VHF / UHF HAM Radio Antenna ... and AIS?

[s/v Jedi]

Originally Posted by colemj

The Diamond dual band antenna on our mast before the lightning strike had a loading coil and regular PL259 connector and did not need the mast for the ground. So does the spare we have on board (you should have mentioned all this earlier Nick - I could have saved you some shipping costs!).

Of course, mounting the antenna to the mast connects the ground to the mast - similar to most common metal whip VHF antennas with loading coils.

Mark

Edit: I just caught that you specified the Diamond mobile antenna, and I think I am talking about a different Diamond model.

Hi Mark,

I guess a male PL259 sticks out from the bottom of your antenna? If not, I would like the model number

Shipping costs? moi? I don't pay shipping costs Just got the tracking info.. it's on the way to Miami!

ciao!
Nick.

[colemj]

It used a F-F coupler. I don't know the model number, but I bet the old antenna is still in the yard over where our mast was sitting!

Mark

[Cpt Pat]

Just to throw this into the mix... here's the solution I used:

Kenwood TM-D710 ->
Alpha Delta A/B Switch -> 1/2 wave antenna at mast
AIS Class B -------->


MT-AIO APRS ---> 1/4 wave (19 inch) antenna on the bow pulpit (for a ground plane)


Standard Horizon Marine Band HT (with DSC) ---> 1/2 wave antenna on the stern toerail


Both 1/2 wave antennas require no ground plane and are Shakespeare "squatty body" antennas.

The advantages were:

1) I seldom use the Kenwood on 2 meters while underway. If I ever need 50 watts ERP and 40 miles line-of-sight while underway, it's probably an emergency and I can switch on the Kenwood and use it on the marine band. Otherwise, the AIS gets the range and the preferred antenna. There's no problem with the AIS transponder seeing infinite VSWR (the AIS specification says it must tolerate an antenna dead short/open). It just keeps trying until I throw the A/B switch back to it. I find the squatty body antenna works great on both 2m and 70 cm when I need it.
2) I hear way too much on the Marine HT here in the San Francisco Bay area using the masthead antenna. I really don't need to receive other vessel's hails to a portmaster 40 miles away. Channel 16 is too chatty and a real distraction with that much receive range. But when I'm offshore - I really DO want to know about a container ship that's closing on me at 30 knots that's 40 miles away.
3) If I ever need to, I can hit the Big Red Button (DSC Distress) on the HT, and still talk on channel 16 with the Kenwood while the HT repeats the DSC distress call every 4 minutes (until acknowledged). The Coast Guard antennas are on towers with good line of sight to my antenna 5 feet above the water, and any vessels that can't hear the DSC distress call are probably to far away to provide any assistance.
4) The APRS, AIS, and HT antennas have the maximum physical separation.

All three antennas have lightning suppressors (Alpha Delta) and are bonded to a ground strap that runs the length of the bilge and up to the mast base (where the masthead antenna coax terminates at a lightning suppressor). The ground strap is then terminated at a 1 square foot, 1/8 inch think zinc plate that I toss in the water at the slip/anchor -- and that I also toss in the water when underway when lightning is anywhere nearby.

The solution works for me. YAMMV.

BTW, I tried an antenna splitter, and I was very disappointed with its performance. You can't get somethin' for nothin'.

[bobconnie]

Gee and I thought I was an outlaw for useing a 25 watt ssb reworked for the cb bands LOL I still have my old ssb 150 but Im still trying to understand the fancy mapping programs all you guys use !! I guess Im just gonna have to understand Im a Non electronic nerd!! just an old sailor who better stick with what I know LOL But that big radio do sound good !!

[s/v Jedi]

Okay, all the goodies are in: two handhelds and the set for the nav station. I'm impressed with the antenna system with that thin teflon coax for easy pull through ducting etc. but still rated for 500W continuous.

I charged the batteries of the two handhelds and got their GPS fired up and even APRS broadcasting position info and the other receiving that and able to do a GOTO to the other etc.

Now I need to do the mods... to allow them broadcast on VHF channels.

ciao!
Nick.

[s/v Jedi]

Modified the first TH-D72 handheld for VHF and upgraded it's firmware (it has an USB port). Had to remove 2 invisibly small diodes and do full reset. It now transmits from:

136-174 MHz and
410-470 MHz.

Downloaded software to program the radio. Bad news is that I couldn't find marine VHF band plan as download for this software, so had to type it all in. Good news is that I now have every channel that exists in the world.

To be continued...

Nick.

[s/v Jedi]

On-line in APRS now with just the handheld... no need for the repeater

Google Maps APRS

I can clearly see how AIS is a straight copy of the APRS system.

I put the external antenna for the D710 radio on a handheld and immediately make 65km links... with 5 Watts With the rubber duck I still get on-line via a closer repeater.

prepping for install of the D710 now.

ciao!
Nick.

[s/v Jedi]

Modified the 710 tonight... it's also a 50W marine VHF now
It was easier than the handhelds... one small wire jumper and one 0 Ohm resistor had to be removed. The resistor was just visible so slightly better than the invisible diodes in the handhelds. It's also much easier opening the 710 to get to the circuit board.

It is basically the same software as the handheld but the controls are a bit different and there's some functions that I just learned on the handheld but can't find on the 710 yet.

Now I need to connect my NMEA2000 to it's NMEA0183 port I better get my converters ready I also need to install that antenna but I can put it on marine VHF antenna for now. Need GPS data so that I can start beaconing


ciao!
Nick.

[IslandHopper]

So Jedi do you offer your skills to the cruising community.....http://www.cruisersforum.com/forums/...ers-80133.html ....could be a good little earner.....

[s/v Jedi]

Originally Posted by IslandHopper

So Jedi do you offer your skills to the cruising community.....http://www.cruisersforum.com/forums/...ers-80133.html ....could be a good little earner.....

I offer advice... for free I'm retired so I only work on my own boat

The 710 is online now: Station info for KI4CIS-9

Looks like it works just fine on the marine VHF whip but I didn't put the SWR meter on it yet... The repeater that picks me up is close but I heard at least 4 or 5 repeaters on my first beacon.

I had to enter my GPS position by hand for this, hope to have the NMEA hooked up tomorrow.

ciao!
Nick.

[IslandHopper]

Originally Posted by s/v Jedi

I offer advice... for free

ciao!
Nick.

Your a champion mate!

[downunder]

Originally Posted by IslandHopper

Your a champion mate!

+2

[s/v Jedi]

Thanks guys

I finally got it to work. I've been mad at Mark aboard Reach all day. I could not get the GPS link to the new radio to work and a couple months ago Mark had the same issue. He asked me to help and after so much trouble it finally started working but the bug has jumped over to Jedi now

I really hate this: I had to install another, older 0183 GPS to get it to work. I have 2 conversions from N2K to 0183 on RS232 going but neither does output the correct sentences for the radio

I had almost sold that GPS too, which would have put me down without hope haha.

Here's a nice picture:


Let me talk about it a bit so that some readers here might start to understand what is happening; This radio is actually two radios in one. On the left side of the display you see radio A, currently tuned to 145.010 MHz and on the right side you see radio B which is tuned to marine VHF channel 12 @ 156.600 MHz. I have timed this picture to show that both A and B are receiving a signal simultaneously VHF-12 is the local Cristobal Signal Station traffic control for Colon and 145.010 is the HAM 2m APRS frequency in Panama.

The top right of the display shows BCON GPS which indicates that the radio is receiving data from my GPS and is beaconing it to APRS. This is why you can now see Jedi as KI4CIS-9 on Google Maps APRS

This is much like a marine VHF with built in AIS transponder (but APRS is not directly compatible with AIS).

You can also see "PTT CTRL" on the radio-B (right) side of the display which means that my controls and microphone are linked to that radio. I can pickup the mike and talk on VHF channel 12 regardless of what APRS is doing.

This works 100% now but I must find a solution to the GPS requirements (different converter I hope) and then mount everything. I'm also on my main VHF antenna right now which prevents me from using the 70cm band of the radio, so I must install the other antenna too.

I really like the D710 radio. I can receive so much incl. aircraft band and all the way up to 1.2GHz. I am receiving an APRS repeater from Vulcan Baru on 145.010 which is 291km away !! Okay, it's 3,300 meters above sea level but still it's impressive performance for VHF. I am on medium power which is 10W for this radio and stations 65km away receive me. High power option is 50W and low power is 5W.

to be continued . . .


Nick.

[s/v Jedi]

And here some if the power of the system gets unveiled: I just sent my first email message via Winlink with just this radio, no computer used for this!

http://www.findu.com/cgi-bin/msg.cgi?call=KI4CIS-9

cheers,
Nick.

[s/v Jedi]

Here's the next feature at work: real time weather info:



ciao!
Nick