Replies interspersed.


"starman" wrote in message
...
Dave wrote:

I am using a DX-402 (aka Sangean ATS 505). I would be surprised if it
had a balanced antenna input, and have been thinking about just clipping
the external antenna to my whip after all. I hooked 20 feet of 300 ohm
twinlead to a 300/75 ohm transformer and miniplug last night and plugged
it in, but the signal strength was about half of what my whip gives me.
Therefore, the change in plans.

It would be a mistake to connect a good external antenna directly to the
whip. The receiver will almost certainly overload. You know the symptoms
for overloading now. If you build the low noise inverted-L, the coax can
be connected to the external antenna jack with a mini plug.


If it wasn't much worse than what I am dealing with right now, I can live
with it. Especially if I buy or build an antenna tuner, which I am planning
to add in one way or another. Let me ask you this, what makes the inverted
L so good for noise? I am taking what you say seriously, but if I install
the antenna on top of the roof and run it down the other side of the house
it will be quite close to our A/C compressor, which I expect to become a
significant source of EMI. What if I just ran it along the ridge of the
house and attached it to coax up *there*, before running the coax down the
side of the house and grounding the shield to the grounding rod? Seems like
that would eliminate a great deal of EMI from the A/C compressor, which I
cannot move.


I was planning on running the vertical portion of twinlead that went
from ground level/grounding rod/coax up to the eaves over the steel
siding, but I could just as easily run the coax up the side of the house,
which would put all of the twinlead above the steel siding. Still not "out
in the open" but probably the best I can do. Wifey doesn't want anything
that obviously says "Hi there, I'm an antenna!"

It's funny how women have an aversion to antennas. Must be an esthetic
thing. :-)

Wife read your comments and laughed. She says that if women designed
antennas they would be a lot prettier. Probably Modern Art, if I know her.




I am beginning to consider running the coax around to the end of the
house and up that side, and laying the twinlead along the ridge of the
roof from one end to the other. That would be a up a lot higher and a lot
more "out in the open."

The horizontal section (single wire) of an inverted-L could also run
along the roof ridge. The vertical downlead wire would connect to one
end of the horizontal section and run down the end wall of the house to
the ground. The balun would be located near the ground next to a ground
rod. The coax would go from the balun to the receiver. That's the design
of the low noise inverted-L except it's better to locate the antenna
away from the house when you can.

Away from the house is not possible. Even if it was, that would put it near
the power lines. How would I build a balun? (Websites/links?)

No problem with the questions. It's nice to see an interesting on
topic
thread for a change.

Thanks for the encouragement. I'm not yet sure what I will end up
doing,
but I want to make the best decision possible.

Gotta go. Wife has to get up at 5:00 and I am supposed to get up first and
fix breakfast. Long day tomorrow. I pulled up the grounding rod today
(using a car jack to lift it out) and then told my wife what I had done.
She asked what it was there for, and why didn't we still need it. Told her
the TV antenna used to be connected to it, but since we moved that it wasn't
being used. Now I need to install another grounding rod for the TV antenna
in it's new location. Wasn't thinking when I put it there and didn't ground
it. It's not hooked up anyway. We haven't even watched any broadcast
programs on that TV in years, using the small one with an independant
antenna in the bedroom instead. The big one is just used for watching
DVD's.

Thanks for the help.

Dave

The word balun to describe this device, while quite common, is incorrect. Go
he www.kc7nod.20m.com
Look for matching transformer.

"Dave" wrote in message
...
Away from the house is not possible. Even if it was, that would put it
near
the power lines. How would I build a balun? (Websites/links?)

It's an impedance matching transformer or unun. I use the word 'balun'
because most people haven't heard the term 'unun'.

CW wrote:

The word balun to describe this device, while quite common, is incorrect. Go
he www.kc7nod.20m.com
Look for matching transformer.

"Dave" wrote in message
...
Away from the house is not possible. Even if it was, that would put it
near
the power lines. How would I build a balun? (Websites/links?)


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We knew that you knew the difference. I was just insuring that Dave new
the difference.

"starman" wrote in message
...
It's an impedance matching transformer or unun. I use the word 'balun'
because most people haven't heard the term 'unun'.

CW wrote:

The word balun to describe this device, while quite common, is
incorrect. Go
he www.kc7nod.20m.com
Look for matching transformer.

"Dave" wrote in message
...
Away from the house is not possible. Even if it was, that would put
it
near
the power lines. How would I build a balun? (Websites/links?)


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I *think* I do. I'll definetly read more on the subject though.


Dave


"CW" wrote in message
...
We knew that you knew the difference. I was just insuring that Dave new
the difference.

"starman" wrote in message
...
It's an impedance matching transformer or unun. I use the word 'balun'
because most people haven't heard the term 'unun'.

CW wrote:

The word balun to describe this device, while quite common, is
incorrect. Go
he www.kc7nod.20m.com
Look for matching transformer.

"Dave" wrote in message
...
Away from the house is not possible. Even if it was, that would put
it
near
the power lines. How would I build a balun? (Websites/links?)


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So, a matching transformer is all I need? I have pretty much decided to use
300 ohm twinlead along the rood ridge with a 300/75 ohm matching transformer
to connect it to the coax, and more as needed between the coax and radio.
Will that honestly work?

Thanks,

Dave


"starman" wrote in message
...
It's an impedance matching transformer or unun. I use the word 'balun'
because most people haven't heard the term 'unun'.

CW wrote:

The word balun to describe this device, while quite common, is
incorrect. Go
he www.kc7nod.20m.com
Look for matching transformer.

"Dave" wrote in message
...
Away from the house is not possible. Even if it was, that would put
it
near
the power lines. How would I build a balun? (Websites/links?)


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Forgot to mention, I was going to connect the conductors on the far end so
as to have a longer single line. One side of the near end would be hanging
out in space, in other words, so as not to form a loop.

Dave


"Dave" wrote in message
...
So, a matching transformer is all I need? I have pretty much decided to
use
300 ohm twinlead along the rood ridge with a 300/75 ohm matching
transformer
to connect it to the coax, and more as needed between the coax and radio.
Will that honestly work?

Thanks,

Dave


"starman" wrote in message
...
It's an impedance matching transformer or unun. I use the word 'balun'
because most people haven't heard the term 'unun'.

CW wrote:

The word balun to describe this device, while quite common, is
incorrect. Go
he www.kc7nod.20m.com
Look for matching transformer.

"Dave" wrote in message
...
Away from the house is not possible. Even if it was, that would put
it
near
the power lines. How would I build a balun? (Websites/links?)


-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
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-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Dave wrote:

So, a matching transformer is all I need? I have pretty much decided to use
300 ohm twinlead along the rood ridge with a 300/75 ohm matching transformer
to connect it to the coax, and more as needed between the coax and radio.
Will that honestly work?

Thanks,

Dave

A 300/50 ohm transformer is the most common type for a shortwave folded
dipole. You can still use 75-ohm coax to the 50-ohm side of the
transformer. There would be a slight impedance mismatch but it's not
that important for a receiving antenna. I do not recommend using a
300/75 TV balun for this purpose because it's designed to operate at
much higher frequencies than shortwave. Remember that you *must* connect
the two wires in the ends of the twinlead together to make a folded
dipole. Otherwise the high impedance side of the matching transformer
(300-ohms) won't be the right value for the antenna. Finally, don't
expect this antenna to be great for all shortwave frequencies and
directions. We discussed why this is so in an earlier exchange.


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STARMAN,

Why Use a TV type 300 to 75 Ohm Matching Transformer with
your SWL Antenna and 'portable AM/FM/Shortwave Radio.

May I interject my opinion based on some simple observations
using both SWL/HAM Matching Transformers and the cheap TV
type 300 to 75 Ohm Matching Transformers.

ABOUT - The TV type 300 to 75 Ohm Matching Transformers a

* Easy to Find. {RadioShack, WalMart, Walgreens, Kragens, etc}

* Simple to Use. {How To - Hook-Em-Up is Self-Evident}

* Low Cost. {Under $5}

* Generally Functions well and Operates down to 5 MHz and
well above 30 MHz. (Most of the better quality ones are now
"Marked" for 5 MHz and up.)

* Provides Coverage of 'most' of the International
Shortwave Bands: 60M, 49M, 41M, 31M, 25M, 21M, 19M,
16M, 13M, and 11M. (But not 90M and 75M Bands)

* Plus 'helps' to "Attenuate" Strong AM/MW Signals
that create images in the Shortwave Bands.
{This is an Important Bonus.}

* Allows the 'direct' Connection "Hook-Up" of Low Cost
75 Ohm TV type Coax Cable as an antenna Lead-in-Line.

IMHO: For most/many 'portable' AM/FM/Shortwave Radios
using a TV type 300 to 75 Ohm Matching Transformer is
a very good alternative to a SWL/HAM Matching Transformer.
[ Value and Cost ]

iane ~ RHF
..
..
= = = starman wrote in message
= = = ...
Dave wrote:

So, a matching transformer is all I need? I have pretty much decided to use
300 ohm twinlead along the rood ridge with a 300/75 ohm matching transformer
to connect it to the coax, and more as needed between the coax and radio.
Will that honestly work?

Thanks,

Dave

A 300/50 ohm transformer is the most common type for a shortwave folded
dipole. You can still use 75-ohm coax to the 50-ohm side of the
transformer. There would be a slight impedance mismatch but it's not
that important for a receiving antenna. I do not recommend using a
300/75 TV balun for this purpose because it's designed to operate at
much higher frequencies than shortwave. Remember that you *must* connect
the two wires in the ends of the twinlead together to make a folded
dipole. Otherwise the high impedance side of the matching transformer
(300-ohms) won't be the right value for the antenna. Finally, don't
expect this antenna to be great for all shortwave frequencies and
directions. We discussed why this is so in an earlier exchange.


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Starman,

I am no longer intending to use a folded dipole, or a dipole of any kind. I
am currently planning to connect the conductors at the far end of the 300
ohm twinlead but only connect one side of the near end to the 300/75 ohm
matching transformer. Will this not work? I don't need perfection, just
reasonably good (I think.)

Thanks,

Dave


"starman" wrote in message
...
Dave wrote:

So, a matching transformer is all I need? I have pretty much decided to
use
300 ohm twinlead along the rood ridge with a 300/75 ohm matching
transformer
to connect it to the coax, and more as needed between the coax and
radio.
Will that honestly work?

Thanks,

Dave

A 300/50 ohm transformer is the most common type for a shortwave folded
dipole. You can still use 75-ohm coax to the 50-ohm side of the
transformer. There would be a slight impedance mismatch but it's not
that important for a receiving antenna. I do not recommend using a
300/75 TV balun for this purpose because it's designed to operate at
much higher frequencies than shortwave. Remember that you *must* connect
the two wires in the ends of the twinlead together to make a folded
dipole. Otherwise the high impedance side of the matching transformer
(300-ohms) won't be the right value for the antenna. Finally, don't
expect this antenna to be great for all shortwave frequencies and
directions. We discussed why this is so in an earlier exchange.


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