Hello and thanks for ahy help you can provide.

I have a small assisted hearing type transmitter that normally uses the
shield of the mic cable for the antenna. I need to change to a fixed
antenna for a particular application where there is no mic cable to
extend out.

The manufacturer says the antenna wire for this 651.85Mhz unit should be
48" long.

Can anyone tell me what that would equal in a rubber ducky antenna?

Thanks.

scooterspal wrote:
The manufacturer says the antenna wire for this 651.85Mhz unit should be
48" long.

Can anyone tell me what that would equal in a rubber ducky antenna?
===============================================
The transmitter operates on a wavelength of 300/651.85 equals 0.460 m or
460 mm.

48 inches equals 48*25.4 equals 1219mm So the 'recommended' antenna is
1219/460 equals 2.65 wavelength.

Does not make sense to me


Frank GM0CSZ / KN6WH

Highland Ham wrote:
scooterspal wrote:
The manufacturer says the antenna wire for this 651.85Mhz unit should
be 48" long.

Can anyone tell me what that would equal in a rubber ducky antenna?
===============================================
The transmitter operates on a wavelength of 300/651.85 equals 0.460 m or
460 mm.

48 inches equals 48*25.4 equals 1219mm So the 'recommended' antenna is
1219/460 equals 2.65 wavelength.

Does not make sense to me


Beverage?


- 73 de Mike N3LI -

(scooterspal) wrote in
:

Hello and thanks for ahy help you can provide.

I have a small assisted hearing type transmitter that normally uses
the shield of the mic cable for the antenna. I need to change to a
fixed antenna for a particular application where there is no mic
cable to extend out.

The manufacturer says the antenna wire for this 651.85Mhz unit
should be 48" long.

Can anyone tell me what that would equal in a rubber ducky antenna?

You appear to be posting from the US, so I thought I'd mention that if
this transmitter is an unlicensed "Part 15 Intentional Radiator" (I
don't know what an "assisted hearing" transmitter is, so I might be
wildly off base), you'll be running afoul of 47CFR15.204(c) if you use
any antenna other than the one supplied with it.

Just trying to help :-)

--
Bert Hyman | St. Paul, MN |

Bert Hyman wrote:

You appear to be posting from the US, so I thought I'd mention that if
this transmitter is an unlicensed "Part 15 Intentional Radiator"

This is a legal device. You can find them at Comtek (www.comtek.com).

I'm just trying to replace the antenna system they are using, which is
a lapel mic with about 48" of shielded cable between the 1/2" connector
and the mic head, with a fixed, shorter high-gain (rubber ducky type)
antenna.

Can anyone help me to accomplish this? What do I need in terms of
the antenna... the exact type?

Thanks.

"scooterspal" wrote in message
...
Bert Hyman wrote:

You appear to be posting from the US, so I thought I'd mention that if
this transmitter is an unlicensed "Part 15 Intentional Radiator"

This is a legal device. You can find them at Comtek (www.comtek.com).

I'm just trying to replace the antenna system they are using, which is
a lapel mic with about 48" of shielded cable between the 1/2" connector
and the mic head, with a fixed, shorter high-gain (rubber ducky type)
antenna.

Can anyone help me to accomplish this? What do I need in terms of
the antenna... the exact type?

Thanks.

'high-gain rubber ducky' isn't that an oxymoron?? rubber ducks are usually
much lossier than full size antennas.

scooterspal wrote:

Bert Hyman wrote:

You appear to be posting from the US, so I thought I'd mention that if
this transmitter is an unlicensed "Part 15 Intentional Radiator"

I'm confused, now.

Their web site (www.comtek.com) shows the newer models operate in the
216-217Mhz band. I have a frequency counter. Is there a way I can make a
wire loop and set the trasmitter near it to pick off the operating
frequency?

Thanks.

(scooterspal) wrote in
:

Bert Hyman wrote:

You appear to be posting from the US, so I thought I'd mention that
if this transmitter is an unlicensed "Part 15 Intentional Radiator"

This is a legal device. You can find them at Comtek
(www.comtek.com).

I didn't say illegal, I said unlicensed.

--
Bert Hyman | St. Paul, MN |

OK. I have tested the frequency and found it to be 75.489Mhz. Should
have done this first, sorry for the confusion. Comtek did make systems
that operated betweeh 72 and 76Mhz. This is one of those.

That said, where do I stand antenna wise?

Thanks!

"scooterspal" wrote in message
...
scooterspal wrote:

Bert Hyman wrote:

You appear to be posting from the US, so I thought I'd mention that if
this transmitter is an unlicensed "Part 15 Intentional Radiator"

I'm confused, now.

Their web site (www.comtek.com) shows the newer models operate in the
216-217Mhz band. I have a frequency counter. Is there a way I can make a
wire loop and set the trasmitter near it to pick off the operating
frequency?

Thanks.

yes, make a wire loop, put the transmitter near it and read the frequency...
just like you said.