I'm relatively new to this--pardon any vernacular errors. I've a 50mW
veronica transmitter that I'm using around the house and yard. 9/12V DC
power source. It currently has two flexible wire leads serving as the
antenna and ground--each is 70cm in length and is directly soldered to
the PCB. I usually coil them up to keep the range at a minimum.

Is there anything I can do to change the existing antenna setup? I'd
like to be able to switch antennas to attain different coverages. I was
told the impedance on such a unit is different than that of common
connectors (BNC, F, etc). Is there any way to change this configuration
to accept a whip antenna or a rubber duck antenna? I tried wrapping the
existing wires around rabbit ears arranged vertically which seemed to
give me an option for increased range.

Thanks.

erichmadison wrote:

I'm relatively new to this--pardon any vernacular errors. I've a 50mW
veronica transmitter that I'm using around the house and yard. 9/12V DC
power source. It currently has two flexible wire leads serving as the
antenna and ground--each is 70cm in length and is directly soldered to
the PCB. I usually coil them up to keep the range at a minimum.

Is there anything I can do to change the existing antenna setup? I'd
like to be able to switch antennas to attain different coverages. I was
told the impedance on such a unit is different than that of common
connectors (BNC, F, etc). Is there any way to change this configuration
to accept a whip antenna or a rubber duck antenna? I tried wrapping the
existing wires around rabbit ears arranged vertically which seemed to
give me an option for increased range.

Thanks.


I'm guessing here.
It seems to me that if you have 140cm total antenna fed at the middle,
then you have a full size dipole (or close enough) at the FM-BC band.
That further suggests a 75 ohm output impedance.

It would take some work to match a rubber-duck antenna - and it wouldn't
be very efficient. However, you should be able to use a whip of about
70cm and not suffer too much for lack of the ground plane.

If increased range is the goal then 75-ohm cable to an outdoor antenna
(dipole, etc) would seem to be ideal. All would need to be done within
the regulations of your country, of course.

There's zillions of folks using the Veronica gear...keep asking around
and I'm sure you'll find something more definitive than my guesswork.

My 2c,

Bill

Bill,

One of the wires is a ground, the other is the antenna. Would this
still be a dipole? Thanks for your previous post!

Yes Bill.
It sounds like that is serving as a dipole.
I too would strongly suspect that is a 75 ohm BALANCED output.
You should be able to remove the wires which are serving as the "dipole" and
run them to a 1:1 balun and the other side of the balun to a 50-75 ohm
unbalanced antenna. Or, to the input of a FM power amp....

Warmest regards,
John

"erichmadison" wrote in message
oups.com...
| Bill,
|
| One of the wires is a ground, the other is the antenna. Would this
| still be a dipole? Thanks for your previous post!
|

erichmadison wrote:

Bill,

One of the wires is a ground, the other is the antenna. Would this
still be a dipole? Thanks for your previous post!

'Ground' has various implications when it comes to rf. If they tell you
to attach it to a water pipe or ground rod then it may be a true dc
ground. If they tell you to extend it just like the antenna side and
not connect it to anything, then its an RF ground plane...which can be
compared to rabbit ears, dipole, etc.

Is it balanced or not? Hard to guess.

-Bill

An "Unbalanced Dipole", interesting concept...

Regards,
John

"Bill" wrote in message
...
| erichmadison wrote:
|
| Bill,
|
| One of the wires is a ground, the other is the antenna. Would this
| still be a dipole? Thanks for your previous post!
|
| 'Ground' has various implications when it comes to rf. If they tell you
| to attach it to a water pipe or ground rod then it may be a true dc
| ground. If they tell you to extend it just like the antenna side and
| not connect it to anything, then its an RF ground plane...which can be
| compared to rabbit ears, dipole, etc.
|
| Is it balanced or not? Hard to guess.
|
| -Bill

What would happen if he didn't use a balun?

Roy Lewallen, W7EL

John Smith wrote:
Yes Bill.
It sounds like that is serving as a dipole.
I too would strongly suspect that is a 75 ohm BALANCED output.
You should be able to remove the wires which are serving as the "dipole" and
run them to a 1:1 balun and the other side of the balun to a 50-75 ohm
unbalanced antenna. Or, to the input of a FM power amp....

Warmest regards,
John

"erichmadison" wrote in message
oups.com...
| Bill,
|
| One of the wires is a ground, the other is the antenna. Would this
| still be a dipole? Thanks for your previous post!
|

What exactly do you mean by "balanced"?

If you put a balun between a "balanced" radio and a "balanced" antenna,
what would happen? What would happen if you put it between an
"unbalanced" radio and an "unbalanced" antenna? What would happen if you
connected an "unbalanced" radio to a "balanced" antenna without a balun?

Roy Lewallen, W7EL

John Smith wrote:
An "Unbalanced Dipole", interesting concept...

Regards,
John

"Bill" wrote in message
...
| erichmadison wrote:
|
| Bill,
|
| One of the wires is a ground, the other is the antenna. Would this
| still be a dipole? Thanks for your previous post!
|
| 'Ground' has various implications when it comes to rf. If they tell you
| to attach it to a water pipe or ground rod then it may be a true dc
| ground. If they tell you to extend it just like the antenna side and
| not connect it to anything, then its an RF ground plane...which can be
| compared to rabbit ears, dipole, etc.
|
| Is it balanced or not? Hard to guess.
|
| -Bill

John Smith wrote:

An "Unbalanced Dipole", interesting concept...

Regards,
John

Yeah, then its a quarter-wave vertical w/ground plane laying on its side :-)


-Bill

If the output is really Unbalanced, and he fed an unbalanced ant of 50
ohms--nothing--as likely a 1.5:1 (75/50) match as not...

Or, depending on the type of ant he picks (75 ohm bal/unbal), and taking for
granted the output of the rig is balanced--probably just a distortion of the
radiation field of the ant (won't EXACTLY perform as modeled)...

Even if he feeds a bal ant of 200 ohms (folded dipole, and output is
balanced, all he sees is a high (200/75) SWR, and distance is reduced...

But, hey, I am a newbie... that is only my best guess(s)...

Warmest regards,
John

"Roy Lewallen" wrote in message
...
| What would happen if he didn't use a balun?
|
| Roy Lewallen, W7EL
|
| John Smith wrote:
| Yes Bill.
| It sounds like that is serving as a dipole.
| I too would strongly suspect that is a 75 ohm BALANCED output.
| You should be able to remove the wires which are serving as the "dipole"
and
| run them to a 1:1 balun and the other side of the balun to a 50-75 ohm
| unbalanced antenna. Or, to the input of a FM power amp....
|
| Warmest regards,
| John
|
| "erichmadison" wrote in message
| oups.com...
| | Bill,
| |
| | One of the wires is a ground, the other is the antenna. Would this
| | still be a dipole? Thanks for your previous post!
| |
|
|