On 10/14/2012 8:16 PM, tom wrote:
On 10/14/2012 7:48 PM, gipy wrote:
On Sunday, October 14, 2012 7:55:14 PM UTC-4, tom wrote:
On 10/14/2012 6:02 PM, gipy wrote:

Wow, a newsgroup cop and an English teacher!

BTW it's I'm and not I'M, but I won't tell you to learn the language
you write.

I very much respect and appreciate the "first person's" opinion and my
apologies to him for not expressing that before but it is just that,
an opinion, just like mine. I did not think a difference of opinion
could be called an argument.

My disagreement "not argument" really had little to do with my
question about burying the feed-line, not which antenna works best.

I am pretty sure by now this thread has gone south thanks to your
watchful eye on correctness, sensitivity and diplomacy on this group
but anyway,
I would still like to hear from anyone with some advice on burying a
feed-line.


No. not a newsgroup cop, just wondering why the first response to you
was disputed. And I held the cap key down too long. It happens.

He's pretty much on the nose though in his comments. If you can make a
G5RV or random work, it's mostly luck. Yes, with end fed proper
grounding helps a lot, but it's still a crap shoot.

tom
K0TAR
Hi tom,

I have been a ham since 1955. I have experience trying different types
of antennas. At one point (10 years) I designed antenna installations
for Raytheon Co.

Those who have not compared their random wire or G5RV to a good antenna
figure it is working just fine.

I can say that I know that if you want a dipole to work on multiple
bands, it needs to be a full 1/2 wavelength on the band you want it to
work on. Feeding it with open wire and a tuner will allow some decent
performance on bands that are higher in frequency. I am guessing Tom
that you already know this.

My favourite antenna for living in the city on a lot surrounded by homes
and industry is the horizontal loop fed with open wire. This does a
great job of nulling horizontal noise from the town.

Many hams just look at the 102 foot spec for a G5RV and works all bands
and say great. If they can talk to anyone they figure it must be
perfect. It is not actually a bad antenna on 20 meters. However, the
performance on 75 is abysmal. I work 75 most of the time and when I hear
a new guy come on in our area with a weak signal we all figure the guy
is running a G5RV. This is usually the case. We always nudge him in the
direction of putting up a decent antenna.

The only time a random wire makes any sense is aboard ship or boats. If
you can make a solid connection to the sea water you have a decent
antenna. BTW a decent connection on a non steel or aluminum vessel is 30
square feet of copper plate on the outside of the hull.

It is hardly worth my time to talk with anyone who already figures he
knows all about antennas because he has used a G5RV and it works fine.
We need to reserve our comments about what really works for those who
are actually interested in improving their station operation and have
not taken the attitude that they are already experts. :-)

There is a guy here my age who has experimented with antennas much more
than have I. He nudged me into changing my 450 plastic dialectrict
balanced line to my loop to an open wire. I did not expect much
difference. I was shocked at the improvement. He is our resident expert
in the "North Woods". This is the Michigan upper peninsula, Northern
Wisconsin, and Minnesota. He is not an expert on antenna theory or math,
but damn sure knows what works best. I wish I had changed my feed line
three years ago when he told me to do so.

Michael

On Monday, October 15, 2012 9:38:37 AM UTC-4, RipeCrisbies wrote:
On Mon, 15 Oct 2012 08:28:57 +0100, Ian Jackson wrote:



it would normally be better to locate the tuner at the far

end - although this would entail having a longer run of coax.



And make it an inverted L while you're at it! I'm just about to order an

SGC239 auto ATU for my inverted L (www.radiowymsey.org/invl.htm). My coax

lies on the ground but only because half the garden is patio and steps.







Charlie.



--

M0WYM

www.radiowymsey.org



Sales @ radiowymsey

http://stores.ebay.co.uk/Sales-At-Radio-Wymsey/

I am in a situation where I HAVE to bury the feedline, there is no other way around it. I have trees about 20 feet away from my home in the back, great for swinging a long wire, dipole, whatever works but being that the actual space between the trees and my home is a common area, I have to bury the coax.
Placing a remote tuner on the other side would be a bit of a hassle but I see its starting to look like the only way to go?
I got plenty of time, I just want to do this once and the right way.
Again, any thoughts appreciated and thanks to all who have posted, it is turning out to be a very interesting thread.

"gipy" wrote in message
...
I am in a situation where I HAVE to bury the feedline, there is no other
way around it. I have trees about 20 feet away from my home in the back,
great for swinging a long wire, dipole, whatever works but being that the
actual space between the trees and my home is a common area, I have to
bury the coax.
Placing a remote tuner on the other side would be a bit of a hassle but I
see its starting to look like the only way to go?
I got plenty of time, I just want to do this once and the right way.

It looks like you will have to use either a remote tuner, or something you
can feed with coax. Maybe a trap type of dipole.
While I have no idea how they would work, you may want to check out some
from DXS Engineering.
http://www.dxengineering.com/search/department/antennas

For some of the low bands I use a homade OCF antenna patterned after the
Carolina Windom. But I also have other antennas up for some of the bands.
..

On Monday, October 15, 2012 2:59:37 PM UTC-5, Boomer wrote:
(A G5RV) is not actually a bad antenna on 20 meters. However, the
performance on 75 is abysmal.

Would you please itemize the losses and radiation patterns that explain why you believe that to be true for 75m?
--
73, Cecil, w5dxp.com

On 10/15/2012 2:59 PM, Boomer wrote:

There is a guy here my age who has experimented with antennas much more
than have I. He nudged me into changing my 450 plastic dialectrict
balanced line to my loop to an open wire. I did not expect much
difference. I was shocked at the improvement. He is our resident expert
in the "North Woods". This is the Michigan upper peninsula, Northern
Wisconsin, and Minnesota. He is not an expert on antenna theory or math,
but damn sure knows what works best. I wish I had changed my feed line
three years ago when he told me to do so.

Michael

Live in the Minneapolis metro and just got back from the lower peninsula
last Monday. Was camping next to the lake in West Olive. Used my usual
portable HF antenna, a 20m end fed. I also have a 40/20 end fed, but
didn't figure it was worth the trouble for this trip since I was going
to be busy with other things at the site and I didn't know the campground.

You probably know the rule here - if you put it up at 20 below it will
never come down.

tom
K0TAR

On 10/15/2012 7:46 PM, tom wrote:


You probably know the rule here - if you put it up at 20 below it will
never come down.

Sorry, context - the rule in the upper Midwest.

tom
K0TAR

On 10/15/2012 6:42 PM, W5DXP wrote:
On Monday, October 15, 2012 2:59:37 PM UTC-5, Boomer wrote:
(A G5RV) is not actually a bad antenna on 20 meters. However, the
performance on 75 is abysmal.

Would you please itemize the losses and radiation patterns that explain why you believe that to be true for 75m?
--
73, Cecil, w5dxp.com

I don't have any of the math for you. However, I know what works and
what does not. You probably do not listen to your own G5RV. Its poor
performance is pretty clear to anyone who listens to you. However, if
you have an emotional bond with your G5RV, I would not want to be the
cause of any alienation in your relationship. Keep using it. The low
effective radiation makes for more band space for the rest of us. The
signal just disappears into the noise level.

Better yet just put up a random wire and a water pipe for ground. You
can get a perfect match with a tuner. It will work better than the long
wire the guy wanted to bury in the ground :-) In fact I recommend you
try burying your G5RV and make a stealth G5RV. It will still load with a
good tuner.

However, if you were actually interested in improving your transmitted
and received signal, you might tune around 75 and listen to those
stations putting out a big signal. Especially in the daytime when band
conditions are bad. Ask someone with that big signal what antenna they
are using. If they are using a G5RV then you are right and I am wrong.

Michael

In message , Boomer
writes
On 10/15/2012 6:42 PM, W5DXP wrote:
On Monday, October 15, 2012 2:59:37 PM UTC-5, Boomer wrote:
(A G5RV) is not actually a bad antenna on 20 meters. However, the
performance on 75 is abysmal.

Would you please itemize the losses and radiation patterns that
explain why you believe that to be true for 75m?
--
73, Cecil, w5dxp.com

I don't have any of the math for you. However, I know what works and
what does not. You probably do not listen to your own G5RV. Its poor
performance is pretty clear to anyone who listens to you. However, if
you have an emotional bond with your G5RV, I would not want to be the
cause of any alienation in your relationship. Keep using it. The low
effective radiation makes for more band space for the rest of us. The
signal just disappears into the noise level.

Better yet just put up a random wire and a water pipe for ground. You
can get a perfect match with a tuner. It will work better than the long
wire the guy wanted to bury in the ground :-) In fact I recommend you
try burying your G5RV and make a stealth G5RV. It will still load with
a good tuner.

However, if you were actually interested in improving your transmitted
and received signal, you might tune around 75 and listen to those
stations putting out a big signal. Especially in the daytime when band
conditions are bad. Ask someone with that big signal what antenna they
are using. If they are using a G5RV then you are right and I am wrong.

I doubt if many will choose to use a G5RV when they can put up a
'better' antenna, and it's unlikely that the stations putting out really
big signals are using one. However, subject to an appreciation of its
characteristics and limitations, it can usually be made to perform
reasonably well.

Regarding the use of shorter-than-halfwave dipoles, the following
writings of W8JI (and the included links) are worth a read.
http://www.w8ji.com/short_dipoles_and_problems.htm

I've had a quick look, and it seems that the main cause of poor
efficiency/performance is that as the dipole is progressively shortened,
the increasingly high SWR causes high losses on the feeder. Cunningly
minimise the SWR, and you can still have a reasonably efficient
radiator.

It may also be useful to look at one of G4FGQ's programs - 'Dipole3'. If
you enter zero feeder lengths, this gives a quick assessment of the
efficiency of the dipole alone.
http://www.zerobeat.net/G4FGQ/page3.html
http://www.zerobeat.net/G4FGQ/dipole3.exe
--
Ian

On Tuesday, October 16, 2012 10:54:02 AM UTC-5, Boomer wrote:
I don't have any of the (G5RV) math for you.

Allow me to provide it based on EZNEC simulations and VK1OD's transmission line loss calculator. The G5RV will be compared to a 127 foot coax-fed dipole, both at a height of 40 feet and both antenna systems resonant at 3.72 MHz.

The 127 foot dipole has a maximum gain of 6.42 dBi at TOA of 90 degrees.
The G5RV dipole has a maximum gain of 6.06 dBi at TOA of 90 degrees.

The 127 foot dipole has a gain of 4.65 dBi at an elevation angle of 45 degrees.
The G5RV has a gain of 4.37 dBi at an elevation angle of 45 degrees.
The dipole beats the G5RV by 0.28dB

The 127 foot dipole has a resonant feedpoint impedance of 59 ohms at 3.72 MHz.
The G5RV has a feedpoint impedance of 33-j355 ohms at 3.72 MHz.

For 30' of RG-213, the 127' dipole has 0.093dB loss.
For 30' of 300 ohm twinlead, the G5RV has 0.89dB loss.
The 127' dipole beats the G5RV by 0.8dB

For another 50' of RG-213, the 127' dipole has 0.175dB loss.
For 50' of RG-213, the G5RV has 0.241dB loss.
The 127' dipole beats the G5RV by 0.066dB

The 127' dipole beats the G5RV by 1.15dB which is 20% of one S-unit. Human ears can barely detect a 1dB change.

So please explain to us how one signal that is 1.15dB lower than a second signal can "disappear into the noise level" and why your ears are so much better than the ears of normal homo sapiens.

Some hams think that -1.15dB on 75m (20% of one S-unit) is a rational compromise for an antenna that also works well as is on 40m, 20m, and 12m.
--
73, Cecil, w5dxp.com

On Tuesday, October 16, 2012 11:54:02 AM UTC-4, Boomer wrote:
On 10/15/2012 6:42 PM, W5DXP wrote:

On Monday, October 15, 2012 2:59:37 PM UTC-5, Boomer wrote:

(A G5RV) is not actually a bad antenna on 20 meters. However, the

performance on 75 is abysmal.



Would you please itemize the losses and radiation patterns that explain why you believe that to be true for 75m?

--

73, Cecil, w5dxp.com



I don't have any of the math for you. However, I know what works and

what does not. You probably do not listen to your own G5RV. Its poor

performance is pretty clear to anyone who listens to you. However, if

you have an emotional bond with your G5RV, I would not want to be the

cause of any alienation in your relationship. Keep using it. The low

effective radiation makes for more band space for the rest of us. The

signal just disappears into the noise level.



Better yet just put up a random wire and a water pipe for ground. You

can get a perfect match with a tuner. It will work better than the long

wire the guy wanted to bury in the ground :-) In fact I recommend you

try burying your G5RV and make a stealth G5RV. It will still load with a

good tuner.



However, if you were actually interested in improving your transmitted

and received signal, you might tune around 75 and listen to those

stations putting out a big signal. Especially in the daytime when band

conditions are bad. Ask someone with that big signal what antenna they

are using. If they are using a G5RV then you are right and I am wrong.



Michael

Random wire and water pipe was what got me hooked. Now I have lots of land behind my home for a real nice long wire but I cant get the wire across to my property