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Old December 2nd 04, 06:23 PM
Dave
 
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Default ? for the group

I recently installed a makeshift antenna on my roof similar to the
"temporary" one I have been using for a couple of years, but its performance
is severely degraded (not quite as good as my whip antenna, by itself). Now
I think I have found the problem, but want to check with those on the group
to confirm my suspicions. I used RG59 coax in combination with 300-ohm/50
ohm baluns, but now find a source of information that says RG59 is 75-ohm,
not 52 ohm like the guy at the parts depot told me. Which do I believe?
The (young) guy who cut the cable for me, or the book on RF design that some
people says is full of mistakes? What is the actual impedance of RG59 coax?

Thanks for any help...

Dave



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Old December 2nd 04, 06:45 PM
Dave
 
Posts: n/a
Default


"Michael Lawson" wrote in message
news

"Dave" wrote in message
...
I recently installed a makeshift antenna on my roof similar to the
"temporary" one I have been using for a couple of years, but its

performance
is severely degraded (not quite as good as my whip antenna, by

itself). Now
I think I have found the problem, but want to check with those on

the group
to confirm my suspicions. I used RG59 coax in combination with

300-ohm/50
ohm baluns, but now find a source of information that says RG59 is

75-ohm,
not 52 ohm like the guy at the parts depot told me. Which do I

believe?
The (young) guy who cut the cable for me, or the book on RF design

that some
people says is full of mistakes? What is the actual impedance of

RG59 coax?

RG-59/RG-6 is 75 ohm, and RG-58/RG-8x/RG-8 is 52 ohm.
How long of a run do you have from the antenna to the
receiver??

I'd suspect something more than just the coax if you've
got severely degraded performance. What's the radio
and the type of antenna you're using??

--Mike L.




Thanks for the quick response, Mike!

65 feet of coax between the radio (DX-402/ATS-505) and the antenna (200 feet
of 300 ohm twin-lead hidden along the ridge on the roof of the house.) And
I don't think I would call it "severely" degraded, only slightly so. Only a
little less than the old "temporary" antenna (60 feet of four strand copper
wire thrown over the house.) Also, the new antenna is oriented primarily E/W
while the "temporary" antenna was oriented primarily N/S, if that matters.

Thanks again for the help.

Dave



  #3   Report Post  
Old December 2nd 04, 06:48 PM
dxAce
 
Posts: n/a
Default



Dave wrote:

I recently installed a makeshift antenna on my roof similar to the
"temporary" one I have been using for a couple of years, but its performance
is severely degraded (not quite as good as my whip antenna, by itself). Now
I think I have found the problem, but want to check with those on the group
to confirm my suspicions. I used RG59 coax in combination with 300-ohm/50
ohm baluns, but now find a source of information that says RG59 is 75-ohm,
not 52 ohm like the guy at the parts depot told me. Which do I believe?
The (young) guy who cut the cable for me, or the book on RF design that some
people says is full of mistakes? What is the actual impedance of RG59 coax?


75 ohms.

dxAce
Michigan
USA


  #4   Report Post  
Old December 2nd 04, 06:49 PM
Michael Lawson
 
Posts: n/a
Default


"Dave" wrote in message
...
I recently installed a makeshift antenna on my roof similar to the
"temporary" one I have been using for a couple of years, but its

performance
is severely degraded (not quite as good as my whip antenna, by

itself). Now
I think I have found the problem, but want to check with those on

the group
to confirm my suspicions. I used RG59 coax in combination with

300-ohm/50
ohm baluns, but now find a source of information that says RG59 is

75-ohm,
not 52 ohm like the guy at the parts depot told me. Which do I

believe?
The (young) guy who cut the cable for me, or the book on RF design

that some
people says is full of mistakes? What is the actual impedance of

RG59 coax?

RG-59/RG-6 is 75 ohm, and RG-58/RG-8x/RG-8 is 52 ohm.
How long of a run do you have from the antenna to the
receiver??

I'd suspect something more than just the coax if you've
got severely degraded performance. What's the radio
and the type of antenna you're using??

--Mike L.



  #5   Report Post  
Old December 2nd 04, 06:56 PM
Dave
 
Posts: n/a
Default


"dxAce" wrote in message
...


Dave wrote:

I recently installed a makeshift antenna on my roof similar to the
"temporary" one I have been using for a couple of years, but its

performance
is severely degraded (not quite as good as my whip antenna, by itself).

Now
I think I have found the problem, but want to check with those on the

group
to confirm my suspicions. I used RG59 coax in combination with

300-ohm/50
ohm baluns, but now find a source of information that says RG59 is

75-ohm,
not 52 ohm like the guy at the parts depot told me. Which do I believe?
The (young) guy who cut the cable for me, or the book on RF design that

some
people says is full of mistakes? What is the actual impedance of RG59

coax?

75 ohms.

dxAce
Michigan
USA



Thanks. Noted.

Dave





  #6   Report Post  
Old December 2nd 04, 07:10 PM
Michael Lawson
 
Posts: n/a
Default


"Dave" wrote in message
...

"Michael Lawson" wrote in message
news

"Dave" wrote in message
...
I recently installed a makeshift antenna on my roof similar to

the
"temporary" one I have been using for a couple of years, but its

performance
is severely degraded (not quite as good as my whip antenna, by

itself). Now
I think I have found the problem, but want to check with those

on
the group
to confirm my suspicions. I used RG59 coax in combination with

300-ohm/50
ohm baluns, but now find a source of information that says RG59

is
75-ohm,
not 52 ohm like the guy at the parts depot told me. Which do I

believe?
The (young) guy who cut the cable for me, or the book on RF

design
that some
people says is full of mistakes? What is the actual impedance

of
RG59 coax?

RG-59/RG-6 is 75 ohm, and RG-58/RG-8x/RG-8 is 52 ohm.
How long of a run do you have from the antenna to the
receiver??

I'd suspect something more than just the coax if you've
got severely degraded performance. What's the radio
and the type of antenna you're using??

--Mike L.




Thanks for the quick response, Mike!

65 feet of coax between the radio (DX-402/ATS-505) and the antenna

(200 feet
of 300 ohm twin-lead hidden along the ridge on the roof of the

house.) And
I don't think I would call it "severely" degraded, only slightly so.

Only a
little less than the old "temporary" antenna (60 feet of four strand

copper
wire thrown over the house.) Also, the new antenna is oriented

primarily E/W
while the "temporary" antenna was oriented primarily N/S, if that

matters.

The orientation does matter if you're not using a vertical,
but the first thing that popped into my mind was overloading
the ATS-505 with 200 feet of antenna wire. The longest
I've ever run into my old DX-440/ATS-803A was about
40-50 feet, and while I never overloaded it, I've never
tried anything close to 200 feet into it.

But yeah, the E/W orientation will work well for stations
that are north or south of you (like tropical band stuff),
but not so good for hearing things east or west of you
(like from Europe or Africa or -depending on where
you're at- relays like Sackville).

If you can get into the attic, try running some of the same
antenna wire north/south and see if you get the same
response.

--Mike L.



  #7   Report Post  
Old December 2nd 04, 07:32 PM
Dale Parfitt
 
Posts: n/a
Default


"



Thanks for the quick response, Mike!

65 feet of coax between the radio (DX-402/ATS-505) and the antenna

(200 feet
of 300 ohm twin-lead hidden along the ridge on the roof of the

house.) And
I don't think I would call it "severely" degraded, only slightly so.

Only a
little less than the old "temporary" antenna (60 feet of four strand

copper
wire thrown over the house.) Also, the new antenna is oriented

primarily E/W
while the "temporary" antenna was oriented primarily N/S, if that

matters.

The orientation does matter if you're not using a vertical,
but the first thing that popped into my mind was overloading
the ATS-505 with 200 feet of antenna wire. The longest
I've ever run into my old DX-440/ATS-803A was about
40-50 feet, and while I never overloaded it, I've never
tried anything close to 200 feet into it.


But yeah, the E/W orientation will work well for stations
that are north or south of you (like tropical band stuff),
but not so good for hearing things east or west of you
(like from Europe or Africa or -depending on where
you're at- relays like Sackville).


Unless the antenna is a approx. 1/2 wavelength up or higher ( at tropical
band= 150' or so) the end nulls fill in making even horizontal antennas near
omni.

Guess my question is, how are you connecting the twin lead- if simply
connecting it to the balun, you have little more than a 300 Ohm transmission
line, not an antenna.
In fact, if the baluns were perfectly balanced, and the twin lead clear of
metallic objects ( which would unbalance it) you would theoretically get
zero signal.
Dale W4OP


  #8   Report Post  
Old December 2nd 04, 07:37 PM
Dave
 
Posts: n/a
Default


"Dale Parfitt" wrote in message
news:25Krd.8148$1z5.1438@trnddc06...

"



Thanks for the quick response, Mike!

65 feet of coax between the radio (DX-402/ATS-505) and the antenna

(200 feet
of 300 ohm twin-lead hidden along the ridge on the roof of the

house.) And
I don't think I would call it "severely" degraded, only slightly so.

Only a
little less than the old "temporary" antenna (60 feet of four strand

copper
wire thrown over the house.) Also, the new antenna is oriented

primarily E/W
while the "temporary" antenna was oriented primarily N/S, if that

matters.

The orientation does matter if you're not using a vertical,
but the first thing that popped into my mind was overloading
the ATS-505 with 200 feet of antenna wire. The longest
I've ever run into my old DX-440/ATS-803A was about
40-50 feet, and while I never overloaded it, I've never
tried anything close to 200 feet into it.


But yeah, the E/W orientation will work well for stations
that are north or south of you (like tropical band stuff),
but not so good for hearing things east or west of you
(like from Europe or Africa or -depending on where
you're at- relays like Sackville).


Unless the antenna is a approx. 1/2 wavelength up or higher ( at tropical
band= 150' or so) the end nulls fill in making even horizontal antennas

near
omni.

Guess my question is, how are you connecting the twin lead- if simply
connecting it to the balun, you have little more than a 300 Ohm

transmission
line, not an antenna.
In fact, if the baluns were perfectly balanced, and the twin lead clear of
metallic objects ( which would unbalance it) you would theoretically get
zero signal.
Dale W4OP



Hey Dale, thanks for jumping in.

Well, get the calculator out. The two freqs of interest to me are 9335 KHz
and 11710 KHz, so I am going to work with something between those two
numbers (10 MHz). If I am correct, 10 Mhz has a wavelength of 30 meters,
which works out to about 98 feet. And I am working with 200 feet. (Maybe I
should call this a long-wire antenna?) Question for you: what is an end
null?

And yes, I simply connected the 300-ohm to the baluns to the coax, to
another balun, and then a third that plugs into my external antenna socket.
And I a definetly getting a signal. Whatcha think?

Dave



  #9   Report Post  
Old December 2nd 04, 07:51 PM
dxAce
 
Posts: n/a
Default



Dave wrote:

"Dale Parfitt" wrote in message
news:25Krd.8148$1z5.1438@trnddc06...

"



Thanks for the quick response, Mike!

65 feet of coax between the radio (DX-402/ATS-505) and the antenna
(200 feet
of 300 ohm twin-lead hidden along the ridge on the roof of the
house.) And
I don't think I would call it "severely" degraded, only slightly so.
Only a
little less than the old "temporary" antenna (60 feet of four strand
copper
wire thrown over the house.) Also, the new antenna is oriented
primarily E/W
while the "temporary" antenna was oriented primarily N/S, if that
matters.

The orientation does matter if you're not using a vertical,
but the first thing that popped into my mind was overloading
the ATS-505 with 200 feet of antenna wire. The longest
I've ever run into my old DX-440/ATS-803A was about
40-50 feet, and while I never overloaded it, I've never
tried anything close to 200 feet into it.


But yeah, the E/W orientation will work well for stations
that are north or south of you (like tropical band stuff),
but not so good for hearing things east or west of you
(like from Europe or Africa or -depending on where
you're at- relays like Sackville).


Unless the antenna is a approx. 1/2 wavelength up or higher ( at tropical
band= 150' or so) the end nulls fill in making even horizontal antennas

near
omni.

Guess my question is, how are you connecting the twin lead- if simply
connecting it to the balun, you have little more than a 300 Ohm

transmission
line, not an antenna.
In fact, if the baluns were perfectly balanced, and the twin lead clear of
metallic objects ( which would unbalance it) you would theoretically get
zero signal.
Dale W4OP



Hey Dale, thanks for jumping in.

Well, get the calculator out. The two freqs of interest to me are 9335 KHz
and 11710 KHz, so I am going to work with something between those two
numbers (10 MHz). If I am correct, 10 Mhz has a wavelength of 30 meters,
which works out to about 98 feet. And I am working with 200 feet. (Maybe I
should call this a long-wire antenna?) Question for you: what is an end
null?

And yes, I simply connected the 300-ohm to the baluns to the coax, to
another balun, and then a third that plugs into my external antenna socket.
And I a definetly getting a signal. Whatcha think?


300 ohm to the baluns?, then to the coax, to another balun? then to a third
balun?

I'm going hmmmmmmmmmmmmmmmmmmmmmm.

dxAce
Michigan
USA


  #10   Report Post  
Old December 2nd 04, 07:59 PM
Dave
 
Posts: n/a
Default


"dxAce" wrote in message
...


Dave wrote:

"Dale Parfitt" wrote in message
news:25Krd.8148$1z5.1438@trnddc06...

"



Thanks for the quick response, Mike!

65 feet of coax between the radio (DX-402/ATS-505) and the antenna
(200 feet
of 300 ohm twin-lead hidden along the ridge on the roof of the
house.) And
I don't think I would call it "severely" degraded, only slightly

so.
Only a
little less than the old "temporary" antenna (60 feet of four

strand
copper
wire thrown over the house.) Also, the new antenna is oriented
primarily E/W
while the "temporary" antenna was oriented primarily N/S, if that
matters.

The orientation does matter if you're not using a vertical,
but the first thing that popped into my mind was overloading
the ATS-505 with 200 feet of antenna wire. The longest
I've ever run into my old DX-440/ATS-803A was about
40-50 feet, and while I never overloaded it, I've never
tried anything close to 200 feet into it.


But yeah, the E/W orientation will work well for stations
that are north or south of you (like tropical band stuff),
but not so good for hearing things east or west of you
(like from Europe or Africa or -depending on where
you're at- relays like Sackville).

Unless the antenna is a approx. 1/2 wavelength up or higher ( at

tropical
band= 150' or so) the end nulls fill in making even horizontal

antennas
near
omni.

Guess my question is, how are you connecting the twin lead- if simply
connecting it to the balun, you have little more than a 300 Ohm

transmission
line, not an antenna.
In fact, if the baluns were perfectly balanced, and the twin lead

clear of
metallic objects ( which would unbalance it) you would theoretically

get
zero signal.
Dale W4OP



Hey Dale, thanks for jumping in.

Well, get the calculator out. The two freqs of interest to me are 9335

KHz
and 11710 KHz, so I am going to work with something between those two
numbers (10 MHz). If I am correct, 10 Mhz has a wavelength of 30

meters,
which works out to about 98 feet. And I am working with 200 feet.

(Maybe I
should call this a long-wire antenna?) Question for you: what is an end
null?

And yes, I simply connected the 300-ohm to the baluns to the coax, to
another balun, and then a third that plugs into my external antenna

socket.
And I a definetly getting a signal. Whatcha think?


300 ohm to the baluns?, then to the coax, to another balun? then to a

third
balun?

I'm going hmmmmmmmmmmmmmmmmmmmmmm.

dxAce
Michigan
USA


And what are you thinking, while going hmmmmmmm... I don't have your
experience.

Thanks,

Dave


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