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Old 16-02-2012, 14:43   #16
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Re: my family in our dinghy sailing to get breakfast

Yes, I had two HF antennas. A vertical with auto tuner right at the base. Auto tuners are pricey at 100 watt rating, and just downright expensive for higher power levels. A tuner is needed anytime your antenna is not resonant for the operating frequency and does not match the impedance of your radio's output. You would be amazed how well your radio can hear a signal and thus put out a signal when using a antenna resonant for the frequency that you are operating. All a tuner does is fool your radio into thinking the antenna load is both resonant and with a matching impedance.

So this is what I construct for that signal that the away stations report "are you sure your maritime mobile? Your signal is stronger than land based stations in your area". First, commit this to memory 468 / frequency / 2 = 1/4 wave length. The lowest frequency you will use is 75 meter phone @ 3.9 mhz. 438/3.9/2= 60' antenna length. OK, now to antenna design, an inverted vee antenna with downward legs at 90* to each other will have an impedance of 50 ohms, just what your radio wants to see. The center is where you feed the two legs with coax and hoist up your mast with a halyard. Without traps, this would be a single band (75 meter) antenna, but this is where you can have more resonant frequencies by adding traps along the length of those (2) 60' legs. A trap is a coil and capacitor that you design to pass all frequencies except the ones you will be using. You will make (2) traps for each band, 10 meters, 15, 20, and 40 meters. You don't need a trap for 75 meters because your entire antenna was cut for that band. The first trap towards the top, closest to you feed point is for 10 meters which would be for the voice part of the band at 28.6 mhz, so again 468/28.6/2X12= 98.1", and so forth for all the bands you want to operate. How this works is a frequency of 28 mhz sees the first trap as an open circuit, while a frequency of 3.9 mhz will see all the traps you installed as closed circuits, thus using the entire wire length. To get the correct angle between these two legs that you hoisted up your mast, I use a company that makes 40' fiberglass telescoping poles that when nested are only 12' long. These I attached on my old Cal 40 on the bow and stern and just adjusted the angle they stuck out at to dial in my impedance. That is all it takes to have a resonant and impedance matched, multi band antenna that requires no tuner at all, and from my tests are 20~40 db better than a back stay. Back then, nobody made a solid state, high power HF amp, so I built my own. You sure don't need an amp, 100 watts from your radio will do a fine job, but when it comes to my signal, I go all out.
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Old 16-02-2012, 15:02   #17
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Re: my family in our dinghy sailing to get breakfast

The guy that bought my boat in Mexico really wanted the antenna and telescoping fiberglass poles after we used the radio together. Back then all the parts for the antenna were less than $20, the fiberglass poles were $85 each. Now those poles are $250 each, and parts for the antenna around $75. I'll will be building another this winter, and will document with pictures the build and I will start a new thread and share with all.
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Old 16-02-2012, 15:04   #18
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Sigh,

I was born and raised in San Diego, my mum still lives in Coronado. Am a nado grad from '89. Seeing that video make me home sick.

I cut my teeth on coastal cruising in Baka. You guys can't pass up Baka and especially sea of Cortez. Mulege is a must see. If it makes your wife feel better Baja Sur is rated the safest place in all of Mexico. Of all the places I have sailed in the world, the sea of Cortez is by far still my favourite, even above the pacific...

You have a really adorable little girl...
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Old 16-02-2012, 15:13   #19
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Re: my family in our dinghy sailing to get breakfast

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Sigh,

I was born and raised in San Diego, my mum still lives in Coronado. Am a nado grad from '89. Seeing that video make me home sick.

I cut my teeth on coastal cruising in Baka. You guys can't pass up Baka and especially sea of Cortez. Mulege is a must see. If it makes your wife feel better Baja Sur is rated the safest place in all of Mexico. Of all the places I have sailed in the world, the sea of Cortez is by far still my favourite, even above the pacific...

You have a really adorable little girl...
Mulege was my fav, the only year round river in all of Baja. And since it is a bay within a bay, the most clear and pristine waters, with changing blue hues with depth. Desert meets the sea, plus water's edge hot springs all over that cruisers build into baths with rocks, I just loved that place and am trying to talk rebel heart and the missus into visiting. Also great snorkeling and plenty of edible crustaceans.
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Old 16-02-2012, 15:31   #20
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Playa Santispac and Rays Place for sea food on the beach....yummy. I hear Ray has moved off the beach and into town and Eco Mundo burned down?
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Old 16-02-2012, 15:40   #21
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Re: my family in our dinghy sailing to get breakfast

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Playa Santispac and Rays Place for sea food on the beach....yummy. I hear Ray has moved off the beach and into town and Eco Mundo burned down?
I anchored at Playa Santispac, so those nearby hot springs were just great and enjoyed all the small islands in the area.
I haven't been down there in almost 20 years. How time flies when your stuck on ships.
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