Adding any adaptor would seem to significantly move the radiating
portion of the antenna further away from the "ground plane" of the radio.
This should affect the operation of the antenna adversely. Comments?

Bob





In article ,
(Stephen G. Gulyas) wrote:

Do you have a need for a high-quality SMA-to-BNC rubber covered
factory look antenna adapter that is custom made to fit and protect
your H.T. or scanner radio?

Adapter allows you to:
Quickly change antennas to base, mobile or different style use.
Use the more popular and wider selection available of BNC antennas.
Prevent chassis connector wear or from coming loose due to antenna
changes.

Adapter features:
Gold plated contacts with a teflon insulator.
A low profile design with a rubber covering for a factory antenna
look.

In article
,
Bob Dixon wrote:

Adding any adaptor would seem to significantly move the radiating
portion of the antenna further away from the "ground plane" of the radio.
This should affect the operation of the antenna adversely. Comments?

Bob


Adding an adapter to a Transmission Line will have no effect, except to
add insertion loss of the adapter. Adding an adapter to the antenna
itself MAY cause the antenna charactoristics to change. Most SMA and BNC
connecters are used in Transmission Lines, and not antennas themselves.
The OP doesn't really explain where the adapter is to be used. Most
small handheld devices with external antenna connections have those
connection in the Transmission Line and not in the antenna itself.

Me

Me wrote:
In article
,
Bob Dixon wrote:


Adding any adaptor would seem to significantly move the radiating
portion of the antenna further away from the "ground plane" of the radio.
This should affect the operation of the antenna adversely. Comments?

Bob



Adding an adapter to a Transmission Line will have no effect, except to
add insertion loss of the adapter. Adding an adapter to the antenna
itself MAY cause the antenna charactoristics to change. Most SMA and BNC
connecters are used in Transmission Lines, and not antennas themselves.
The OP doesn't really explain where the adapter is to be used. Most
small handheld devices with external antenna connections have those
connection in the Transmission Line and not in the antenna itself.

Me

That is actually not quite true. On an HT, the transmission line ends
somewhere inside the radio. The SMA/BNC connector is part of the
antenna proper. If you add a sleeve (as the previous poster, "dixon",
says), you will be changing the antenna itself. ASCII schematic follows:

befo


|
| antenna
|
|
_ ground + bnc/sma
||
|| coax from PA strip
||
||

after

|
| antenna
|
|
||
|| shielded antenna (adapter)
||
_ ground (bnc
||
|| coax from PA strip
||
||

And as we remember, "maximum radiation at the current maximum" (that is,
the base of a classic 1/4 wave antenna), you are shielding the point of
maximum radiation.

From a practical standpoint, you will probably be using a gain-retarded
rubber duckie, and the 1 or 2 dB loss from even the worst adapter will
be swamped by the -10 dB gain of the duck (that is "minus 10 dB gain").
The rubber-duck will make a 5 watt transmitter sound like a 1/2 watt
one. Having another 1 dB of loss will make that 5-watt radio sound like
0.4 instead of 0.5. No big deal.

If you can keep your radio from being broken by using a quality adapter,
and with a negligible loss in performance, I say, "do it."

If you are talking about squeaking out every last bit of signal, such as
EME, the answer is "no". But if you are talking about walking around a
hamfest on 2m, then spend a few extra bucks to keep from fracturing your
antenna connector connection, which these days, most hams can't, or
don't know how to, fix. flames invited

Your mileage may vary.

Dave
KZ1O

In article ,
Dave Bushong wrote:

That is actually not quite true. On an HT, the transmission line ends
somewhere inside the radio. The SMA/BNC connector is part of the
antenna proper. If you add a sleeve (as the previous poster, "dixon",
says), you will be changing the antenna itself. ASCII schematic follows:

befo

I have been in the communications field for 35 years, and I have NEVER
seen a SMA/BNC antenna connector on a Handheld Radio that didn't
have a the RF Ground connected to the ground side of the connector.
there are some that use different antenna connectors than SMA/TNC?BNC
that are singleended but I have never seen one used that way.
CFR (Call for Rference) Tell us all which radios your talking about.
Make, Model, Version.


Me

Me wrote:
In article ,
Dave Bushong wrote:


That is actually not quite true. On an HT, the transmission line ends
somewhere inside the radio. The SMA/BNC connector is part of the
antenna proper. If you add a sleeve (as the previous poster, "dixon",
says), you will be changing the antenna itself. ASCII schematic follows:

befo


I have been in the communications field for 35 years, and I have NEVER
seen a SMA/BNC antenna connector on a Handheld Radio that didn't
have a the RF Ground connected to the ground side of the connector.
there are some that use different antenna connectors than SMA/TNC?BNC
that are singleended but I have never seen one used that way.
CFR (Call for Rference) Tell us all which radios your talking about.
Make, Model, Version.


Me

You missed my point, I think. The counterpoise is the (poor) metal of
the radio and of the user's hand. Any connector/adapter will be coaxial
and probably low loss, but the counterpoise stays put. The feedpoint
rises but the "ground" plane does not. For an SMA adapter, it might not
be enough to hear a difference, but the radiated signal will be worse
when using such an adapter.

73,
Dave

In article ,
Dave Bushong wrote:

You missed my point, I think. The counterpoise is the (poor) metal of
the radio and of the user's hand. Any connector/adapter will be coaxial
and probably low loss, but the counterpoise stays put. The feedpoint
rises but the "ground" plane does not. For an SMA adapter, it might not
be enough to hear a difference, but the radiated signal will be worse
when using such an adapter.

I'd say "may be worse" rather than "will be worse". In some cases, it
may be better.

From what I've seen (and measured) the actual impedances,
"counterpoise" effectiveness, etc. of HT antenna setups vary all over
the map, and change constantly depending on a whole bunch of
factors... how you grip the HT, whether you happen to be wearing a
glove, how you angle the HT near your head (antenna-loading effects
from the head can make SWR change dramatically), and probably whether
you're sweating or not.

A typical HT case is almost certainly _not_ serving as a tuned
counterpoise at 2 meters, nor is your arm and body.

Adding a centimeter or three of SMA-to-BNC connector to the length of
the "counterpoise" may have some small effect in some cases, but I
believe that [1] it's as likely to work for you as against you, and
[2] it's probably less than the sorts of impedance variations which a
typical HT has to face every day as it's moved around the user's head
during transmission.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Not to mention the fact that the reason you're adding the adapter is most
likely because you are putting a better antenna on the HT. I doubt what you
*might* lose by moving the feedpoint away from the "counterpoise" is not as
much as you gain by changing the antenna; otherwise, why bother? At higher
frequencies this may not be the case, but probably not within the realm of a
dual-band HT.

I've been using the Gulyas adapter for years now. I use it primarily for
attaching a Smiley 270 telescopic whip to my VX-5, since that antenna works
very well configured as a 5/8-wave on 70cm. The relative gain in
performance over the stock antenna is quite noticeable, so in that case, the
adapter causes no problems. The fit and appearance of the adapter on that
rig is great, too!

- Doug

"Dave Platt" wrote in message
...
In article ,
Dave Bushong wrote:

You missed my point, I think. The counterpoise is the (poor) metal of
the radio and of the user's hand. Any connector/adapter will be coaxial
and probably low loss, but the counterpoise stays put. The feedpoint
rises but the "ground" plane does not. For an SMA adapter, it might not
be enough to hear a difference, but the radiated signal will be worse
when using such an adapter.

I'd say "may be worse" rather than "will be worse". In some cases, it
may be better.

From what I've seen (and measured) the actual impedances,
"counterpoise" effectiveness, etc. of HT antenna setups vary all over
the map, and change constantly depending on a whole bunch of
factors... how you grip the HT, whether you happen to be wearing a
glove, how you angle the HT near your head (antenna-loading effects
from the head can make SWR change dramatically), and probably whether
you're sweating or not.

A typical HT case is almost certainly _not_ serving as a tuned
counterpoise at 2 meters, nor is your arm and body.

Adding a centimeter or three of SMA-to-BNC connector to the length of
the "counterpoise" may have some small effect in some cases, but I
believe that [1] it's as likely to work for you as against you, and
[2] it's probably less than the sorts of impedance variations which a
typical HT has to face every day as it's moved around the user's head
during transmission.

--
Dave Platt AE6EO

Dave Platt wrote:
In article ,
Dave Bushong wrote:


You missed my point, I think. The counterpoise is the (poor) metal of
the radio and of the user's hand. Any connector/adapter will be coaxial
and probably low loss, but the counterpoise stays put. The feedpoint
rises but the "ground" plane does not. For an SMA adapter, it might not
be enough to hear a difference, but the radiated signal will be worse
when using such an adapter.


I'd say "may be worse" rather than "will be worse". In some cases, it
may be better.
[...]

Tell me, specifically, in which cases that my info would not be true. I
made some measurements before I posted. Did you?

I was just saying that extending the feedpoint / current node, as was
suggested, will lower the radiated power. I measured field strength
measurements and then posted my results.

I still feel that the more aluminum in the sky, the better. Even if
there is some loss in adapters... mmmm.... bigger antennas, happier hams.

73,
Dave
kz1o

HT's are as close to having an isotropic antenna as anything to be had.

Dave WD9BDZ



Dave Platt wrote:

In article ,
Dave Bushong wrote:


You missed my point, I think. The counterpoise is the (poor) metal of
the radio and of the user's hand. Any connector/adapter will be coaxial
and probably low loss, but the counterpoise stays put. The feedpoint
rises but the "ground" plane does not. For an SMA adapter, it might not
be enough to hear a difference, but the radiated signal will be worse
when using such an adapter.


I'd say "may be worse" rather than "will be worse". In some cases, it
may be better.

From what I've seen (and measured) the actual impedances,
"counterpoise" effectiveness, etc. of HT antenna setups vary all over
the map, and change constantly depending on a whole bunch of
factors... how you grip the HT, whether you happen to be wearing a
glove, how you angle the HT near your head (antenna-loading effects
from the head can make SWR change dramatically), and probably whether
you're sweating or not.

A typical HT case is almost certainly _not_ serving as a tuned
counterpoise at 2 meters, nor is your arm and body.

Adding a centimeter or three of SMA-to-BNC connector to the length of
the "counterpoise" may have some small effect in some cases, but I
believe that [1] it's as likely to work for you as against you, and
[2] it's probably less than the sorts of impedance variations which a
typical HT has to face every day as it's moved around the user's head
during transmission.

In article ,
Dave Bushong wrote:

Me wrote:
In article ,
Dave Bushong wrote:


That is actually not quite true. On an HT, the transmission line ends
somewhere inside the radio. The SMA/BNC connector is part of the
antenna proper. If you add a sleeve (as the previous poster, "dixon",
says), you will be changing the antenna itself. ASCII schematic follows:

befo


I have been in the communications field for 35 years, and I have NEVER
seen a SMA/BNC antenna connector on a Handheld Radio that didn't
have a the RF Ground connected to the ground side of the connector.
there are some that use different antenna connectors than SMA/TNC?BNC
that are singleended but I have never seen one used that way.
CFR (Call for Rference) Tell us all which radios your talking about.
Make, Model, Version.


Me

You missed my point, I think. The counterpoise is the (poor) metal of
the radio and of the user's hand. Any connector/adapter will be coaxial
and probably low loss, but the counterpoise stays put. The feedpoint
rises but the "ground" plane does not. For an SMA adapter, it might not
be enough to hear a difference, but the radiated signal will be worse
when using such an adapter.

73,
Dave

No, you didn't read roy's post on how feedline and antennas systems
work......


Me