samw thing without rubber 3.75 at any electroncs store

what a rip off


but you know you can get in serious trouble without your rubbers . . .







Ed

samw thing without rubber 3.75 at any electroncs store

what a rip off


but you know you can get in serious trouble without your rubbers . . .







Ed

Brian wrote in
:

samw thing without rubber 3.75 at any electroncs store

what a rip off


And without the rubber, the flex and bending of the antenna gets directly
transferred to the sma connector. You'll be wishing you'd had some sort of
support before long, as the rig is in the shop with a broken sma connector.
Stephens connectors work well, I've had one for years, and think it was one
of the smarter accessories I've purchased. (Ft-50)


john

Brian wrote in
:

samw thing without rubber 3.75 at any electroncs store

what a rip off


And without the rubber, the flex and bending of the antenna gets directly
transferred to the sma connector. You'll be wishing you'd had some sort of
support before long, as the rig is in the shop with a broken sma connector.
Stephens connectors work well, I've had one for years, and think it was one
of the smarter accessories I've purchased. (Ft-50)


john

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

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