At a former job we HAD to receive WWV (10 or 15MHZ).
It was winter and icy, so all I was willing to do was "toss"
a wire on our flat roof. We were in the old university gym,
with a large, flat roof. About 100'X200'. I ran the wire
lengthwise. The roof was wood, covered by several
layuers of tar, paper and gravel. The antenna worked
well enough to "get by" but the first day the roof was clear,
I errected a better antenna, by elevating the wire on 10'
EMT sections. It was a difference like night and day.
The only change was the elevation. So, while an antenna
will work laying on the roof, it will work much better up in the
air over that roof. The electric shop was very unhappy to
have to install 2 ~60' wire to 8' ground rods.
Whne we took the antenna down 12 years later, internet
time services made WWV old hat, I scavenged the wire,
ground were and rods and the EMT and fittings. I was told to
remove that "old stuff" and "throw it away". It went into my
car. I used (and still use) the ground rods and heavy copper
ground wire, and still have the antenna wire rolled up. I hope
to errect it after I retire and "move to the country". We bought
the good, heavy hard cooper wire and they paid big bucks to
get it there the next day.

Terry

"Telamon" wrote in message
...
It looks like everyone on this thread has top posted so I will just so
it continues to make sense.

It's good to see that you have finally decided to do it right.

There is no problem laying the wire on the roof as long as it not near
any significantly long conductors. The impedance of the wire will be a
little lower than if it was hanging in mid air. The impedance of the
wire will drop much lower if it and the roof are wet, which will not
present a problem for receiving.

I would not use this as a transmitting antenna. It is a worse situation
when the roof is wet but even dry you are heating your roof with the RF
energy and this could start a fire if enough power is used.

The wire's measured impedance at the opperating frequency was about 100
ohms. 10 watts at 100 ohms gives less than half an amp. I wouldn't be to
concerned on an asphalt roof.

In article ,
"CW" wrote:

You are quite right to question this. I have an antenna wire laying
directly on my roof. It's been there for over ten years and works as
well as the one I have in the back yard that's totally suspended. The
one on the roof is bare wire. I have used it for transmitting where
it also works fine, as long as it's not raining. In wet whether, the
SWR goes nuts but this would not be of any concern for receiving. You
are right about the house electrical wire. Thousands of ham antennas
have been made from it.

"H Davis" wrote in message
...
First, my thanks to Laura for asking a question that guys probably
wouldn't ask anymore than we would ask directions if lost. In both
cases we seem to be satisfied with wandering around.

Also, once again thanks to Joe for a somewhat complete answer to
Laura's question. (I'd love to get Joe over here for a long
conversation and just pick his brain for a few hours.) But I would
like an even more complete answer. Joe and others seem to feel that
you can't just lay a wire on your roof and hold it down somehow and
still get better reception that you get with the whip indoors. I'm
thinking you aren't satisfied with that answer. If you are, I
apologize. I'm not satisfied.

I've heard all kinds of people suggest that you can tack a wire to
the fence in your backyard and run a wire to your radio and get
decent reception or maybe just better reception. "Better reception
than what?", you ask? Good point. I guess I don't recall what the
alternative was for sure, but I think it was one of us neophytes
trying to get away from the whip again. And I haven't heard it just
once; I've heard it many times. Did they not actually mean tack it
to the fence? Did they really mean use stand-offs and attach it to
the fence. I don't think so, because most asking the question were
trying to find a way to hide the antenna from the neighbors or the
homeowners association.

I've heard others say they live out in the boonies and have laid
1000 feet of long wire on the ground and obtained terrific
reception. (I suppose a thousand feet of any kind of wire is bound
to receive something!) This seems very much like laying a wire on
the roof of one's house with one major difference: out there in the
boonies you would have less interference from the junk most of us
have in our homes and those next door to us.

Finally, I assume Laura was talking about laying insulated wire on
her roof to improve reception. I'm not sure that bare wire would be
a no-no (heck, I'm new to this stuff, too), but I've heard the type
of wire doesn't really make that much difference (within reason). I
suspect this large roll of #14 solid, insulated wire used to wire
homes will work just as well as most and better than some.

Then we have that connection thing. The guys who have been into
this hobby for a while assume we all know how and where to connect
the downlead to the main antenna wire. My head spins with all of
the detail, but its kind of fun searching for answers ....
especially when you have a bunch of people who you can drag them
out of.

All I'm sure of is that the Wellbrook is in my future.

Harlan

"Joe Analssandrini" wrote in message
oups.com...
Hello Laura,

The idea of walking around your area (and the roof) with your
radio in hand to see if interference is greater or lesser at
various locations is sound. See if you can find a place which is
relatively noise-free. I'm afraid a length of wire just lain on
the roof will probably be unsatisfactory; it should be raised
much higher and must not touch anything. It should be attached to
ceramic (or similar) insulators and those insulators affixed to
supports, with suitable strain-relief. You can use coaxial cable
(RG-6 or RG-8) as a lead-in, or you can even try a twin-lead (300
Ohm) wire and terminate that in a 3.5 mm plug. If you do use
coax, I have found that Radio Shack does indeed sell adapters for
attaching it to your radio. I have used a BNC connector at the
end of coax, then a BNC to RCA adapter, and finally an RCA to 3.5
mm plug adapter to connect an outdoor antenna to a portable radio
(I did this years ago when I was able to have an outdoor antenna;
it worked just fine.) I have done something similar to allow my
Wellbrook antenna to be used with my Sony ICF-SW7600GR.

If, however, you find that in your location there is nowhere
without electrical noise, you've got problems.

Are those restaurant ventilators ever turned off, perhaps in the
middle of the night? If you try your radio then and find no
interference, you've found its source.

If those machines are indeed the cause of your interference, the
only type of antenna which can overcome that (to a greater or
lesser extent) is a balanced loop design, such as the Wellbrook,
and, as you know, they are expensive (but well-worth the money if
you can afford them). What you'll spend or do depends just how
serious you are about short wave listening.

If you find that placing your radio (using its whip) near a
window on the side of your house farthest away from the
ventilators results in lower noise levels, you might try an AOR
WL500 Window Loop Antenna which can be mounted in that window. It
is a loop of unbalanced design, according to PASSPORT, but may
help reduce some local electrical noise. In my case, I tried it
before I bought the Wellbrook ALA 330S and found it to be a great
help in my location, better than any other antenna I had
previously tried (I still use it with my Satellit 800), and it is
a great match for a portable radio (the Sony AN-LP1 is also a
good antenna for portables, but, in my experience, does not
reduce local electrical noise at all). It terminates in a BNC so
the Radio Shack adapters I mentioned above will easily adapt that
antenna to your radio. It may be worth a try though it, too, is
expensive and, frankly, is no match for the Wellbrook. If the
WL500 works fairly well, then the Wellbrook will work very well.

I hope that is of some help to you. Some of the other posts here
also have good ideas. Antennas are "scientifically" designed. But
"science" is no good at all when it comes to determining what
will work at a specific location. Only trial and error will tell
you that.

All the best,

Joe

laura fairhead wrote:
Hi,

Can Joe or anyone else explain to me a few things; I am trying
to set up a antenna on the roof as reception is really bad using
the indoor whip (lots of interference I live next door to a
restaurant ventilator farm and I think that may be a problem).
Anyway I am thinking of getting a length of wire and just laying
it on top of the roof under a couple of bricks to stop it
getting blown around. The thing I don't get is the connection
down the side of the house - I need to use a different cable
yes?

I have heard people specify a length of "radio coax" is suitable
but I do not understand how this could be any use without the
shielding being grounded - could someone explain?

My roberts R861 has a minijack anntena input - which has 2
connections on the plug - are they both used or is only one? If
I use a thick cable to run into the house would I need any
special attention to connect that to the minijack?

What sort of length wire should I use on the roof, is it just a
case of the longer the better?

Thanks in advance for any advice

bestwishes laura


I have never owned a Sangean ATS 909 nor do I know anyone who
does. According to PASSPORT TO WORLD BAND RADIO, the
Sangean/Roberts works BEST off its AC adapter as it "eats"
batteries. An external antenna is necessary also, as it lacks
sensitivity with its whip (according to them).

A long wire, or loop antenna, mounted on your roof would be
ideal. Try buying a length of insulated wire, two ceramic or
equivalent stand-off insulators (to isolate the antenna from
whatever support you use) and some lead-in wire; attach the
appropriate plug to the lead-in to attach to the radio and
you're in business. No separate ground is necessary, but make
sure you DISCONNECT the antenna whenever the radio is not in
use and, especially, during local thunderstorms. (NEVER use
ANY electronic appliance during a thunderstorm; storms only
last a half-hour or so.)

Do NOT let your antenna proper or the lead-in touch anything
metallic; that will degrade the signal.

--
echo |sed 's/\(.\)\(.\)/\2\1/g'


--
Telamon
Ventura, California

I'm glad to hear you are operating safely.

In article ,
"CW" wrote:

"Telamon" wrote in message
..
.
It looks like everyone on this thread has top posted so I will just so
it continues to make sense.

It's good to see that you have finally decided to do it right.

There is no problem laying the wire on the roof as long as it not near
any significantly long conductors. The impedance of the wire will be a
little lower than if it was hanging in mid air. The impedance of the
wire will drop much lower if it and the roof are wet, which will not
present a problem for receiving.

I would not use this as a transmitting antenna. It is a worse situation
when the roof is wet but even dry you are heating your roof with the RF
energy and this could start a fire if enough power is used.

The wire's measured impedance at the opperating frequency was about 100
ohms. 10 watts at 100 ohms gives less than half an amp. I wouldn't be to
concerned on an asphalt roof.

In article ,
"CW" wrote:

You are quite right to question this. I have an antenna wire laying
directly on my roof. It's been there for over ten years and works as
well as the one I have in the back yard that's totally suspended. The
one on the roof is bare wire. I have used it for transmitting where
it also works fine, as long as it's not raining. In wet whether, the
SWR goes nuts but this would not be of any concern for receiving. You
are right about the house electrical wire. Thousands of ham antennas
have been made from it.

"H Davis" wrote in message
...
First, my thanks to Laura for asking a question that guys probably
wouldn't ask anymore than we would ask directions if lost. In both
cases we seem to be satisfied with wandering around.

Also, once again thanks to Joe for a somewhat complete answer to
Laura's question. (I'd love to get Joe over here for a long
conversation and just pick his brain for a few hours.) But I would
like an even more complete answer. Joe and others seem to feel that
you can't just lay a wire on your roof and hold it down somehow and
still get better reception that you get with the whip indoors. I'm
thinking you aren't satisfied with that answer. If you are, I
apologize. I'm not satisfied.

I've heard all kinds of people suggest that you can tack a wire to
the fence in your backyard and run a wire to your radio and get
decent reception or maybe just better reception. "Better reception
than what?", you ask? Good point. I guess I don't recall what the
alternative was for sure, but I think it was one of us neophytes
trying to get away from the whip again. And I haven't heard it just
once; I've heard it many times. Did they not actually mean tack it
to the fence? Did they really mean use stand-offs and attach it to
the fence. I don't think so, because most asking the question were
trying to find a way to hide the antenna from the neighbors or the
homeowners association.

I've heard others say they live out in the boonies and have laid
1000 feet of long wire on the ground and obtained terrific
reception. (I suppose a thousand feet of any kind of wire is bound
to receive something!) This seems very much like laying a wire on
the roof of one's house with one major difference: out there in the
boonies you would have less interference from the junk most of us
have in our homes and those next door to us.

Finally, I assume Laura was talking about laying insulated wire on
her roof to improve reception. I'm not sure that bare wire would be
a no-no (heck, I'm new to this stuff, too), but I've heard the type
of wire doesn't really make that much difference (within reason). I
suspect this large roll of #14 solid, insulated wire used to wire
homes will work just as well as most and better than some.

Then we have that connection thing. The guys who have been into
this hobby for a while assume we all know how and where to connect
the downlead to the main antenna wire. My head spins with all of
the detail, but its kind of fun searching for answers ....
especially when you have a bunch of people who you can drag them
out of.

All I'm sure of is that the Wellbrook is in my future.

Harlan

"Joe Analssandrini" wrote in message
oups.com...
Hello Laura,

The idea of walking around your area (and the roof) with your
radio in hand to see if interference is greater or lesser at
various locations is sound. See if you can find a place which is
relatively noise-free. I'm afraid a length of wire just lain on
the roof will probably be unsatisfactory; it should be raised
much higher and must not touch anything. It should be attached to
ceramic (or similar) insulators and those insulators affixed to
supports, with suitable strain-relief. You can use coaxial cable
(RG-6 or RG-8) as a lead-in, or you can even try a twin-lead (300
Ohm) wire and terminate that in a 3.5 mm plug. If you do use
coax, I have found that Radio Shack does indeed sell adapters for
attaching it to your radio. I have used a BNC connector at the
end of coax, then a BNC to RCA adapter, and finally an RCA to 3.5
mm plug adapter to connect an outdoor antenna to a portable radio
(I did this years ago when I was able to have an outdoor antenna;
it worked just fine.) I have done something similar to allow my
Wellbrook antenna to be used with my Sony ICF-SW7600GR.

If, however, you find that in your location there is nowhere
without electrical noise, you've got problems.

Are those restaurant ventilators ever turned off, perhaps in the
middle of the night? If you try your radio then and find no
interference, you've found its source.

If those machines are indeed the cause of your interference, the
only type of antenna which can overcome that (to a greater or
lesser extent) is a balanced loop design, such as the Wellbrook,
and, as you know, they are expensive (but well-worth the money if
you can afford them). What you'll spend or do depends just how
serious you are about short wave listening.

If you find that placing your radio (using its whip) near a
window on the side of your house farthest away from the
ventilators results in lower noise levels, you might try an AOR
WL500 Window Loop Antenna which can be mounted in that window. It
is a loop of unbalanced design, according to PASSPORT, but may
help reduce some local electrical noise. In my case, I tried it
before I bought the Wellbrook ALA 330S and found it to be a great
help in my location, better than any other antenna I had
previously tried (I still use it with my Satellit 800), and it is
a great match for a portable radio (the Sony AN-LP1 is also a
good antenna for portables, but, in my experience, does not
reduce local electrical noise at all). It terminates in a BNC so
the Radio Shack adapters I mentioned above will easily adapt that
antenna to your radio. It may be worth a try though it, too, is
expensive and, frankly, is no match for the Wellbrook. If the
WL500 works fairly well, then the Wellbrook will work very well.

I hope that is of some help to you. Some of the other posts here
also have good ideas. Antennas are "scientifically" designed. But
"science" is no good at all when it comes to determining what
will work at a specific location. Only trial and error will tell
you that.

All the best,

Joe

laura fairhead wrote:
Hi,

Can Joe or anyone else explain to me a few things; I am trying
to set up a antenna on the roof as reception is really bad using
the indoor whip (lots of interference I live next door to a
restaurant ventilator farm and I think that may be a problem).
Anyway I am thinking of getting a length of wire and just laying
it on top of the roof under a couple of bricks to stop it
getting blown around. The thing I don't get is the connection
down the side of the house - I need to use a different cable
yes?

I have heard people specify a length of "radio coax" is suitable
but I do not understand how this could be any use without the
shielding being grounded - could someone explain?

My roberts R861 has a minijack anntena input - which has 2
connections on the plug - are they both used or is only one? If
I use a thick cable to run into the house would I need any
special attention to connect that to the minijack?

What sort of length wire should I use on the roof, is it just a
case of the longer the better?

Thanks in advance for any advice

bestwishes laura


I have never owned a Sangean ATS 909 nor do I know anyone who
does. According to PASSPORT TO WORLD BAND RADIO, the
Sangean/Roberts works BEST off its AC adapter as it "eats"
batteries. An external antenna is necessary also, as it lacks
sensitivity with its whip (according to them).

A long wire, or loop antenna, mounted on your roof would be
ideal. Try buying a length of insulated wire, two ceramic or
equivalent stand-off insulators (to isolate the antenna from
whatever support you use) and some lead-in wire; attach the
appropriate plug to the lead-in to attach to the radio and
you're in business. No separate ground is necessary, but make
sure you DISCONNECT the antenna whenever the radio is not in
use and, especially, during local thunderstorms. (NEVER use
ANY electronic appliance during a thunderstorm; storms only
last a half-hour or so.)

Do NOT let your antenna proper or the lead-in touch anything
metallic; that will degrade the signal.

--
echo |sed 's/\(.\)\(.\)/\2\1/g'


--
Telamon
Ventura, California

--
Telamon
Ventura, California

You have a point about the fire hazard. At 10 watts, there was little to no
risk. I wouldn't turn the power up though.

"Telamon" wrote in message
...
I'm glad to hear you are operating safely.

Hiya,

Thanx everyone for your advice. We got up on the roof finally
today and so now I know what we are dealing with. A friend
gave me some 15 metres of 75 ohm coax cable which I'm going
to use for the lead in and I have a good 5 metres or more of
bellwire I found hanging around which I'm going to connect to
it and use as the aerial. It is standard bellwire so it has
two wires and I'm thinking to join them together (that won't
cause any problems?) anyway rather than laying it on the ground
I think I'm going to tie the wire around a chimney stack at one
end and around a satellite dish mount at the other so it will be
off the ground and sloping (about 1/2 metre at one end and 1.5 at
the other). I've heard a lot about using some sort of pulley system
here and not just using the wire direct at each end but I don't
really know how I can make that easily. I do have some string
could I just use that at each end or does it have to be more
elaborate? Anyway we are probably going up to the roof a few times
now, I am also trying to sort out the satellite dish at the same
time. I had a great time the other evening listening to local radio
hams having a bit of a shin-dig on the 80metre band - I think I am
definently going to get a book about aerials, how they work and
how to make them etc it's obviously very very important. Well, so,
once again thanx for all your help, gradually I'm learning much
more about this fascinating subject. Sorry not to post sooner but
I haven't been on-line for a while and my keyboard went so the computer
has been out of action and of course I have been spending an interminable
amount of time messing around with things and reading etc, thanx Joe
particularly for a very informative post, your idea about moving around
and detecting and identifying electrical noise was most enlightening;
it's ironic that I'm working on setting up a satellite dish too and
the satellite box was emitting a huge amount of electrical interference!
Anyway hopefully next time I post I will have news of a much improved
signal (sometimes I scan from 4000 to 8000 and get 3 stations but at night
it is burgeoning with stations) and even have attainned one of the main
objects which is to receive Voice of Korea,.. seeya

bestwishesfrom
laura




On 27 Jan 2005 16:16:59 -0800, "RHF" wrote:

LF,
.
An "On-the-Roof" Shortwave Antenna may be a good idea;
and an "In-the-Attic" Shortwave Antenna can also work well.
.
But when you have RFI / EMF Man Made Noise Problems
usually one sure way of reducing them is to use a Loop
Antenna to Null-Out the Noise Source or Peak the Signal
of the Radio Station you want to listen to.
.
An In-Door Loop Antenna is about as easy to build and
takes about the same amount of time money and effort
as an Out-Side {External} Shortwave Antenna.
.
READ - Four 'different' "In-Door" Loop Antennas Ideas
http://groups.yahoo.com/group/Shortw...a/message/1933
.
Specifically take-a-look-at the : In-Door "On-the-Wall"
Loop Antenna for 'portable' AM/FM Shortwave Radios that
use a 1/8" (3.5mm) Jack for the External Antenna like your
Roberts R861 Radio.
http://groups.yahoo.com/group/Shortw...a/message/1845
.
This Antenna can be Mounted with Two Cup-Hooks
and a 8oz Fish Weight to position the Bottom-Center.
.
Try it on one wall and then the adjacent side wall (90*)
.
iane ~ RHF
.
All are WELCOME and "Invited to Join" the
Shortwave Listener (SWL) Antenna eGroup on YAHOO !
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
.
Some Say: On A Clear Day You Can See Forever.
http://groups.yahoo.com/group/Shortw...na/message/502
.
I BELIEVE: On A Clear Night . . .
You Can Hear Forever and Beyond, The BEYOND !
With a Shortwave Listener SWL Antenna of your own making.
"If You Build It {SWL Antenna} You Will Hear Them !"
.
.


--
echo |sed 's/\(.\)\(.\)/\2\1/g'

laura fairhead wrote:
Hiya,

Thanx everyone for your advice. We got up on the roof finally
today and so now I know what we are dealing with. A friend
gave me some 15 metres of 75 ohm coax cable which I'm going
to use for the lead in and I have a good 5 metres or more of
bellwire I found hanging around which I'm going to connect to
it and use as the aerial. It is standard bellwire so it has
two wires and I'm thinking to join them together (that won't
cause any problems?) anyway rather than laying it on the ground
I think I'm going to tie the wire around a chimney stack at one
end and around a satellite dish mount at the other so it will be
off the ground and sloping (about 1/2 metre at one end and 1.5 at
the other). I've heard a lot about using some sort of pulley system
here and not just using the wire direct at each end but I don't
really know how I can make that easily. I do have some string
could I just use that at each end or does it have to be more
elaborate? Anyway we are probably going up to the roof a few times
now, I am also trying to sort out the satellite dish at the same
time. I had a great time the other evening listening to local radio
hams having a bit of a shin-dig on the 80metre band - I think I am
definently going to get a book about aerials, how they work and
how to make them etc it's obviously very very important. Well, so,
once again thanx for all your help, gradually I'm learning much
more about this fascinating subject. Sorry not to post sooner but
I haven't been on-line for a while and my keyboard went so the
computer
has been out of action and of course I have been spending an
interminable
amount of time messing around with things and reading etc, thanx Joe
particularly for a very informative post, your idea about moving
around
and detecting and identifying electrical noise was most enlightening;
it's ironic that I'm working on setting up a satellite dish too and
the satellite box was emitting a huge amount of electrical
interference!
Anyway hopefully next time I post I will have news of a much improved
signal (sometimes I scan from 4000 to 8000 and get 3 stations but at
night
it is burgeoning with stations) and even have attainned one of the
main
objects which is to receive Voice of Korea,.. seeya

bestwishesfrom
laura




On 27 Jan 2005 16:16:59 -0800, "RHF"
wrote:

LF,
.
An "On-the-Roof" Shortwave Antenna may be a good idea;
and an "In-the-Attic" Shortwave Antenna can also work well.
.
But when you have RFI / EMF Man Made Noise Problems
usually one sure way of reducing them is to use a Loop
Antenna to Null-Out the Noise Source or Peak the Signal
of the Radio Station you want to listen to.
.
An In-Door Loop Antenna is about as easy to build and
takes about the same amount of time money and effort
as an Out-Side {External} Shortwave Antenna.
.
READ - Four 'different' "In-Door" Loop Antennas Ideas
http://groups.yahoo.com/group/Shortw...a/message/1933
.
Specifically take-a-look-at the : In-Door "On-the-Wall"
Loop Antenna for 'portable' AM/FM Shortwave Radios that
use a 1/8" (3.5mm) Jack for the External Antenna like your
Roberts R861 Radio.
http://groups.yahoo.com/group/Shortw...a/message/1845
.
This Antenna can be Mounted with Two Cup-Hooks
and a 8oz Fish Weight to position the Bottom-Center.
.
Try it on one wall and then the adjacent side wall (90*)
.
iane ~ RHF
.
All are WELCOME and "Invited to Join" the
Shortwave Listener (SWL) Antenna eGroup on YAHOO !
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
.
Some Say: On A Clear Day You Can See Forever.
http://groups.yahoo.com/group/Shortw...na/message/502
.
I BELIEVE: On A Clear Night . . .
You Can Hear Forever and Beyond, The BEYOND !
With a Shortwave Listener SWL Antenna of your own making.
"If You Build It {SWL Antenna} You Will Hear Them !"
.
.


--
echo |sed 's/\(.\)\(.\)/\2\1/g'

You really want to use either string, or someother insulator to tie
the antenna wire to each support.
Using two conductor wire, with bith wires connected in common will not
hurt anything.
If you can seprate the paired wires into and have 10M of wire instead
of 5, the reuslts will be much better. As a general rule, the longer
the wire, the better the reception. Most of us don't have enough space
to worry about going too long.
Terry