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More antenna problems

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Wingkeel

RE: More antenna problems

Terry

I am using a hy-gain vertical (6BTV) and also have a random length of wire.
Both have given me contacts in the US and decent DX - 4X, XE, LU, TI2, TG,
etc. It sounds to me like you are picking up a lot of just plain old "line"
noise, that is, dimmers, florescent lights and the cursed switching power
supply used in most PCs.

My wire is a length of RG-58, about 50 feet, running to the edge of the
house at ground level, there the shield is grounded to an 8 foot ground rod.
For static drain I have a 100 uh inductor across the center and ground at
this point, like is added on the KPA-100 mod. I then took 70 ft of copper
wire, Radio Shack SWL antenna wire, went straight up the house to the peak
(about 18 feet) and then over to the highest tree that I could get a rock
through one of the branches (about 40 feet high and 40 feet away. The wire
is not tight and sort of makes a sagging arch about like a quarter circle.
But it works almost as good as the Hy-Gain and the K2 has no problem tuning
it on any band. WWV comes through on 15 at 10 to 20 over in the late
afternoon early evenings.

You might want to make sure that you have set L34 at its optimum point as
the noise will affect the AGC in addition to giving you extra noise. A
technique I stumbled on follows.

Follow the instructions for "I.F. Amplifier Alignment." When you get to the
last step plug the PC sound card into the Speaker Jack (not Headphone as it
attenuates some high frequencies). You will notice some noise spread across
the Spectrogram display. Make sure the XFIL is set for FL-1
OP-1. Now continue to adjust L34 for a compromise of the lowest displayed
noise and the highest level of the tone. You will find a point where the
noise is almost non existent. If you don't have Spectrogram just about any
PSK program will also work - I found the waterfall mode gave a sort of
"Sonar" display that was obvious when all of the "grass" (noise) was gone.

Follow the instructions for setting the AGC (do that after above even if you
thought it was set properly.

Even though I had adjusted this to what I thought was the best by "ear,"
after using this method and then re-adjusting the ARC threshold. I was
amazed at the difference in sensitivity and audio level. Maybe this is one
of the problems/reasons you have "low output volume," "high noise," or "low
gain."

Rich
KE0X

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Jim Brown-10

Re: More antenna problems

In reply to this post by Wingkeel

On Tue, 27 Jul 2004 09:35:15 EDT, [hidden email] wrote:

>I'm seriously thinking about buying as 5-band Hustler to ground mount behind
>my shack. I've been told that my signal to noise ratio would improve
>considerab

Congratulations on your upgrade and getting on the air. I seriously doubt that a
vertical antenna would help your noise situation -- in general, noise tends to be
vertically polarized, and a vertical would make matters worse. The salesman is
not giving you good advice, either because of ignorance or because he wants to
sell you an antenna.

I live in the middle of Chicago, and have problems with noise too, but maybe not
as bad as yours. I have several antennas here, and find that some pick up less
noise than others. Three are horizontal, two are vertical. The location of these
antennas and how close they happen to be to the noise sources has a lot to do
with how much noise they pick up.

You didn't say what bands you are trying to operate. If you can do it, I would try to
put up a horizontal half-wave dipole for the band(s) you want to work. Multi-band
trap dipoles work fine, and the traps allow them to be shorter than full-size half-
wave dipoles. The HyPower Antenna company makes very nice loading coil
traps and will sell you the traps only or complete antennas. I've built two antennas
using their loading coil traps. Do a google search to find them. Barry is very
good to deal with.

If your space is limited, I would concentrate on bands that allow you to use
shorter antennas. 20 m and 30 m are excellent bands for QRP and the antennas
don't have to be very long to be reasonably effective. At my qth, I also find that the
bands get less noisy as I go higher in frequency.

Another idea for you. If you have one of those VHF talkies that lets you listen to
the HF bands, try taking it around your home and surrounding area to listen for
the noise you hear on your main HF rig. This may give you some ideas about
where an antenna will pick up less noise, and it can also tell you which of your
home electronics gear may be generating that noise! Computers, digital
equipment, TV's, etc. are notorious for generating RF noise.

73,

Jim K9YC

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Leigh L. Klotz Jr WA5ZNU

Re: More antenna problems

Administrator

In reply to this post by Wingkeel

Here are some suggestions:

1. Read Cebik's articles on antennas (google search for cebik antenna).
Then decide about your lengths and feeding arrangement and see if it
still makes sense in your site.

2. Try turning off all the circuit breakers in your house and see if the
noise goes away

3. For a noise test, try a cheap 20m vertical yourself -- run a wire
straight up 16-17ft and then run two or three more a foot or more off
the ground -- the them to plastic chairs if need be -- and try that
hooked to your rig temporarily outside and see what it is like.
73,
WA5ZNU Leigh
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Laurie Landry

Re: More antenna problems

In reply to this post by Jim Brown-10

May I add to the home electronic apparatus that generate noise:touch lamps
or whatever the proper name is.

VE1AWJ

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Vic K2VCO

Re: More antenna problems

In reply to this post by Wingkeel

[hidden email] wrote:

> My antenna is a 100' length of wire fed by 50' of RG8X Mini. The
> feed point is at 10' off the ground through a balun.

This doesn't have anything to do with your noise problem, but you should
realize that you probably have a relatively high SWR on the feedline and
balun on most bands, even though the KAT2 reduces the SWR seen by the K2
to a manageable level. As a result, loss in the coax and balun is quite
high (the balun is worthless in this situation, and probably
significantly reduces performance). I know you say that you get out
well, but believe me you would get out better with a resonant antenna or
one fed with ladder line.

> There is a power line at the same height as the balun just over the
> property line, (about 12' away). The noise blanker has no
> appreciable effect on noise, so I doubt if power line noise is having
> much effect.

Power lines conduct noise from devices connnected to them, and from
actual faults (cracked or dirty insulators, etc.) on the line. 12' is
very close. Your noise could be coming from someone's pump half a mile
away or a fluorescent light in your kitchen, etc. Some kinds of noise
are reduced by the NB, others not.

My suggestion is to replace your antenna with a 40-meter dipole or a
multiband dipole (using either traps or parallel elements for each
band). The antenna should be resonant on the bands on which you plan to
operate. If you feed it with coax, use a 1-1 balun at the feedpoint.
If you use ladder-line, use a 4-1 balun at the entry to the house, and
then run 50-ohm coax to the K2. Try to locate the antenna as far as
possible from the power line, and (most important) oriented at 90
degrees to it. The balanced line or isolated coax line will then reduce
pickup of noise by the feedline itself.

This system will have minimal noise pickup and maximize efficiency,
important for QRP operation.

> I'm seriously thinking about buying as 5-band Hustler to ground mount behind
> my shack. I've been told that my signal to noise ratio would improve
> considerably by a salesman at a local store. He suggested either the Cushman or the
> Hustler and indicated that for the $350 difference, the Hustler receives almost
> as good as the Cushman.

A vertical antenna will probably pick up MORE noise than a horizontal
one, since local manmade noise appears to be primarily vertically
polarized (I'm not sure why this is so, but it is). In addition, if you
can get the horizontal wire up to about 30' at the center, it will
perform much better than the vertical for most QSOs. If you do get the
Hustler, make sure you have a good radial system (either elevated or
in-ground) -- without it, it will be a dummy load. An acceptable in- or
on- ground radial system for this kind of antenna (40 m and up) can be
constructed of 16 20' radials; an elevated system should have 2 resonant
radials for each band that you intend to work. I think you would get
much better results at lest cost with the horizontal system I've outlined.

I know I've touched on a number of religious issues in this post, but so
be it.

--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco

My K2 also has the KAT2 which matches up at 1.3:1 on

> 40-meters. My power supply is an Anstron SS30 which is about 4' away
> from the radio. The power supply has no effect on a computer about
> the same distance away. The noise seems to be white in nature and not
> the 60-cycle hum. Periodically, the noise will fluctuate about 2
> s-units which I attribute to scatter effect.
>
> Several people have indicated that I have busted through pileups with
> 10-watts out. Others have indicated that I had the strongest signal
> out there at times...Usually in Utah and Texas. I live in Boulder,
> CO.
>
> My problem is that I cannot hear the incoming signals very well
> through the 5-7 S-units of noise between 1830-2100 when I can get on
> the radio. I just completed realigning my receiver with the
> Spectrogram software.
>
> I have not been able to work anything outside of the US since I
> finished my K2 and got my General license about 4-weeks ago. I also
> cannot work anything or anybody between 0500-1830. Sometimes I can
> find a weak signal but I can never get back to them on 5-10 Watts.
> Is this the norm for this cycle?
>
> I'm seriously thinking about buying as 5-band Hustler to ground mount
> behind my shack. I've been told that my signal to noise ratio would
> improve considerably by a salesman at a local store. He suggested
> either the Cushman or the Hustler and indicated that for the $350
> difference, the Hustler receives almost as good as the Cushman. Any
> thoughts? I'm getting pretty desperate. I can use all the Morse
> Code programs in the world but it all gets boring after about
> 5-minutes, otherwise, I can talk for hours to real people! For a
> newcomer, its kind of like fishing...you never know what you've got
> till you bring it in. One of the most fun aspects is looking them up
> in the ARRL database to get an address to send a QSL card to. At 54,
> I thought I'd done it all...LIFE IS GOOD!
>
> Thanks all
>
> 73 de Terry - KC0QZX _______________________________________________
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Phil, WB6TQG

RE: More antenna problems

In reply to this post by Wingkeel

Hi Terry,

> My antenna is a 100' length of wire fed by 50' of RG8X Mini.
> The feed point is at 10' off the ground through a balun.
> The wire arches up to about 25' in the tallest tree on our
> lot and the wire points roughly south. The backside is a
> 60' length of 12 GA insulated wire thrown over the roof, (my
> property line is less than 10' behind the feed point).
> There is a power line at the same height as the balun just
> over the property line, (about 12' away).

My background noise was terrible when my antenna was a few feet above the
roof of the house. Every TV and computer monitor came blasting through on 20
meters. Moving it away from the house greatly reduced the RFI. I would also
expect the power line to radiate RFI from all of the noisy loads that it
feeds.

Depending on the layout of your property, is it possible to put up a dipole
(best) or inverted-vee? Keep it as far as possible from the power line and
house, and if possible aim the ends towards the powerline to reduce pickup
from it.

> My power supply is an Anstron SS30 which is about 4' away from
> the radio. The power supply has no effect on a computer about the
> same distance away.

The K2 is MUCH more sensitive than a computer. I also use an SS30, and can
hear RFI from it on AM broadcast radios in other rooms of the house. I am
not knocking the SS30, you just have to expect switching supplies to
radiate. If the RFI is from the SS30, you will hear the frequency change
when you vary the load current.

It was mentioned in another email that you could use a handheld that covers
the HF bands to look for noise. If you don't have one, an AM broadcast radio
might help.

> I'm seriously thinking about buying as 5-band Hustler to ground
> mount behind my shack. I've been told that my signal to noise
> ratio would improve considerably by a salesman at a local store.

I wouldn't count on it. Before spending money on it, try a wire vertical
(this was suggested in another email). Also keep in mind that verticals
usually need radials.

Keep us posted on this.

73,
Phil, WB6TQG

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Stuart Rohre

Re: More antenna problems

I agree with Phil, that a ground mounted vertical would pick up more
household noise than a horizontal dipole placed away from the house. See
the Cebik web site; www.cebik.com for antenna ideas that really work for
limited space.
72,
Stuart
K5KVH

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Parker Buckley

Re: More antenna problems

In reply to this post by Wingkeel

I've read several responses indicating that verticals are more noise-prone than dipoles, cf zepps, etc. I live on an average city lot with power lines at the back, and my experience has been a little different. I've used a Butternut HF-2V with 16 radials for many years. I've also experimented with a variety of wire antennas, including center fed zepps, dipoles, vertical dipoles fed with ladder line, verticals with elevated radials, verticals with loaded elevated radials (as in Moxon), and consistently the ground mounted vertical monopole is quieter (and provides at least the same signal strength). I've also tried a simple monopole for 30 meters (made from HF-2V parts) mounted on the same ground system, and found it to be quieter than any of the wire antennas on 30, either vertical or horizontal. I believe the ground system is key to the whole thing.....the ground mounted vertical is simply quieter than elevated ones. If you can install a decent set of radials (quite easy to do: mow the grass, stake the wires out, and let Mother Nature hide them for you; at least it works in Ohio), I think a vertical is worth considering. I've done extensive EZNEC modelling of all these antennas, and while interesting and fun, the noise issue is hard to predict and can be one of the more important considerations.

Parker WD8JOL K2 #2636
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George, W5YR

Re: Re: More antenna problems

Parker, what did you think of the EZNEC gain predictions for verticals?
Compared to wire dipoles at a modest height?

73, George W5YR
Fairview, TX
[hidden email]
http://www.w5yr.com

----- Original Message -----
From: "Parker Buckley" <[hidden email]>
To: <[hidden email]>
Sent: Wednesday, July 28, 2004 6:10 AM
Subject: [Elecraft] Re: More antenna problems

I've read several responses indicating that verticals are more noise-prone
than dipoles, cf zepps, etc. I live on an average city lot with power
lines at the back, and my experience has been a little different. I've used
a Butternut HF-2V with 16 radials for many years. I've also experimented
with a variety of wire antennas, including center fed zepps, dipoles,
vertical dipoles fed with ladder line, verticals with elevated radials,
verticals with loaded elevated radials (as in Moxon), and consistently the
ground mounted vertical monopole is quieter (and provides at least the same
signal strength). I've also tried a simple monopole for 30 meters (made
from HF-2V parts) mounted on the same ground system, and found it to be
quieter than any of the wire antennas on 30, either vertical or horizontal.
I believe the ground system is key to the whole thing.....the ground mounted
vertical is simply quieter than elevated ones. If you can install a decent
set of radials (quite easy to do: mow the grass, stake the wires out, and
let Mother Nature hide them for you; at least it works in Ohio), I think a
vertical is worth considering. I've done extensive EZNEC modelling of all
these antennas, and while interesting and fun, the noise issue is hard to
predict and can be one of the more important considerations.

Parker WD8JOL K2 #2636
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Jim Brown-10

Re: Re: More antenna problems

In reply to this post by Parker Buckley

On Wed, 28 Jul 2004 07:10:27 -0400, Parker Buckley wrote:

>I believe the ground system is key to the whole thing.....the ground mounted
>vertical is simply quieter than elevated ones.

You may be right, but I suspect that the location of the antenna with respect to the
noise is more likely the key.

Jim K9YC

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George, W5YR

Re: Re: More antenna problems

Theory supports the vertical being the nosier antenna since soil attenuation
tends to result in most man-made noise being predominately vertically
polarized a few wavelengths beyond the noise source. However, if you have a
really large and effective radial field extending from the antenna to near
the noise source(s), then the polarization shift could be reduced or not
take place at all and the vertical would be no nosier than any other
antenna.

But as Jim points out, noise pickup is like real estate: "location,
location, location!" There are probably as many exceptions as there are
examples.

I know that my Butternut HF-9V is much noisier than my two 20 meter EDZs
(mounted at right angles) or my 80-meter full-wave horizontal low loop. By
the same token, the loop is seldom any quieter than the EDZs despite "common
knowledge" that loops are quieter.

73, George W5YR
Fairview, TX
[hidden email]
http://www.w5yr.com

----- Original Message -----
From: "Jim Brown" <[hidden email]>
To: <[hidden email]>
Sent: Wednesday, July 28, 2004 10:34 AM
Subject: Re: [Elecraft] Re: More antenna problems

> On Wed, 28 Jul 2004 07:10:27 -0400, Parker Buckley wrote:
>
> >I believe the ground system is key to the whole thing.....the ground
mounted
> >vertical is simply quieter than elevated ones.
>
> You may be right, but I suspect that the location of the antenna with
respect to the
> noise is more likely the key.
>
> Jim K9YC

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G3VVT

Re: Re: More antenna problems

In reply to this post by Wingkeel

One of the amateur radio elders in the UK, Dick G2DYM puts forward the
theory that buildings and presumably power lines are surrounded by an envelope of
electronic "smog". To clear this noise you have to have your antenna mounted
above this noise source or presumably if on the ground well clear of these
items. Additionally he is a firm advocate of using balanced feeders to minimise
noise pick on the feeder to the antenna.

Have always lived in locations with substantial amounts of rock under the
top soil, so never could get verticals to work on the ground no matter what I
did. They were just about as good as a vertical piece of wet string! The only
way was to get them mounted as high as possible with four full sized radials
underneath the base of the antenna for each band they were resonant on. With
that you could work the world at the right time.

Bob, G3VVT
K2 #4168
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Ron D'Eau Claire-2

RE: Re: More antenna problems

In reply to this post by Jim Brown-10

The "rule of thumb" is that verticals are noisier because QRN (lightning
crashes, etc.) are generally vertically-polarized. In my experience this is
true on the lower frequency bands (e.g. 160 and 80 meters).

But there are a lot of other types of noise and noise sources. QRN that is
propagated and radiated from power lines - which tend to be horizontal - may
couple much better into a horizontal wire than a vertical, for example.

Like all "rules of thumb", whether or not it is true depends a great deal on
the "thumb", as Jim points out.

Ron AC7AC

-----Original Message-----
On Wed, 28 Jul 2004 07:10:27 -0400, Parker Buckley wrote:

>I believe the ground system is key to the whole thing.....the ground
>mounted
>vertical is simply quieter than elevated ones.

You may be right, but I suspect that the location of the antenna with
respect to the
noise is more likely the key.

Jim K9YC

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Earl W Cunningham

Re: Re: More antenna problems

In reply to this post by Wingkeel

George, W5YR writes:

"Parker, what did you think of the EZNEC gain predictions for verticals?
Compared to wire dipoles at a modest height?"
==========
The free space gain of a vertical is about the same as that of a dipole
(2.14 dBi). However, over real ground the horizontal antenna benefits by
far field ground reflection. This is borne out in EZNEC.

Remember that a vertical's gain is concentrated at the low angles that
are good for DXing, while the horizontal antenna must be relatively high
(at least 0.5 wavelengths) to have a reasonably low angle of radiation..

As far as noise goes, the dipole has a better receive S/N ratio than a
vertical simply because it has directivity, while the vertical is
omnidirectional. Also, because of its low angle radiation, the vertical
"hears" man made noises better (which are generated close to the ground
and therefore arrive at a low angle).

73, de Earl, K6SE
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Parker Buckley

Re: Re: More antenna problems

Earl,

I agree that's what the model shows and what the theory says. You're
probably assuming the dipole is at least a half wave above ground, which can
be a challenge at lower frequencies. I'm just relating my real world
experiences, and suggesting that the vertical not be dismissed too soon in
the considerations.

Would love to continue, but I'm heading out on a trip. Looking forward to
checking back in when I return!

73,
Parker WD8JOL

----- Original Message -----
From: "Earl W Cunningham" <[hidden email]>
To: <[hidden email]>; <[hidden email]>; <[hidden email]>
Sent: Wednesday, July 28, 2004 1:01 PM
Subject: Re: [Elecraft] Re: More antenna problems

> George, W5YR writes:
>
> "Parker, what did you think of the EZNEC gain predictions for verticals?
> Compared to wire dipoles at a modest height?"
> ==========
> The free space gain of a vertical is about the same as that of a dipole
> (2.14 dBi). However, over real ground the horizontal antenna benefits by
> far field ground reflection. This is borne out in EZNEC.
>
> Remember that a vertical's gain is concentrated at the low angles that
> are good for DXing, while the horizontal antenna must be relatively high
> (at least 0.5 wavelengths) to have a reasonably low angle of radiation..
>
> As far as noise goes, the dipole has a better receive S/N ratio than a
> vertical simply because it has directivity, while the vertical is
> omnidirectional. Also, because of its low angle radiation, the vertical
> "hears" man made noises better (which are generated close to the ground
> and therefore arrive at a low angle).
>
> 73, de Earl, K6SE

George, W5YR

Re: Re: More antenna problems

In reply to this post by Earl W Cunningham

I regret that in my Socratic approach. I failed to make the point I was
trying to make. Specifically that while vertical antennas may have a low
takeoff angle their gain is usually less than that of an isotropic antenna.

For example, look at "vert1.ez" in EZNEC and you find that its gain is -0.04
dB max at an elevation angle of about 25 degrees. Similarly, if you look at
"bydipole.ez" on 40 meters you find that although the elevation angle for a
dipole height of 30 ft is near 90 degrees, the gain is over 7 dBi. Raise the
dipole to 67 ft as Earl points out and the gain increases slightly but the
takeoff angle declines to about 30 degrees and the azimuth pattern begins to
form.

So, Earl's points are well made: high dipoles if low-angle radiation is
desired with gain over isotropic or vertical antennas performing essentially
as isotropics but with a low takeoff angle. To me, the trade-off is that if
you take the wire invested in the vertical and the radial field and can
manage to get it up in the air high enough, you obtain significant gain over
isotropic, a low takeoff angle and some degree of azimuthal pattern - which
may or may not be advantageous depending upon the orientation of the antenna
supports.

73, George W5YR
Fairview, TX
[hidden email]
http://www.w5yr.com

----- Original Message -----
From: "Earl W Cunningham" <[hidden email]>
To: <[hidden email]>; <[hidden email]>; <[hidden email]>
Sent: Wednesday, July 28, 2004 12:01 PM
Subject: Re: [Elecraft] Re: More antenna problems

Stuart Rohre

Re: More antenna problems

In reply to this post by Jim Brown-10

Indeed, I agree that a horizontal antenna may be less noisy than the ground
mounted vertical.

You can try a simple wire dipole made of hook up wire at little expense to
check local noise situation and its orientation may make a big difference in
noise. The wire should not be parallel and at same height as any power
wiring.

You might experiment with orientation for desired directions vs. noise
pickup, then make a permanent antenna based on that.

If you do get a ground mounted vertical, you could do what I did with my Gap
Titan, elevate it 6 or 7 feet to walk under radials/ counterpoise, and that
also lessens noise pickup in the Titan case.

Now the Titan does shield the feedline inside the off center feed for
several feet and that may be operating to cut noise, as a waveguide beyond
cutoff filter.
73,
Stuart
K5KVH

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