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SSB Antennas

V

Vito

Jan 1, 1970
0
Tests of mobile antennae in the Amateur Radio 75 meter band (4MHz) yielded
the following results:

* Well-designed Bugcatcher or Screwdriver with top hat 0 dB reference
* Bugcatcher or Screwdriver with no top hat -3 dB
* Hustler or Outbacker -9 dB
* Hamstick -12 dB
* Whip with autotuner -14 dB

This suggests that the common insulated-backstay-with-autotuner used on
sailboats could be improved by adding a capacitive top hat immediately below
the upper insulator and/or a tapped coil in parallel (ie around) the lower
insulator to tune whatever length of antenna one can physically accomodate
to resonate on or near the Marine frequencies of interest, such as 2182 MHz.
Has anyone any experience doing so?
 
B

Bruce in Alaska

Jan 1, 1970
0
Vito said:
Tests of mobile antennae in the Amateur Radio 75 meter band (4MHz) yielded
the following results:

* Well-designed Bugcatcher or Screwdriver with top hat 0 dB reference
* Bugcatcher or Screwdriver with no top hat -3 dB
* Hustler or Outbacker -9 dB
* Hamstick -12 dB
* Whip with autotuner -14 dB

This suggests that the common insulated-backstay-with-autotuner used on
sailboats could be improved by adding a capacitive top hat immediately below
the upper insulator and/or a tapped coil in parallel (ie around) the lower
insulator to tune whatever length of antenna one can physically accomodate
to resonate on or near the Marine frequencies of interest, such as 2182 MHz.
Has anyone any experience doing so?

Most noncommercial boaters do not have the expertiese to understand,
let alone install, what you are describing. Most commercial vessels
have enough Mast Height to accommodate a "Total Antenna Length" of 75 ft
so that common autotuners can resonate the system to 2182 Khz. On
SOLAS Required Vessels MF and HF Antenna Systems are designed to
be resonate on all the specific SOLAS Required Frequencies and are
TESTED and Logged once a year by Licensed Marine Radio Tech's.

Bruce in alaska
 
G

Gary Schafer

Jan 1, 1970
0
Yes the top hat would help out on 2 and 4 mhz frequencies. Problem is
where to put it where it is not in the way.

A loading coil on the stay would also help out but it would work even
better if it was up high nearer to the top of the stay.
Problem is that usually only one antenna is available for all bands on
a boat. At the higher frequencies that loading coil would act as a
choke and effectively disconnect the upper portion of the antenna.
Which may not be all that bad if there is sufficient length below the
coil for the higher frequencies.

The other problem that you may run into is that the auto tuner may not
like the impedance it sees. Most auto tuners do not like to see a
resonant antenna near 50 ohms. But on 2 mhz it would probably help a
lot.

Regards
Gary
 
B

Bruce in Alaska

Jan 1, 1970
0
Doug Dotson said:
Not familiar with a Marine Radio Tech License? I have a GROL
with radar Endorsement and a GMDSS/M, but I'm not aware
that is what you are referring to. The NMEA has a certification
process but that's not really a "license" per se.

Doug, k3qt
s/v Callista

Licensed Marine Radio Tech is a person who has an FCC GROL/w
RADAR/GMDSS-M and is licensed to maintain Maritime Mobile Radio Service
licensed systems aboard US flagged Vessels. The SOLAS Requires that
Title III Part II, and title III Part I Vessels be inspected on an annual
basis and that inspection by a Licensed Marine Radio Tech, be logged in
the Vessel Station Log and a renewed SOLAS Certificate be Issued and
Posted for Public Inspection. In the passed, these inspections were
done by FCC Field Agents, and the SOLAS Certificates, Bridge to Bridge
RadioTelephone Certificates, were issued by the FCC Field Agents, on
completion of the inspection. A similar inspection of Title IIi Part
IIi Vessels needs to be completed every 5 years for those class vessels,
and is done, now, through the same method.

Bruce in alaska
 
B

Bruce in Alaska

Jan 1, 1970
0
You got it, Doug. Did you have 1st Phone before the shame of the GROL
was thrust upon you? I keep my 1st Phone with Radar in a frame over
my desk. I keep my GROL in the back of the file cabinet so noone can
see I have a CB license...(c;

You had to KNOW something to pass the 1st Phone, not just memorize the
test questions handed to you on a silver platter......It meant
something.

I added GMDSS maintainer and operator, but that was just a rote
memorizer test any fool who can read could pass, like the GROL.....

I actually cheated on the GMDSS tests. I'm a Dale Carnegie graduate.
DC teaches you how to memorize a whole magazine by associating each
page with a visualization. It was the most important thing I got out
of the course.
One - Run
Two - Zoo
Three - Tree
Four - Door
Five - Hive
Six - Sticks
Seven - Heaven
Eight - Grate
Nine - Wine
Ten - Den

I can still hear my instructor harping the first 100 visualizations on
us...(c; It's how I remembered the answers to the question bank,
which is easy after you memorize the ad on page 49 of National Review
for DC class.


Larry W4CSC

Yep, I feel the same way about my GROL, as I keep my First Phone, and
First Graph/Aircraft Endorsement up on the wall, and I only keep the
Pocket version of my Lifetime GROL/Radar/GMDSS-M-O in my wallet.

Bruce in alaska
 
B

Bruce in Alaska

Jan 1, 1970
0
The only thing the GROL is useful for, now, is marine and aviation
radio. The only reason it's still in existence is the ITU requires
it.



Larry W4CSC

Yep, every CB nut with a screwdriver can now fiddle with any Land Mobile
Radio, Broadcast Transmitter, Microwave System, and Public Safety Radio
System, in the country. And folks wonder why interference complaints
are doubleing every three years.

Bruce in alaska
 
B

Bruce in Alaska

Jan 1, 1970
0
Doug Dotson said:
and dispatches licensed techs

Nope Doug, no License Required anymore. Knowledgable Tech's recomeended
but not even required. That's why I got out of the Broadcast Business
35 years ago. To many Carneigie, and Elkins, First Phone's showing up,
and getting OTJ Training on my license as Chief Engineer. There's no
such thing as an Automated 50,000 Watt AM Transmitter. When those
puppy's decide to melt down, they do it in a hurry, and usually with
lots of sparks and steam from the liquid cooling systems. Usually
the finals are pulled at 50% of rated time, but nowdays with skimpy
maintaince money, owners are pushing that out to 80% and catastophic
failure is happen a lot more often. Reminds me of a very cold January
Night when KRAB-FM's antenna took a hell of a wet snow load, and
unbalanced the two 5Kw finals explosivly. I came around the corner
and the DJ on duty was out in the street with a bunch of steaming holes
in the snow where hot final Parts had melted down through the snow.
Took the consulting engineer and I, 8 hours to rebuild the final cage
(Lots of plumbing parts) and get it back on the air.

Bruce in alaska
 
L

Larry

Jan 1, 1970
0
You got it, Doug. Did you have 1st Phone before the shame of the GROL
was thrust upon you? I keep my 1st Phone with Radar in a frame over
my desk. I keep my GROL in the back of the file cabinet so noone can
see I have a CB license...(c;

You had to KNOW something to pass the 1st Phone, not just memorize the
test questions handed to you on a silver platter......It meant
something.

I had a 1st as well, but frankly thought the 2d was a good deal harder. If
nothing else, it was a lot longer! I recall the 1st was 50 questions (and
it seems like it was mostly law) and the 2d was 200 questions. I passed
them both, but I recall spending a long time on the 2d. Never did the
GMDSS/M or radar.

I thought that after the FCC went to General Commercial that NABER or
someone like that handled endorsements for a while, but then they gave that
up. Do you remember what happened to that stuff?
 
G

Gary Schafer

Jan 1, 1970
0
The nitrogen was for the transmission line.

Regards
Gary
 
T

Tuuk

Jan 1, 1970
0
Ok guys,, what's your comments on the 2m homebrew antenna? Anyone build one
and had a particular preference or reasons why one over the other?

Thanks
 
B

Bruce in Alaska

Jan 1, 1970
0
Doug Dotson said:
I misstated my thought. I mean't "qualified techs" since a license is
no longer required.
The question was as to the reason that a license is no
longer required. Larry seems to suggest that it is because very
few blacks are able to get a 1st Phone. My recollection is that
it is because detailed technical knowledge is not required to safely
and legally operate a transmitter these days.


Maybe up in Alaska. But I'm pretty sure that is not the case in general.


My years in the process control industry make me pretty confident that
the computer can sense and react to pretty much anything unusual faster
than the most skilled engineer/tech. Not to say that an on-site person is
not an asset because once the computer has either shut things down or
reduced power to save the transmitter, someone has to diagnose and
fixed the problem.


A good SCADA system should have sensed the impending problem and
may have been able to save the day. But, as you say, some failures are
so sudden that there is no way out.

Well I have now been updated on Broadcast Transmitters...... thanks
Larry. It has been a few years since I inspected an AM Broadcast Station
and the one's I did do were out in the small communities of alaska.
I got out of the Broadcast Industry as an Engineer, many years ago,
so it isn't to suprising that I am a bit out of date on the technology.
Oh well, age gets us all eventually. Thank goodness Marine Radios
are still using 1990 technology, cause I still have a bit of a handle on
them.

I also talked to my buddies at SEA, and they are just coming back
into production on their SEA157 VHF Radio's and even a few of the SEA235
MF/HF Radio's. This is very good news for the thousands of folks who
have SEA Products onboard. I also had a chance to talk to Mark Johnson
of ShineMicro about AIS. He is really big into this new (to me) Position
Reporting System now being mandated for ships of 65Ft in the US.
Way cool stuff if you got the money, and still way cool when the ClassB
stuff for Volitary Compliance comes out later this year.


Bruce in alaska
 
B

Bruce in Alaska

Jan 1, 1970
0
Doug Dotson said:
Then I guess I R 1. But what is the second part of your statement? The part
that
reads "and is licensed to maintain Maritime Mobile Radio Service
licensed systems aboard US flagged Vessels"? What is this license? Who
issues it?


I remember all the mumbo-jumbo from the GMDSS license. So is the GMDSS/M
license what makes one all of these fancy titles or is there some other
authority that grants these lofty titles.

Yep, your R one, and with this little slip of paper, you can now LEGALLY
adjust Marine & Aircraft Radio Systems so as to make them compliant with
Parts 80 & 87 of the FCC Rules and Regulations. Oh yea, you need an FAA
Certificate if you mess with Aircraft systems in actual Aircraft, or you
need someone who has an FAA Certificate to sign off on any work on
Aircraft Radio's.

All that said, there really isn't much to adjust anymore unless your
working with some of the older MF/HF Radio's around. Mostly just
setting the Master Osc. on frequency, and then setting the power output,
and your done these days.

Bruce in alaska
 
J

Jack Painter

Jan 1, 1970
0
Larry W4CSC said:
Every boat should be on APRS on both HF and VHF through assigned VHF
and HF channels. Every packet APRS station can be a repeater for ever
other APRS station, far extending the range of the individual
stations. Some stations are connected through the internet to the
national APRS servers hams have setup, including www.findu.com. It's
all voluntary, of course, in true ham radio tradition.

For the marine application of APRS, visit Bob Bruninga, APRS'
inventor, at the Naval Academy website:
http://web.usna.navy.mil/~bruninga/aprs.html
He tracks the Academy's boat fleet with APRS on them. I fixed one of
the APRS stations on an Academy yacht when it was in Charleston a few
years ago to put it back online with APRS on VHF and HF. It keeps our
Midshipmen from being too lost...(c;

Larry, are you aware of any "findu" type charts that are adaptable to APRS?
Mapquest "maps" display a poor graphic when plotting a vehicle on long
bridges like the type that interlace the Hampton Roads Va area. It's not
that the position reported from GPS is inaccurate, but a graphic
representation becomes muddled when bodies of water are shown by Mapquest.
We're thinking the mapquest maps would accordingly be of little use in this
area as a result, but have not actually tried the equipment from a boat yet.

Jack
Va Beach Va
 
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