Camille,
Not sure if you and
boat are in
England or not....nor what means you have undertaken to reduce / eliminate your on-board RFI....nor what stations / frequencies / times-of-day you have tried, nor if you have a good understanding of
HF radio communications....nor what shore-side RFI your reception is suffering, etc. etc. etc...
So, as you can see all I can offer is general
advice....but, the good news is that I've got 45 years worth of HF
communications experience, including HF WeFax reception experience (starting back in the mid-1970's, with US
Navy WeFax from Norfolk, VA
USA; Rota,
Spain; and others as well, and continuing on to this past month, using NMG,
New Orleans and NMF, Boston...without any issue...DAY and NIGHT!)
1) The first thing I want to assure you of is that it SHOULD BE WORKING!
You SHOULD BE getting excellent WeFax images!!
HF WeFax works, works well, and is used still today by a majority of ocean mariners, daily, worldwide!! (according to a 2012
survey by the IMO/WMO)
And, there is NO need to only try it at night....or only when at sea, away from shore...
Yes, there are frequencies that
work better at night....and many times your
noise level when in port will make reception more difficult....but, it is still VERY do-able (I do it all the time!)
And, if you look at this series of videos, you will see LIVE, real-world reception of HF WeFax (using my Furuno FAX-408), while tied to the
dock, right near shore / with other
boats and houses nearby!
Offshore Weather (including HF WeFax)
https://www.youtube.com/playlist?lis...zdjTJjHlChruyY
http://www.nws.noaa.gov/om/marine/radiofax.wav
2) Next, before you go any further, I need to mention this caveat:
Not being able to "hear" the stations tones and "hear" the noise that is also present on-the-air (whether man-made RFI or natural atmospheric noise), is a hindrance to laypersons actually understanding how the HF system, and WeFax reception in particular, works!!!
{I'm not sure if your blackbox plotter allows you to hear the audio tones (warble / scrape / screech) of the WeFax signals or not....but ALL standalone WeFax machines and most (all?) PC-based WeFax
software allow this, and being able to "hear" these tones is going to go a long way into you, a layperson, being able to easily learn how to use WeFax effectively!}
3) Next, understand that
usually the higher frequencies are used during the daytime and the lower frequencies at night....but, also use the higher frequencies for the longer distances (1000 miles or more) and the lower frequencies for shorter ranges (500 miles or less, day or night)...
If you wish to see some LIVE, real-world examples of how different frequencies propagate over different distances and at some different times-of-day, please look at this video....
4) After
learning what frequency to use, based on the approx. distance you are from the station (200 - 300 miles, versus 2000 - 3000 miles, or more), and on the time-of-day....the next most important step is determining whether you have extraneous
radio noise, called "Radio Frequency Interference" (or RFI) on-board or close-by....
Understand that sources of RFI are ALL around us these days, with modern toys/conveniences of our daily lives contributing to the RFI problem....
Just some of the most notorious RFI producers are:
Dan Foss
refrigeration units, ANY/ALL
battery chargers and inverters, computer
power supplies,
cell phone chargers, Wi-Fi routers, "wall wart"
power supplies, fans, air cond units, digital clocks, digital panel meters, electronic automatic
bilge pump sensors, plasma
screen TV's, many LCD TV's,
computers themselves, some chartplotters, some depthsounders / sonar units,
wind instruments, any/all
electric motors, any/all electronic devices (whether
battery powered or 12vdc powered, or AC Mains powered),
LED lights (actually the voltage regulators in the lights),
radar units, microwave ovens, etc. etc. etc. etc...
The list goes on and on!!
Please note that NOT all of this stuff causes problems for everyone (Thank God!), but just that they CAN and DO cause problems for some sailors!!
Further, not know what the natural atmospheric noise sounds like, versus what RFI sounds like, can be a problem for many new to the world of
HF radio / HF WeFax...
And, while I didn't have a lot of examples to show, I do have some on these videos....
Please have a look...
Natural Atmospheric Noise
Man-Made Noise / RFI
5) NAVTEX....
NAVTEX is very reliable and will
work well as long as you are within 200 miles (or so) of a NAVTEX station....day or night, rain or shine...
So, if your NAVTEX only occasionally works, this is a sign of some serious on-board RFI issues!
{And a clear indication of what I've been saying for decades...just because someone gets paid to sell/install
electronics, doesn't mean they know what they are doing!!!
I've been doing this (not
marine electronics) professionally for > 30 years....and the number of complete idiots that make an excellent living in this industry is staggering!!!
You should have NEVER even been asked to pay your final bill until every part of every system was demonstrated to you and you were clearly instructed in how-to use every feature!
And, since you wrote
"The Weatherfax has never worked well with fuzzy pictures, often unreadable. the Navtex sometimes works.", it's clear that nobody ever showed you how all of this works!!
Absolutely criminal! }
Camille, please see my specific answers / comments here in red...
Quote:
Originally Posted by Camille1
i have a Furuno Fax 30 Weatherfax with Navtex Unit feeding into my Blackbox Plotter.
The Weatherfax has never worked well with fuzzy pictures, often unreadable. the Navtex sometimes works.
It should be working good....see above for details...
I have tested the unit in a number of locations in NE America and in NW Europe with little variation in picture quality frequently unreadable.
It should be working good....see above for details...
The unit has been returned to Furuno who say it is in good working order. i have replaced the Fax 5 Antenna preamplifier
You do NOT need the FAX 5 antenna, nor pre-amp, to do any testing....just a length of copper wire, about 15' - 35' long, plugged into the FAX-30's antenna jack, and strung up temporarily with a flag halyard, etc...
(note that my WeFax receive antenna is an insulated aft lower shroud, about 22' long....shared as my HF-DSC receive antenna....and has worked well for > 12 years on my current boat!!)
But, since you mention the FAX-5 antenna....WHERE it is placed/installed, and WHAT is close-by this antenna, can be a VERY IMPORTANT issue / cause serious reception problems!!!
and I have turned off all other electrical equipment to eliminate any possibility of interference.
Understand that "turning off" other equipment usually doesn't eliminate the RFI from them, you must remove the power from them entirely in order to test this!
The Fax 30 is earthed to a ground plate. The location of the antenna is on a steel post at the pushpit; I have tried it elsewhere to no avail.
Sounds like three very common problems:
a) RFI
b) Wrong station / wrong frequency for your distance and time-of-day
c) Lack of user education on how it works
PLEASE do NOT take offense....you are not supposed to know all of this stuff....the guy selling/installing it MUST know it, and they are supposed to TEACH this to you!!
So, no worries here! 
Can anyone help please? |
I do hope the above helps...
But, please WATCH the videos and listen to the WeFax tones.....
https://www.youtube.com/playlist?lis...zdjTJjHlChruyY
http://www.nws.noaa.gov/om/marine/radiofax.wav
And, then tell me:
a) WHERE you and boat are at...
b) Whether you can "hear" the HF WeFax audio tones (warble / scrape / screech)
c) What RFI tests you may have already done, etc.
Also, be sure to watch these videos, for even more
Marine HF communications info / demonstrations...
Marine HF Comms
https://www.youtube.com/playlist?lis...ZDo_Jk3NB_Bt1y
HF-DSC Comms
https://www.youtube.com/playlist?lis...ga2zYuPozhUXZX
Icom M-802 Videos
https://www.youtube.com/playlist?lis...rC-8QKVyMb4tVr
Fair winds..
John
Linear Mode
Recent Discussions