Antenna Sharing for Marine - Weather Fax/NavTex and SSB-DSC
 

I have an ICOM M-802 SSB and a Furuno FAX-30 (Weather Fax Reciever) onboard
my boat. The ICOM M-802 has a dedicated receive port for DSC Receive. Can
I share the FAX-30 Antenna with the DSC receive port of the SSB? if so what
coupler should i use? (The SSB Xmit/Rec antenna is 3meters away)

Bill

Antenna Sharing for Marine - Weather Fax/NavTex and SSB-DSC
 

forgot to mention: the freq of theWeather Fax is the same as the SSB 2-25
MHZ

Bill


"Wet-n-Wild Bill" wrote in message
...
I have an ICOM M-802 SSB and a Furuno FAX-30 (Weather Fax Reciever) onboard
my boat. The ICOM M-802 has a dedicated receive port for DSC Receive. Can
I share the FAX-30 Antenna with the DSC receive port of the SSB? if so what
coupler should i use? (The SSB Xmit/Rec antenna is 3meters away)

Bill

Antenna Sharing for Marine - Weather Fax/NavTex and SSB-DSC
 

Wet-n-Wild Bill wrote:
forgot to mention: the freq of theWeather Fax is the same as the SSB 2-25
MHZ

Bill


"Wet-n-Wild Bill" wrote in message
...

I have an ICOM M-802 SSB and a Furuno FAX-30 (Weather Fax Reciever) onboard
my boat. The ICOM M-802 has a dedicated receive port for DSC Receive. Can
I share the FAX-30 Antenna with the DSC receive port of the SSB? if so what
coupler should i use? (The SSB Xmit/Rec antenna is 3meters away)

Bill




The FAX-30 can handle a variety of antennas. Do you have the FAX-5
active antenna? You can probably connect the M-802 DSC port and the
FAX-5/FAX-30 together through a simple coax tee connector. There is not
likely to be any interaction between the devices. If interactions should
arise, the simplest solution is a coax switch. The switch would be left
in the DSC position except when using the FAX-30.

As a precaution, you might contact Furuno and get their opinion. I would
think the "dual use" potential for the FAX-5 antenna would be a selling
point for Furuno and cause them to give your question a serious
response. The question of a separate DSC antenna for the M-802 is likely
to be around for a while.

Good luck.

Chuck

Antenna Sharing for Marine - Weather Fax/NavTex and SSB-DSC
 

Chuck

Thanks! I was thing about a TEE and was concerned about the front end of
each receiver.

Yes i do have the FAX-5 antenna installed.

And a coax switch may be the next option before mounting another whip!

What about a discone antenna, other than looks onboard a boat!

Bill


"chuck" wrote in message
ink.net...
Wet-n-Wild Bill wrote:
forgot to mention: the freq of theWeather Fax is the same as the SSB
2-25 MHZ

Bill


"Wet-n-Wild Bill" wrote in message
...

I have an ICOM M-802 SSB and a Furuno FAX-30 (Weather Fax Reciever)
onboard my boat. The ICOM M-802 has a dedicated receive port for DSC
Receive. Can I share the FAX-30 Antenna with the DSC receive port of the
SSB? if so what coupler should i use? (The SSB Xmit/Rec antenna is
3meters away)

Bill




The FAX-30 can handle a variety of antennas. Do you have the FAX-5 active
antenna? You can probably connect the M-802 DSC port and the FAX-5/FAX-30
together through a simple coax tee connector. There is not likely to be
any interaction between the devices. If interactions should arise, the
simplest solution is a coax switch. The switch would be left in the DSC
position except when using the FAX-30.

As a precaution, you might contact Furuno and get their opinion. I would
think the "dual use" potential for the FAX-5 antenna would be a selling
point for Furuno and cause them to give your question a serious response.
The question of a separate DSC antenna for the M-802 is likely to be
around for a while.

Good luck.

Chuck

Antenna Sharing for Marine - Weather Fax/NavTex and SSB-DSC
 

Wet-n-Wild Bill wrote:
Chuck

Thanks! I was thing about a TEE and was concerned about the front end of
each receiver.

Yes i do have the FAX-5 antenna installed.

And a coax switch may be the next option before mounting another whip!

What about a discone antenna, other than looks onboard a boat!


Yeah, it'd be great! But unless you are on an aircraft carrier or
battleship, you couldn't fit a discone for HF on a small cruising boat.
The smaller VHF discones wouldn't help you much with HF weatherfax or HF
DSC reception.

Chuck









Bill


"chuck" wrote in message
ink.net...

Wet-n-Wild Bill wrote:

forgot to mention: the freq of theWeather Fax is the same as the SSB
2-25 MHZ

Bill


"Wet-n-Wild Bill" wrote in message
...


I have an ICOM M-802 SSB and a Furuno FAX-30 (Weather Fax Reciever)
onboard my boat. The ICOM M-802 has a dedicated receive port for DSC
Receive. Can I share the FAX-30 Antenna with the DSC receive port of the
SSB? if so what coupler should i use? (The SSB Xmit/Rec antenna is
3meters away)

Bill




The FAX-30 can handle a variety of antennas. Do you have the FAX-5 active
antenna? You can probably connect the M-802 DSC port and the FAX-5/FAX-30
together through a simple coax tee connector. There is not likely to be
any interaction between the devices. If interactions should arise, the
simplest solution is a coax switch. The switch would be left in the DSC
position except when using the FAX-30.

As a precaution, you might contact Furuno and get their opinion. I would
think the "dual use" potential for the FAX-5 antenna would be a selling
point for Furuno and cause them to give your question a serious response.
The question of a separate DSC antenna for the M-802 is likely to be
around for a while.

Good luck.

Chuck

Antenna Sharing for Marine - Weather Fax/NavTex and SSB-DSC
 

"Wet-n-Wild Bill" wrote in message
...
forgot to mention: the freq of theWeather Fax is the same as the SSB 2-25
MHZ

Bill


"Wet-n-Wild Bill" wrote in message
...
I have an ICOM M-802 SSB and a Furuno FAX-30 (Weather Fax Reciever)
onboard
my boat. The ICOM M-802 has a dedicated receive port for DSC Receive.
Can
I share the FAX-30 Antenna with the DSC receive port of the SSB? if so
what
coupler should i use? (The SSB Xmit/Rec antenna is 3meters away)

Bill




http://www.furuno.com/Furuno/Doc/0/A...FAX30%20Operat
or%27s%20manual%20d1%201.22.2003.pdf

They talk about a coupler in Section 7, but are not specific. As I dislike
t-connectors on principle, I would use a 50-ohm power divider. They
correspond to the action of a TV cable splitter but an actual TV cable
splitter would not perform well at HF and below You can build your own in a
metal project box, using a Y configuration with a 25-ohm carbon resistor in
each leg to maintain some semblance of impedance matching. Maybe you can
find an old TV cable splitter that you can gut for the purpose. For
receive-only, the antenna length is not critical. I recall Navtex specifies
a whip antenna of several meters; Navtex is on two freqs near 500 KHz, so
it's not far from the AM broadcast band. Hm-m-m ... What does a car radio
antenna look like???

Good luck.

Antenna Sharing for Marine - Weather Fax/NavTex and SSB-DSC
 

Sal M. Onella wrote:
"Wet-n-Wild Bill" wrote in message
...

forgot to mention: the freq of theWeather Fax is the same as the SSB 2-25
MHZ

Bill


"Wet-n-Wild Bill" wrote in message
...

I have an ICOM M-802 SSB and a Furuno FAX-30 (Weather Fax Reciever)

onboard

my boat. The ICOM M-802 has a dedicated receive port for DSC Receive.

Can

I share the FAX-30 Antenna with the DSC receive port of the SSB? if so

what

coupler should i use? (The SSB Xmit/Rec antenna is 3meters away)

Bill




http://www.furuno.com/Furuno/Doc/0/A...FAX30%20Operat
or%27s%20manual%20d1%201.22.2003.pdf

They talk about a coupler in Section 7, but are not specific. As I dislike
t-connectors on principle, I would use a 50-ohm power divider. They
correspond to the action of a TV cable splitter but an actual TV cable
splitter would not perform well at HF and below You can build your own in a
metal project box, using a Y configuration with a 25-ohm carbon resistor in
each leg to maintain some semblance of impedance matching. Maybe you can
find an old TV cable splitter that you can gut for the purpose. For
receive-only, the antenna length is not critical. I recall Navtex specifies
a whip antenna of several meters; Navtex is on two freqs near 500 KHz, so
it's not far from the AM broadcast band. Hm-m-m ... What does a car radio
antenna look like???

Good luck.



Impedance matching shouldn't be an issue for the OP since he is using an
active antenna. A short whip at at 500 kHz presents a terrible mismatch
to a "50 ohm" receiver input so the active antenna matches impedance,
usually with an FET source follower, and may provide gain as well. The
more interesting question is how the active antenna "works" over the
entire HF range without retuning!

The potential problem with a tee is that it provides no isolation
between the two receivers. But I doubt that would be a problem. All it
takes is a couple of dollars and a few minutes to find out.

Chuck