top-fed SSB backstay antenna??

[Gordon Wedman]

Over the holidays I killed some time looking through a few back issues of
Cruising World. In the April 1986 issue a boat-based ham operator said he
used a top-fed backstay antenna with excellent results AND he had no in-hull
ground plane. He said he connected the shield from his feed wire to the
mast-side of the backstay and this allowed the mast and all the standing
rigging to act as a ground plane. He didn't say anything about using
stand-offs between the feed wire and the mast. I would think you would get
a lot of signal loss over that much length if you didn't use stand-offs?
If a person could put up with the appearance and make sure the whole set-up
didn't get torn down by sails/running rigging, would this really give good
performance? I don't recall reading about this type of set-up so I guess
its not too common on recreational boats but maybe it could be worth
considering in some situations?

 

[Doug Dotson]

That's a slightly different animal. It is acts essentually like a dipole
which is a balanced antenna. Balanced antennas do not need a
ground plane. Standoffs are not needed because the mast is part of
the ground side of the antenna which is what the shield on the coax
is. I experimentd with a real dipole by stretching it between the masthead
and the radar arch. It was fed in the middle with a balun. Worked well, but
keeping the feedline out of harms way proved to be a problem.

If the antenna in question was fed with coax, a balun would be
desirable.

Doug, k3qt
s/v Callista

 

[Gordon Wedman]

Thanks Doug
So it would work well as an antenna for marine SSB?
If so I'm a bit surprised more people don't use this instead of trying to
achieve that elusive ground plane in the hull. Sounds like you could just
run the feed wire inside the mast if you don't need standoffs and the whole
installation would be pretty slick.

 

[Doug Dotson]

Well, the tuners that come with marine sidebands (AT-140 etc) are
designed for end-fed long wires. Also, dipole lengths are specific to
the band one is working. Multiband operation would require some sort
of traps in both the backstay (sort of easy) and also matching traps
in the mast (really hard!). So in short, you can eliminate the ground
plane, but you also inherit less flexability. You also need to get an
antenna tuner that can tune a dipole. There has been some discussion
about tuning the entire rig (W4CCC) but I have no experience in
that area. Larry (W4CCC) also seems to have vanished from this
forum. I hope it was not a result of RF burns or that someone pointed
out there is no record of his ham licence in the FCC database

The elusive groundplane in the hull is a myth. Run foil from the tuner and
radio
to a thruhull and you are done. Make sure the thruhull is not part of a
bonding
system, it must be isolated. I wrapped the foil around a cockpit scupper
seacock and secured it with a hose clamp. I get excellent signal reports
and had no problems doing email from The Bahamas to dozens of land
station inside the US and Canada. Let me know if you want to arrange
for a QSO to check out my signal.

Doug, k3qt
s/v Callista

 

[Doug Dotson]

Oh, and I forgot. I don't use an insulated backstay. I have a 23' whip
mounted
on the transome.

Doug, k3qt
s/v Callista

 

[chuck]

Hello Gordon,

The 20th edition of the ARRL Antenna Handbook has some
information on a 40 meter, masthead half-sloper as you
described. You might find that interesting.

As Doug mentioned, this is basically a single-band antenna,
except that it would probably work ok on odd harmonic
frequencies. And it would very definitely radiate on other
frequencies in an emergency, provided you used an
appropriate tuner.

Good luck!

Chuck

 

[Gordon Wedman]

Hi Chuck
I kind of suspected that it would only work well over a limited frequency
range and that the typical antenna tuners would not help. Thanks to Doug
and yourself for confirming this. I'm not planning on installing one as I
have a conventional backstay arrangement but I was just wondering if anyone
actually used this kind of setup as I'd not seen it discussed.
I guess if you are a Ham and tend to work only one band this might be a good
arrangement for your boat.

 

[Doug Dotson]

Actually, as a ham I tend to work many bands. Probably more thatn a typical
marine SSB operator might. So, a single band antenna on a boat is probably
too limiting in many cases.

Doug, k3qt
s/v CAllista

 

[Terry Spragg]

Hi Chuck
I kind of suspected that it would only work well over a limited frequency
range and that the typical antenna tuners would not help. Thanks to Doug
and yourself for confirming this. I'm not planning on installing one as I
have a conventional backstay arrangement but I was just wondering if anyone
actually used this kind of setup as I'd not seen it discussed.
I guess if you are a Ham and tend to work only one band this might be a good
arrangement for your boat.

I think it's a great idea. If you tune to some "off" freqs, you
could try orienting the AE different ways by turning the boat. You
may be surprised to find directivity nodes here and there at certain
freqs.

I have often wondered why I don't get a ham set, or even a decent
receiver, so I can fool around with some weird AE Ideas. How about a
loop using the fore and back stays, insulated at the top, a balanced
twinax feed and connected from fore peak to transom by an insulated
bilge wire on spacers away from the bottom of the hull?

Alternatively, my mind says "Why not feed at the centre of the
bilge lead, or even off centre, and maybe not bother insulating the
stays at the top?" The shrouds would not be connected to anything
at the chain plates.

I suspect directivity trials could yield a neat plot showing odd
peaks and strange directivity. Some of those nodes may be surprising
and even useful.

Loops are particularly quiet on Rx. Ever try one for Tx?

Has anybody actually done any of this wierd stuff?

It seems to me that some software should be able to predict all
this. Anybody know?

Terry K

 

[Jack Painter]

Has anybody actually done any of this wierd stuff?

It seems to me that some software should be able to predict all
this. Anybody know?

Terry K

http://www.eznec.com/ There is a free demo-version available here.

Jack Painter
Virginia Beach, Virginia

 

[Jack Painter]

IF I were at sea (and I am a ham) I'd still want more than one band
capability, especially were I at sea on a boat. One of the distinct
advantages of ham radio over most services is its ability to choose
the right band for prevailing radio conditions and the path one wants
to work. Being that the ability to summon assistance when needed on
freqs such as 2182 is limited these days I'd want multiband capability
for my hf marine gear when away from land.

Richard Webb, amateur radio callsign nf5b
active on the Maritime Mobile service network, 14.300 mhz

Hi Richard, bravo for your volunteer work for the MMSN. As far as bandwidth
for prevailing conditions, there are quite sufficient bandwidths available
in the Maritime Mobile Service. Below is a little paraphrased version of the
new guard frequencies. Duplex is now history for all hailing and distress
work with the USCG.

Effective January 1, 2005 new guarded calling and distress freq-
uencies for the USCG long range communication stations will now be
Simplex (single channel call and receive). These "new" guard freq-
uencies have always been the voice-associated distress for follow
up to DSC/GMDSS alert system. Now, instead of waiting for a DSC
alert to start listening to the associated voice channel for a
particular DSC frequency, the following associated voice frequencies
will be guarded. Appropriate day/night monitoring will still apply
to the 'new' guard frequencies.

2182 24 HRS Guarded only by USCG Groups

NMN NMF NMG NMC NOJ
4125 2300-1100Z 2300-1100Z 24 HRS
6215 24 HRS 24 HRS 24 HRS
8291 24 HRS 24 HRS
12290 1100-2300Z 24 HRS

16420 is available by request, and in response to 16meg DSC

Effective Jan 01, 2005, the formerly guarded channels (below)
will be used for working frequencies only after initial contact
is made via simplex on the the guarded channels above.

ITU SHIP SHORE Sched (UTC)
NMN NMN/NMF/NMG
424 4134 4426 n/a n/a n/a n/a
601 6200 6501 n/a n/a n/a n/a
816 8240 8764 n/a n/a n/a n/a
1205 12242 13089 n/a n/a n/a n/a
1625 16432 17314 n/a n/a n/a n/a

See http://www.navcen.uscg.gov/marcomms/cgcomms/call.htm for
details concerning long range HF communications with USCG units.

Jack Painter
"Oceana Radio" USCGAUX
Virginia Beach, Virginia

 

[Doug Dotson]

IF I were at sea (and I am a ham) I'd still want more than one band
capability, especially were I at sea on a boat. One of the distinct
advantages of ham radio over most services is its ability to choose
the right band for prevailing radio conditions and the path one wants
to work.

The ability to choose bands depending upon conditions is not
distinct to ham radio. Marine SSB supports quite a few different bands
for the exact same reason. Bands are in the 2, 4, 6, 8, 12, 16, 18,
22, and 28 Mhz regions. All modern Marine SSB rigs support all of these.

Being that the ability to summon assistance when needed on
freqs such as 2182 is limited these days I'd want multiband capability
for my hf marine gear when away from land.

2182 isn't considered a good emergency frequency these days and
isn't relied upon. EPIRBs have pretty much made it obsolete. Matter
of fact, the CG doesn't even reliably monitor it.

Richard Webb, amateur radio callsign nf5b
active on the Maritime Mobile service network, 14.300 mhz
REplace anything before the @ symbol with elspider for real email

I check into the MMSN on a regular basis. Maybe I'll hear you
there.

Doug, k3qt
s/v Callista

 

[Doug Dotson]

. As far as bandwidth
for prevailing conditions, there are quite sufficient bandwidths available
in the Maritime Mobile Service. Below is a little paraphrased version of
the
new guard frequencies. Duplex is now history for all hailing and distress
work with the USCG.

What does bandwidth have to do with this. The bandwidth of an SSB
signal is the same regardless of the frequency/band used.

Doug, k3qt
s/v CAllista

 

[Jack Painter]

What does bandwidth have to do with this. The bandwidth of an SSB
signal is the same regardless of the frequency/band used.

Doug, k3qt
s/v CAllista

Doug,

It was a little Freudian slip, sorry. I was describing the more than
sufficient "bands" that are available, and the context of the message surely
was clear to that. I note that you nonetheless repeated pretty much the same
information of my message in your answer. I'm sure glad you cleared that up
before everyone thought bandwidth meant bands! <G>

As to the comments you actually added, such as 2182 khz not being reliable
or used any longer, 2182 khz is most certainly used as a distress and
hailing frequency to raise the USCG, where it is monitored from every USCG
Group, even in places like the Mississippi River where it has completely
fallen out of use due to cell phones, which are never out of coverage in
that area. Using equipment with considerably longer range capabilities than
USCG Groups have at their disposal, I have never heard a call go unanswered
in over six months of dedicated guard on that frequency. Many MAYDAY calls
were answered by several USCG Groups at once. While I would hope we can
continue to improve the quality of equipment available for this work, it is
in no means incapable of doing the job that is expected of it. It is not
likely, in my opinion, that satellite phone links or vessel and personal
EPIRB's will ever completely replace HF emergency communications. If these
newer and more capable equipments do render the average yachtsman or mariner
less familiar with his HF equipment and capabilities (due to infrequent
usage) then that is an issue that can be addressed in boating safety and
professional standards courses. It would be too bad to see such capable
means of communication lost to just an aging part of the hobby field, do you
agree?

Jack Painter
Virginia Beach, Virginia

 

[Doug Dotson]

Doug,

It was a little Freudian slip, sorry. I was describing the more than
sufficient "bands" that are available, and the context of the message
surely
was clear to that. I note that you nonetheless repeated pretty much the
same
information of my message in your answer. I'm sure glad you cleared that
up
before everyone thought bandwidth meant bands! <G>

In all fairness, I looked up "bandwidth: at www.dictionary.com. To my
surprise, the first definition was what you seemed to be saying. That is,
the difference between the upper and lower freqs of the band. I have
never heard this defintion. The only definition I have even know is that
stated in references like the Handbook.

As to the comments you actually added, such as 2182 khz not being reliable
or used any longer, 2182 khz is most certainly used as a distress and
hailing frequency to raise the USCG, where it is monitored from every USCG
Group, even in places like the Mississippi River where it has completely
fallen out of use due to cell phones, which are never out of coverage in
that area. Using equipment with considerably longer range capabilities
than
USCG Groups have at their disposal, I have never heard a call go
unanswered
in over six months of dedicated guard on that frequency. Many MAYDAY calls
were answered by several USCG Groups at once. While I would hope we can
continue to improve the quality of equipment available for this work, it
is
in no means incapable of doing the job that is expected of it. It is not
likely, in my opinion, that satellite phone links or vessel and personal
EPIRB's will ever completely replace HF emergency communications. If these
newer and more capable equipments do render the average yachtsman or
mariner
less familiar with his HF equipment and capabilities (due to infrequent
usage) then that is an issue that can be addressed in boating safety and
professional standards courses. It would be too bad to see such capable
means of communication lost to just an aging part of the hobby field, do
you
agree?

The means of communications is not the issue.

All I can say is that in the only situation where I have ever had to resort
to
calling for help, there was no answer on 2182. I was eventually able to
acheive very poor contact with CG on VHF. I asked if there was an HF freq
that I could contact them on for more reliable comms. The answer was
NO. They could not help me via HF. I was about to try to contact a ham
to relay a message to CG when another boat closer to shore was able
to provide a relay. I would have contacted MMSN but it was 4am and
the net was not on the air. In short, the CG was not there only time I felt
I needed help. I will NEVER, EVER rely on the CG via Marine SSB as a
reliable means of assistance. I can contact a ham anywhere, anytime and
help is then just a phone call away. If that doesn't work (which is
doubtful)
then the EPIRB is the solution.

 

[Jack Painter]

All I can say is that in the only situation where I have ever had to resort
to
calling for help, there was no answer on 2182. I was eventually able to
acheive very poor contact with CG on VHF. I asked if there was an HF freq
that I could contact them on for more reliable comms. The answer was
NO. They could not help me via HF. I was about to try to contact a ham
to relay a message to CG when another boat closer to shore was able
to provide a relay. I would have contacted MMSN but it was 4am and
the net was not on the air. In short, the CG was not there only time I felt
I needed help. I will NEVER, EVER rely on the CG via Marine SSB as a
reliable means of assistance. I can contact a ham anywhere, anytime and
help is then just a phone call away. If that doesn't work (which is
doubtful)
then the EPIRB is the solution.

Well Doug, much as a Mr. James Herbert had to reply concerning the
definition of radio-horizon earlier, I'm sorry I did not consider your
anecdotal evidence about one single bad experience, in which case we could
neither affirm nor indict the equipment performance of your transmitter nor
any receiving station at that single point in time. You have chosen to not
consider the evidence and opinion that I expressed concerning performance of
nineteen USCG Groups, ten Canadian Coast Guard Radio Stations, and Bermuda
Radio, which I studied specifically for such reasons. This research covered
an area from the Canadian Maritimes to Puerto Rico and back inside the Gulf
of Mexico. This would equate to roughly two-thirds of the maritime AOR of
the coastal-continental United States and her neighbors, and for a period of
six months (summer to winter).

I am an accountant and federal contract auditor by profession, and this
study will include sampling and review of complaints of missed calls and
other communications issues. Your experience was first noted by the way,
when we had this discussion some time ago. As I recall, this one event was
too long ago to be considered relevant for current study, as aggravating and
potentially dangerous as I'm sure it was to you.

In the interest of safe boating, I encourage anyone who is contemplating
coastal cruising to contact their local USCG Group well in advance of the
trip, and ask them for the estimated area of VHF and 2182 khz coverage along
the route that they plan to take. An EPIRB is an important safety device in
any cruising vessels inventory, but it cannot replace vital voice
communications.

Best regards,

Jack Painter
Virginia Beach, VA

 

[Doug Dotson]

You know Jack, you could just end this discussion by saying that perhaps
the CG operator at the time was wrong. If the CG now provides
reliable monitoring then that is great for the next time I feel I need
them. More below.

Well Doug, much as a Mr. James Herbert had to reply concerning the
definition of radio-horizon earlier, I'm sorry I did not consider your
anecdotal evidence about one single bad experience, in which case we could
neither affirm nor indict the equipment performance of your transmitter
nor
any receiving station at that single point in time.

You are not listening. The CG told me that there was no way I could
contact them on SSB. I never got the chance to use either my transmitting
equipment or test their receiving equipment.

You have chosen to not
consider the evidence and opinion that I expressed concerning performance
of
nineteen USCG Groups, ten Canadian Coast Guard Radio Stations, and Bermuda
Radio, which I studied specifically for such reasons. This research
covered
an area from the Canadian Maritimes to Puerto Rico and back inside the
Gulf
of Mexico. This would equate to roughly two-thirds of the maritime AOR of
the coastal-continental United States and her neighbors, and for a period
of
six months (summer to winter).

I say again. THE CG TOLD ME I COULD NOT CONTACT THEM
ON SSB! THEY DID NOT SUPPORT SUCH COMMS! It had nothing
to do with equipment, propagation, or any other technical capability. It
had to do with their pollicy as it was announced to me.

I am an accountant and federal contract auditor by profession, and this
study will include sampling and review of complaints of missed calls and
other communications issues. Your experience was first noted by the way,
when we had this discussion some time ago. As I recall, this one event was
too long ago to be considered relevant for current study, as aggravating
and
potentially dangerous as I'm sure it was to you.

It was just under 2 years ago.

In the interest of safe boating, I encourage anyone who is contemplating
coastal cruising to contact their local USCG Group well in advance of the
trip, and ask them for the estimated area of VHF and 2182 khz coverage
along
the route that they plan to take. An EPIRB is an important safety device
in
any cruising vessels inventory, but it cannot replace vital voice
communications.
Agreed.

Best regards,

Jack Painter
Virginia Beach, VA

Doug
s/v CAllista

 

[Doug Dotson]

WAs aware of all of those, but I've heard plenty of horror stories, in
fact some of those horror stories' participants come up on mmsn sans
ham licenses to get help.

There are always plenty of hams listening at any time of day. Much
more reliable than trying to contact the CG.

so I've heard fro m folks in the know, and this includes folks whose
business it is to work with vessels at sea.
I've herad the stories about the radios sitting with the volume
control clear down on 2182 etc. And the mishaps with gmdss. wEre I
cruising I wouldn't put all my eggs in the maritime ssb basket since I
have a ham license. THe life I save might be my own <g>.

Smart move!

I'm net control operator Fridays at 12:00 P.M. eastern time and do
some relief for other operators when I'm available.

I'll try to get down to the boat and check in then.

Btw even after hours if you can be heard in NEw Orleans La on 14
megahertz about any hour day or night my rig sits monitoring 14.3 if
I'm not on another net somewhere. I think same is true of other net
regulars. IF you're in need give it a try. IF the band's open you'll
be ehard by someone who is aware of what to do to render assistance to
you.

If I can hear kd4bz in Eight Mile, AL with a 59 then I should have
no trouble getting into New Orleans.

 

[chuck]

Hello Jack,

There do seem to be a variety of perceptions of USCG
monitoring activities on 2182 and elsewhere. Perhaps you
could direct us to a website or online document that details
distress calls received by the CG on various frequencies.

Of course, calls never intercepted are not likely to be
reported in such a study since the unsuccessful caller kind
of self-destructs. I do believe all boaters would benefit
from objective data on the issue.

Many thanks!

Chuck

 

[Jack Painter]

"Doug Dotson" wrote

more reliable than trying to contact the CG.

=================================================
This is the worst advise I have ever heard from an otherwise knowledgeable
person.
It is inaccurate, dangerous, and reflects only the personal opinion of a Ham
operator who is spreading misinformation about the USCG, safe boating
procedures and the priority of emergency communications at sea. Mariners
should understand and follow only approved USCG procedures for emergency
communications at sea. The great work of the Maritime Mobile Service Network
in assisting mariners via long range HF communications is NEVER to be given
priority over contact with USCG units for safety of life at sea. MMSN is a
wonderful tool for boaters who are also licensed Ham operators, and its many
operators would help ANY vessel they are able to assist. But MMSN should
only be used in an emergency as an ALTERNATE to primary USCG communications
for safety of life at sea.

See http://www.navcen.uscg.gov/marcomms/cgcomms/call.htm for detailed
information.

Drill up from that URL to find details of other maritime communications
information.

Jack Painter
Virginia Beach, VA
=================================================
Chuck that should also answer your question from this thread.