Watts or less. Some of the best DX to the east includes
4X, S0, 5N, D4 and UA6. To the south CE, CX, VP8/F and to the west FO,
FO/A,T30,T2,KH6,ZL & a number of KL7's to the NW. So, as you can see the
Inverted-L, even without a lot of the wire being vertical, can perform well as a
DX antenna. It certainly will outperform a 160M loop.

So, if you are interested in making longer haul QSOs on 160M, I would ditch the
loop and go with an Inverted-L. If you have a tower, I would shunt feed it, but
that's another story.

73,
Rich - K1HTV

= = =

-----Original Message-----
From: [hidden email] [mailto:[hidden email]]
Sent: Saturday, October 15, 2011 12:15 PM
To: Elecraft
Subject: [Elecraft] 160m loop experiment a big failure

I set up a 160m loop in the yard to try one out from all the great reading I did
regarding the antenna.

For me I can get it to tune with no problems except the RF in the shack is
terrible.
.
.
.
.
So I thought I would share my current failure while I ponder my next
move or give up on the loop. Ok I wont give up, YET!

Cheers

~73
Don
KD8NNU

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Post: mailto:[hidden email]

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Jon Kåre Hellan

Re: 160m loop experiment a big failure

On 10/17/2011 03:02 PM, Rich - K1HTV wrote:
> Don,
> How did you plan to use the 160M loop? If you want to work the locals (within
> 500 miles) a low (less than 100 ft high) 160M loop is a great sky warmer. If you
> are more interested in working DX on the Topband then give an Inverted-L a try.

Up to a point, this is true. Given that a loop is possible, you can also
make an inverted L, and it would work better for DX. A double L may also
be a good choice. See
http://www.surriel.com/radio/160-meter-double-l-antenna.

But sky warmers can do very well, too. I don't have trees taller than 4m
(13'). My lot is abt 600 sq m (0.15 acres). This is actually considered
large in Europe. There is almost, but not quite, room for a dipole for
80m. To get on the lower bands, I started out with an inv vee, slightly
shortened, 15m (45') at the apex and 4-5m (15') up at the ends. I built
it for a local sweepstakes like contest, but worked 80m DXCC with it.
(Easier from Europe than from the USA.) Last winter, I wanted to play
with 160m, and ran low wire to the ends of the inv vee. Seen from above,
the antenna looks rather like a 'Z'. Result after one season: 61
countries, including Canada, USA and Tajikistan.

It helps that outside my local area of abt 200k inhabitants, population
is pretty sparse for 3-400 km or so. There is also no AM broadcasting.
This makes QRM arriving from high angles less of a problem than it would
be in much of the USA.

I'm not arguing that you should build a skywarmer where a low angle
antenna is feasible. But it would be a shame not to try *something*, if
you can't put up an ideal antenna.

73
Jon LA4RT

>
> I've had very good luck with two that I've built. The one that favors Europe,
> Africa, the Caribbean and So. America has only 30 feet of the 135 feet of wire
> vertical. The rest of it is horizontal, ending up around 50 feet high in a tree.
> This Inverted-L is fed with 50 Ohm coax with a 500pf capacitor in series at the
> base of the antenna. Presently there are 16 short (1/8 wavelength, 65 ft)
> radials. The second Inverted-L has 60 ft. of vertical with the rest horizontal,
> sloping down to 30 feet. This antenna favors the west and northwest. It has 8
> quarter wave, 130 feet, radials.
>
> Running the K3 barefoot with these Inverted-L antennas, since I've moved to my
> new VA QTH, I've increased my Topband DXCC total from 201 to 222 countries
> confirmed running 100 Watts or less. Some of the best DX to the east includes
> 4X, S0, 5N, D4 and UA6. To the south CE, CX, VP8/F and to the west FO,
> FO/A,T30,T2,KH6,ZL& a number of KL7's to the NW. So, as you can see the
> Inverted-L, even without a lot of the wire being vertical, can perform well as a
> DX antenna. It certainly will outperform a 160M loop.
>
> So, if you are interested in making longer haul QSOs on 160M, I would ditch the
> loop and go with an Inverted-L. If you have a tower, I would shunt feed it, but
> that's another story.
>
> 73,
> Rich - K1HTV
>
> = = =
>
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]]
> Sent: Saturday, October 15, 2011 12:15 PM
> To: Elecraft
> Subject: [Elecraft] 160m loop experiment a big failure
>
> I set up a 160m loop in the yard to try one out from all the great reading I did
> regarding the antenna.
>
> For me I can get it to tune with no problems except the RF in the shack is
> terrible.
> .
> .
> .
> .
> So I thought I would share my current failure while I ponder my next
> move or give up on the loop. Ok I wont give up, YET!
>
> Cheers
>
> ~73
> Don
> KD8NNU
>
>
>
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Richard Fjeld

Re: 160m loop experiment a big failure

In reply to this post by KD8NNU

Don,

I have been reading this with interest. Just wanted to add a word of support.

I have made two 80 meter loops fed with 450 ohm ladder line. A 160m loop is just larger. I have used a Johnson Viking Matchbox tuner, and one with a roller inductor with them. (I use a MFJ-212 Matchmaker to tune the tuner w/o putting any carrier out, unless I want to verify that it is properly tuned)

I fed both loops at a corner, and both were excellent. I still use one. I had no RFI with either one. HOWEVER, NEITHER LOOPS CIRCLED THE HOUSE.

The length of your feedline is very important. For 160m, avoid lengths around 120, or 240 feet. There are preferred lengths also.

>From what I read, it is important to keep the antenna and feedline balanced so that the currents on the feedline are equal and opposite. Keep the feedline several inches away from anything metallic. The same goes for the antenna. Keep the feedline leads evenly spaced apart. As for your tuner, don't forget to place the short grounding jumper needed for most tuners when using twin-lead.

Hang in there,

Dick, n0ce

(I copied and pasted an excerpt of this to keep it short)

On Sat, 15 Oct 2011 12:14:31 -0400 (EDT), [hidden email] wrote:

>I set up a 160m loop in the yard to try one out from all the great
>reading I did regarding the antenna.
>
>For me I can get it to tune with no problems except the RF in the shack
>is terrible.
>
>I ran 450 ohm ladder line from the antenna to my balanced line
>connections on my MFJ 962 d tuner. (and so forth.)

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Steve Walter WA3A

Re: 160m loop experiment a big failure

In reply to this post by KD8NNU

I use only open-wire fed antennas here. I have 3 feedlines that come right into the shack to balanced tuners (Palstar BT1500A) and run the legal limit with few RFI problems. My house is in the middle of a large rhombic (unterminated) antenna. I don't have a station ground other than the AC safety ground at my shack.
My shack is in the basement but Ive had this same setup on the second floor with good results. IMO, an outside ground thats brought to the 2nd floor is not needed and in fact will cause problems. If I had any coax feeds I would follow the SPG design for lightning protection but with open wire I have disconnects where they enter the house and ALWAYS disconnect and ground them (common ground to AC entrance) about 20' from the house.
A balanced tuner will help a lot.
Open-wire feedline probably isnt the cause of your RFI.
It sounds like you may be on to something with your latest post.
73, Steve

Tony Estep

Re: 160m loop experiment a big failure

On Fri, Oct 21, 2011 at 8:06 AM, Steve Walter WA3A <[hidden email]> wrote:

> ....IMO, an outside ground thats brought to the 2nd floor is
> not needed and in fact will cause problems....

=========
Don, I think that Steve's comment above may be on the right track. First
things first: cobble up a good star-system for tying everything together
with short fat wire or strapping to get all the chassis at the same RF
potential. Then kill off the common mode currents that run on the outside of
your coax; I've had great luck with RF isolators from
http://www.radioworks.com/ct-4.html I have one between K3 and amp, and
another between my tuner and the balun that goes to my antenna system. I
have a simple counterpoise system from the second-floor window to the garage
roof, and that connects to the cold side of the balun. It is also where the
outside grounding system connects. If there are still some strays, you can
use snap-on ferrites, but I have found in a couple of different
installations that once the common-mode currents on the coax are dealt with,
there aren't any further RF problems. Steve also mentions that his shack is
in the middle of a rhombic antenna, which suggests that your loop
arrangement may work fine once you get the shack setup tamed.

73 and good luck,
Tony KT0NY

--
http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352
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W8JH

Re: 160m loop experiment a big failure

In reply to this post by Steve Walter WA3A

I have an 80m horizontal loop which is above and encircles my house. It is fed with 600 ohm ladder line which I bring into the basement shack and use a Palstar BT 1500 tuner. With the tuner I use it on 6m-80m. The loop is only broken where it enters the house to an ICE ground which is attached to a ground rod and to the service ground. I also have no RF problems even after adding the KPA-500 to the mix. K3, KPA-500, Palstar and computer all grounded and tied to service ground.

The house is made of 9" thick exterior walls and 14" thick roof. Both made of a steel exterior frame and steel interior frame which is fully filled with styrofoam. Basically panels made with steel studs inside and out. I have no idea if that helps with RFI or not but it does help with utility bills!

73,

Joe, W8JH
K3 1713, KPA 132

73,

Joe, W8JH

K3s, KPA 500, KAT 500 and KX3 happy user.