First off tks to Adam and rtlsdrblog for your comments and suggestions. Every idea spawns at least 3 more...
Would love to get an AirSpy probably one of the new "mini" I know gqrx supports them, but not too sure about rtl_fm. Rtl_fm is still the software of choice (so far) because its extensive command line interface allows for easy bash scripting of automatic unattended operations. As you are aware, and rtlsdrblog pointed out, the bandwidth available on the boat (off shore) is not adequate or reliable enough for any live stream at this time. If we can get this whole setup to run on a Pi(3) in the future, with a small enough physical footprint we may be able to talk the City Marina into letting us hang it off their tower which will also give us good access to a reasonable bandwith internet connection.
I don't think our goals of providing a single vhf net one time a day meets the general criteria of WebSDR or their audience, but I love the group tuners around the world. For us, much easier to provide the bandwidth from a dedicated internet server to a larger audience than relying on the uplink bandwidth for multiple users. We are a fixed (156.425Mhz) frequency operation for a max of 1.5 hrs a day. Good idea though.
Thanks for the pointer to the tee-stub notch filter. Quick and dirty and can probably scrounge most of the parts around the harbor. Looks pretty straight forward. The interfering transmissions are pretty clear while running gqrx.
A high pass or bandpass filter is not beyond my construction abilities. Plenty of PC board and soldering experience. Where I need the guidance is after running one of the available online "calculators" how close is close enough in the capacitors and inductors... Mouser and etc have an ass of them, but how close to 31.032 nano henrys do I need to be to be close to the freq I want. Hope to find a local (or not so local) who does this all the time who can say "Ehhh that's close enough, don't worry bout it"
Still trying to duplicate gqrx settings (gui) in rtl_fm Gqrx is easier to adjust on the fly, but the documentation about what the settings in the gui really mean to the dongle are not really all that good. Poke and hope slowly. When I think I have an optimum gqrx setup maybe one of you all (or someone lurking) can help me transpose that to the rtl_fm command line switches.
If it were simple, it wouldn't be near so much fun. Tks again for the suggestions and the help.
More to follow
If your are interested in listening to a sample on the prototype site (mp3 recorded via udp stream and uploaded via sftp)
Sounds like it needs a little more bandwidth to me as well as a bit of gain and less squelch. Will try again tomorrow
And yes thats me as net control...