Re: [digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?

[Rick W]

Skip,

Have you found that DominoEX is the best overall digital mode for FM? I 
know that PSK modes can have doppler errors from aircraft, but otherwise 
seem pretty good for weak signal.

Your point is well taken that many of the hams who participate in public 
service activities, may tend to be the younger ones who are Technician 
class and can mostly operate on 6 meters and up with their vertical 
antennas and FM only rigs. The number of hams with the 
multimode/multiband rigs is increasing, at least in our area. It is not 
easy to get them to try SSB, much less SSB digital though.

The claim about the ground gain for horizontal antennas may be true but 
I have not seen this definitely tested. Have you done some comparisons 
with low 2 meter antennas, such a mobile to low base antenna with V and 
H and found H consistently better? I don't hold too much stock in 
software modeling and only would go with empirical data for that kind of 
test.

We will probably bite the bullet eventually and put a rotor back up on 
the low tower and maybe go with a Gulf Alpha 11 element V and H antenna 
for some reasonable gain. Then we could do the test. The ham that was 
going to help us lost his QTH and will not be able to relocate his VHF 
antenna farm. Of course they are quite high so maybe there would not 
have been as much difference in such a case. One of the best known VHF 
ops in my Section says that after running many tests he has never found 
either polarization is any different. But he has high antennas so maybe 
that accounts for it.

We hope at least soon do some digital mode comparisons on 2 meters, 
whether SSB or FM.

73,

Rick, KV9U




kh6ty wrote:
> Hi Rick,
>
> Thank you for your comments on Howard's and my posts.
>
> Of course, we prefer using SSB on VHF, because the range is longer. First 
> tests indicate that DominoEX with SSB has at least a 3 dB advantage over 
> using FM with DominoEx. We are arranging more tests to be sure.
>
> However,  the fact that today, maybe half of the U.S. amateurs hold only a 
> Technician license, and do not have access to full HF priviledges, together 
> with the fact that many hams only have inexpensive FM-only transceivers (but 
> only a relative few may have VHF or multimode 2m transceivers with SSB 
> capability), we have decide to explore ways that more hams can participate 
> in emcomm activities, which means finding out how to use FM-only 
> transceivers without repeater assistance.
>
> Although you have previously pointed out that many hams already have 
> vertical antennas, the fact remains that a vertical antenna close to the 
> ground (2 wavelengths), has about 6 dB less gain than the same antenna 
> horizontally polarized. At VHF, a 6 dB disadvantage is an enormous 
> disadvantage, plus many of the directive antennas used for FM are fixed on a 
> particular repeater, and cannot currently be rotated anyway. Just model a 
> vertically-polarized antenna over real ground at 2 wavelengths and compare 
> the gain to the same antenna rotated 90 degrees to horizontal polarization 
> to see the difference. In order to confirm Cebik's assertion about the gain 
> difference, I did the modeling myself and found that he is absolutely 
> correct. No difference in free space, but a huge difference over real 
> ground.
>
> So, putting it all together, we can get significantly more range by simply 
> investing in a horizontally-polarized antenna, using the same FM transceiver 
> that people already have, and, better yet, in an inexpensive TV antenna 
> rotator so we can communicate in any direction. The optimized two-element 
> quad that we used for the FM/DominoEx tests (7.5 dBi in free space) can be 
> built for less than $15 in an hour with all parts from Lowes, plus a SO-239 
> connector, and turned with a $60 Philips TV antenna rotator from Walmart, 
> because its wind loading and boom length (13") is so small. A picture of the 
> little quad is here: http://home.comcast.net/~hteller/OptimizedQuad.jpg. It 
> is only 20" x 20" x 13", so it will fit in the trunk of a car without having 
> to be dismanteled. Construction uses schedule 40 PVC, fiberglass "driveway 
> markers" for spreaders, and #14 insulated house wire, so it is very rugged.
>
> I wish that all existing equipment could be used intead, but without a gain 
> antenna and horizontal polarization, range without repeater assistance 
> appears to be just too limited.
>
> It would be useful to know how much range you can get in your hilly rural 
> area by using FM, DominoEx, and horizontal antennas on 2m.
>
> 73, Skip KH6TY
> NBEMS Development Team
>
>   

RE: [digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?

[Fred VE3FAL]

“In this county you can sum up the biggest problem in 
one word "manpower". Within my zip code there is 
3 hams living in town.

One is up in the years and has not been on the air in 
years as well as to weak to do much.

As far as the other 2, one is chief of police. The other
is #2 in command on the fire department.”

 

 

I passed the question to my ARES crew that is posted in the subject area as
it is an important question and with great scenarios.

We just went through the largest mass exercise in Ontario called Trillium
Exercise here in Thunder Bay Ontario. ARES was not involved as much as they
should have been but we did have a chance to pass traffic via radio during
the time.

Anyhow, we too are in an area where we have a large mass of land and few
hams to fill it. I have many areas in my ARES district that are vacant, so
again getting those messages there are going to be tough both ways if all
power and communications are down.

 

Consensus here has MT63 as the mode of choice in digital traffic and use of
NVIS antennas.

We use it for CFARS as well…

 

Anyway, I think it is a great question and some good answers have come out
of it.

 

Regards

Fred

VE3FAL

 

-Original Message-
From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On
Behalf Of Charles Brabham
Sent: Wednesday, November 26, 2008 6:22 PM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Re: How Can We Push HF Emcomm Messages to the
Field?

 

One obvious choice for pushing messages to the field would be multicast ( on
any band, depending on the range you are after, etc.. )

 

One transmitter pushes the data to an unlimited number of recipients, who
all get it at the same time. No point-to-point system can compete with it,
multicast is much, much faster for distributing the same data to many
locations.

 

Learn about multicast at these plasces:

 

http://uspacket.org/smf/index.php?board=6.0;sort=subject

 

http://uspacket.org/smf/index.php?topic=9

 

The second link is only for the truly curious - the article is long-winded!

 

Pardon my typing, my vision is not good today and I'm a hunt 'n peck typist.

 

73 DE Charles Brabham, N5PVL

 

 

 

 

- Original Message - 

From: John Becker,   WØJAB 

To: digitalradio@yahoogroups.com 

Sent: Wednesday, November 26, 2008 4:41 PM

Subject: Re: [digitalradio] Re: How Can We Push HF Emcomm Messages to the
Field?

 

In this county you can sum up the biggest problem in 
one word "manpower". Within my zip code there is 
3 hams living in town.

One is up in the years and has not been on the air in 
years as well as to weak to do much.

As far as the other 2, one is chief of police. The other
is #2 in command on the fire department.

 

[digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?

[Howard Z.]

Yes indeed - I have found that nothing on HF is reliable 24/7.

One can not reliably reach another country at will regardless of 
equipment.

Local NVIS operation also has problems.
In my MARS group before DST ended, conditions were pretty bad 
because we started before sunrise - and then everything was find 
after sunrise.  Sometimes we change frequencies which can help, but 
few members have antennas for 2 Mhz, so there are limits to that 
approach.

I used to use an inverted dipole 10 to 20 ft above ground.  I found 
one member who always sounded great and could always hear me no 
matter what.  Turns out he uses a one wavelength loop, and that is 
what I use now.  I think just about everyone hears me fine - I get 
good reports, but I don't hear everyone well under those occassional 
bad conditions.  I am using a 1:1 balun, and I read that a balun is 
unnecessary with a one wavelength loop antenna, so I'm going to try 
eliminating the balun next month to see if it makes a difference.

MARS uses NVIS SSB HF from 2 Mhz to 30 Mhz as the primary emcomm 
mode. Voice, digital, and winlink.

I do admit it does not work 24/7, but nothing on HF does.
Since morse code is eliminated, it is relatively easy for people to 
upgrade to General licenses - but it does take some effort.

If VHF can get the job done for your circumstances - it's cheaper, 
antennas are smaller, mobile use is easy, etc etc.

Howard

[digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?

[Howard Z.]

I deleted the posting a few minutes after I made it.

I realized it was inappropriate.

I somehow felt I was being challenged to a debate,

All I did was give someone my 2 cents,
and dozens of others would also likely give their opinions.

I don't know why, but I reacted badly to the post directed to me.
I thought the identity of the original person with the problem who 
posted the question had been lost and I had been nominated in his 
place.

But, I re-read my posting, and considered it inappropriate,
and I deleted it hoping nobody would read it.

Howard

--- In digitalradio@yahoogroups.com, "kh6ty" <[EMAIL PROTECTED]> wrote:
>
> Howard,
> 
> First of all, there is no need to shout! My old eyes are still 
fine for 
> reading without your using caps! :-)
> 

Re: [digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?

[kh6ty]

No hard feelings, Howard!

Your passion for the hobby is appreciated, and many of us have hit the Send 
key,  wishing immediately afterward that we had not!

Regardless, I thought many of your points were well made and bared 
repeating.

73, Skip KH6TY
NBEMS Development Team


- Original Message - 
From: "Howard Z." <[EMAIL PROTECTED]>
To: 
Sent: Wednesday, November 26, 2008 6:32 PM
Subject: [digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?


I deleted that posting soon after I made it.
However, I suppose those who get emails still got it.

My posting was not appropriate.
I appologize.

Howard





Internal Virus Database is out of date.
Checked by AVG - http://www.avg.com
Version: 8.0.138 / Virus Database: 270.9.2/1785 - Release Date: 11/13/2008 
9:12 AM

[digitalradio] Skip - Quad detials?

[Rud Merriam]

Could you provide sufficient details on the quad to allow building it?  

 
Rud Merriam K5RUD 
ARES AEC Montgomery County, TX
http://TheHamNetwork.net

[digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?

[Howard Z.]

I deleted that posting soon after I made it.
However, I suppose those who get emails still got it.

My posting was not appropriate.
I appologize.

Howard

Re: [digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?

[Charles Brabham]

One obvious choice for pushing messages to the field would be multicast ( on 
any band, depending on the range you are after, etc.. )

One transmitter pushes the data to an unlimited number of recipients, who all 
get it at the same time. No point-to-point system can compete with it, 
multicast is much, much faster for distributing the same data to many locations.

Learn about multicast at these plasces:

http://uspacket.org/smf/index.php?board=6.0;sort=subject

http://uspacket.org/smf/index.php?topic=9

The second link is only for the truly curious - the article is long-winded!

Pardon my typing, my vision is not good today and I'm a hunt 'n peck typist.

73 DE Charles Brabham, N5PVL




  - Original Message - 
  From: John Becker, WØJAB 
  To: digitalradio@yahoogroups.com 
  Sent: Wednesday, November 26, 2008 4:41 PM
  Subject: Re: [digitalradio] Re: How Can We Push HF Emcomm Messages to the 
Field?


  In this county you can sum up the biggest problem in 
  one word "manpower". Within my zip code there is 
  3 hams living in town.

  One is up in the years and has not been on the air in 
  years as well as to weak to do much.

  As far as the other 2, one is chief of police. The other
  is #2 in command on the fire department.



   

Re: [digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?

[John Becker, WØJAB]

In this county you can sum up the biggest problem in 
one word  "manpower". Within my zip code there is 
3 hams living in town.

One is up in the years and has not been on the air in 
years as well as to weak to do much.

As far as the other 2, one is chief of police. The other
is #2 in command on the fire department.

[digitalradio] Correction on URL for Optimized Quad

[kh6ty]

The correct URL for the picture of the two-element Optimized Quad is 
http://home.comcast.net/~hteller/OptimizedQuad.jpg

A period at the end of the link in my email accidentally got included in the 
URL.

Skip KH6TY


- Original Message - 
From: "Howard Z." <[EMAIL PROTECTED]>
To: 
Sent: Wednesday, November 26, 2008 1:42 PM
Subject: [digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?


SKIP SKIP SKIP
READ READ READ

I, HOWARD, AM not not NOT NOT not THE PERSON WITH THE QUESTION NOR
THE PROBLEM.

GEEZ, I TRY TO ANSWER SOMEONE'S QUESTION, AND SUDDENLY IT BECOMES MY
QUESTION AND MY PROBLEM.

If you are going to address someone - address the individual who has
the problem or question in the first place.

Personally - I don't care.
Personally, I am an emergency worker who will never ever be sent to
help in an ARES/RACES HAM group, because my agency will need me here.
If it snows 20 feet one day, I'll be disciplined if I do not get to
work - lose all bonuses and raises for a year.
Personally, I already own expensive HF equipment and consider VHF
short range no matter what you do with it - compared to a few
hundred miles one gets via HF with a NVIS antenna 10 feet above
ground.  Personally, I think VHF is nice for 10 to 20 miles - you
can go further - nice for you.  I'll keep it in mind if anyone gets
a team of bulldozers and makes Maryland flat - I can't walk a block
or two with reaching a hill.

I am not the one who asked the question.
I am not the one who asked the question.
Don't try giving me advise when I am not the one who asked the
question.

The original poster who posed the question and who has the problem
was considering HF as a solution.

Watson, I think he's got it... maybe.


Howard

--- In digitalradio@yahoogroups.com, "kh6ty" <[EMAIL PROTECTED]> wrote:
>
> Howard,
>
> We already achieved successful, error-free, VHF communication
(with no
> repeated blocks) using NBEMS software over a 70 mile path in flat
country
> between two 50 watt FM transceivers, one with a 7.5 dBi antenna at
10 feet
> off the ground and the other with a 7.5 dBi antenna 25 feet off
the ground.
> I have also developed a DOX interface for FM transceivers which
have no VOX.
> A schematic is here:
> http://home.comcast.net/~hteller/Interface%20schematic.jpg
>
> We are now in the process of determining just how much farther we
can go
> using FM. However, using SSB with DominoEX, we have already
reached 100
> miles consistently between a 9 dBi antenna and a 13 dBi antenna.
We think
> that a 100 mile capability is sufficient to reach outside
connectivity for
> email or phone delivery and confirmation. If so, then VHF can be
used most
> of the time. By using 2m, if the S/N is sufficient, we can also
use phone
> and data  interchangably on the same frequency, which is not
permitted on
> HF.
>
> When the terrain is too hilly for VHF, NBEMS also supports Hf
using NVIS
> antennas with several modes specifically tailored to work under
very high
> static conditions.
>
> However, it obviously easier to put up a small beam than it is to
always
> find supports for a NVIS antenna for portable use. A picture of my
2m
> portable setup is here:
http://home.comcast.net/~hteller/sideview.jpg. By
> using a two section mast, everything will fit in the trunk or in
the back
> seat.
>
> NBEMS does not support "push" emcomm email, because there is no
confirmation
> of delivery. Instead, there must just be an operator present at
each end of
> the link. This also helps prevent transmitting on an already
active
> frequency.
>
> As you correctly note, VHF FM transceivers cost only a couple of
hundred
> dollars instead of a thousand for SSB-capable transceivers,
however, it is
> absolutely necessary to use horizontally-polarized, gain, antennas
to go
> farther than a repeater can go. The portable station antenna is
usually
> going to be near the ground, and at 10 feet off the ground, there
is a huge
> 6 dB penalty to using vertical polarization. We are now changing
the
> emphasis of NBEMS from SSB to FM with DominoEX in order to make it
possible
> for more people to use NBEMS and also take advantage of the low
cost FM-only
> transceivers in the field.
>
> There appears to be a 3 dB or greater disadvantage to using FM
over SSB,
> even with horizontally-polarized antennas, but that can be made up
with
> increased antenna gain or power. Phone will not work on VHF over
the same
> long distances as DominoEX or MFSK16 will work, because the noise
level is
> often so high, the voice just cannot be understood or even heard
at all.
> However, DominoEX and MFSK16 can still decode when the S/N is 10
or 12 dB
> UNDER the noise level, and that is how we get such long distance
> communication on 2m.
>
> 73, Skip KH6TY
> NBEMS Development Team
>
> - Original Message - 
> From: "Howard Z." <[EMAIL PROTECTED]>
> To: 
> Sent: Tuesday, November 25, 2008 6:58 PM
> Subject: [digitalradio] Re: How Can We Push HF Emcomm Messages to
the Field?
>
>
> I

Re: [digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?

[kh6ty]

Hi Rick,

Thank you for your comments on Howard's and my posts.

Of course, we prefer using SSB on VHF, because the range is longer. First 
tests indicate that DominoEX with SSB has at least a 3 dB advantage over 
using FM with DominoEx. We are arranging more tests to be sure.

However,  the fact that today, maybe half of the U.S. amateurs hold only a 
Technician license, and do not have access to full HF priviledges, together 
with the fact that many hams only have inexpensive FM-only transceivers (but 
only a relative few may have VHF or multimode 2m transceivers with SSB 
capability), we have decide to explore ways that more hams can participate 
in emcomm activities, which means finding out how to use FM-only 
transceivers without repeater assistance.

Although you have previously pointed out that many hams already have 
vertical antennas, the fact remains that a vertical antenna close to the 
ground (2 wavelengths), has about 6 dB less gain than the same antenna 
horizontally polarized. At VHF, a 6 dB disadvantage is an enormous 
disadvantage, plus many of the directive antennas used for FM are fixed on a 
particular repeater, and cannot currently be rotated anyway. Just model a 
vertically-polarized antenna over real ground at 2 wavelengths and compare 
the gain to the same antenna rotated 90 degrees to horizontal polarization 
to see the difference. In order to confirm Cebik's assertion about the gain 
difference, I did the modeling myself and found that he is absolutely 
correct. No difference in free space, but a huge difference over real 
ground.

So, putting it all together, we can get significantly more range by simply 
investing in a horizontally-polarized antenna, using the same FM transceiver 
that people already have, and, better yet, in an inexpensive TV antenna 
rotator so we can communicate in any direction. The optimized two-element 
quad that we used for the FM/DominoEx tests (7.5 dBi in free space) can be 
built for less than $15 in an hour with all parts from Lowes, plus a SO-239 
connector, and turned with a $60 Philips TV antenna rotator from Walmart, 
because its wind loading and boom length (13") is so small. A picture of the 
little quad is here: http://home.comcast.net/~hteller/OptimizedQuad.jpg. It 
is only 20" x 20" x 13", so it will fit in the trunk of a car without having 
to be dismanteled. Construction uses schedule 40 PVC, fiberglass "driveway 
markers" for spreaders, and #14 insulated house wire, so it is very rugged.

I wish that all existing equipment could be used intead, but without a gain 
antenna and horizontal polarization, range without repeater assistance 
appears to be just too limited.

It would be useful to know how much range you can get in your hilly rural 
area by using FM, DominoEx, and horizontal antennas on 2m.

73, Skip KH6TY
NBEMS Development Team

- Original Message - 
From: "Rick W" <[EMAIL PROTECTED]>
To: 
Sent: Wednesday, November 26, 2008 3:38 PM
Subject: Re: [digitalradio] Re: How Can We Push HF Emcomm Messages to the 
Field?


> Hi Howard,
>
> If you respond to someone's response to a question, with asking
> questions of your own, then it might be reasonable for some to respond
> as Skip did. It seems reasonable to me considering you asked "Is the
> volunteer out of VHF range?" You also asked about setting up something
> in the bed of a truck and asked about setting up something on HF after
> arrival at the destination. All good questions.
>
> While your particular job situation does not seem relevant to this
> discussion, the use of VHF, especially SSB VHF does seem particularly
> relevant since it is the only other way to get increased distance of
> communication between a mobile and fixed/portable/mobile station if HF
> is not workable.
>
> The most expensive HF equipment may of of no value when you are trying
> to communicate between two points that do not have NVIS propagation. It
> can be frustrating, especially during high QRN as well as the skywave
> signal just going through the ionosphere and not reflecting back down.
> For those experienced with Section level nets that only use 75/80
> meters, you know what I mean.
>
> Going higher in HF frequency doesn't work any better (actually shorter
> ground/direct wave), and that is why STANAG systems won't work for
> "local" communication.
>
> VHF simplex with FM and with minimal antennas are not going to go all
> that far as you point out. In fact, in our area, it is difficult enough
> for mobiles to repeaters. Sometimes 15 to 20 miles is the best you can
> do in shaded areas. With 2 meter SSB, we seem to be able to still get
> through when FM can not get through although signals can be very weak.
> That is using half wave base to quarter wave mobile antennas. With
> improved antennas, depending upon terrain, the distance is going to
> extend out to as much as 50 to 100 miles.
>
> This is important because you reduce QRN problems from lightning static
> and other noise (admittedly l

Re: [digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?

[kh6ty]

Howard,

First of all, there is no need to shout! My old eyes are still fine for 
reading without your using caps! :-)

This group is for the purpose of discussion about using digital modes in 
amateur radio, all opinions are welcome, and nothing should not be held 
against a person for posting a contrary opinion.

>Personally, I already own expensive HF equipment and consider VHF
short range no matter what you do with it - compared to a few
hundred miles one gets via HF with a NVIS antenna 10 feet above
ground.  Personally, I think VHF is nice for 10 to 20 miles - you
can go further - nice for you.  I'll keep it in mind if anyone gets
a team of bulldozers and makes Maryland flat - I can't walk a block
or two with reaching a hill.

Your statement that "VHF is nice for 10-20 miles", is what we find also 
(using phone, and a 5/8 wavelength vertical whip on a car), but I was only 
tryng to point out that if you use horizontal polarization and sensitive 
digital modes, you can go much, much, farther, and we have established that 
over flat country. Vertical polarization with omnidirectional antennas are 
perfect for mobile use, and that is why we have repeaters today, but the 
range is very limited, as you point out. However HF is also often not 
reliable, especially during the time of day that 40m fades out and 80m comes 
up, or later, when 80m fades also, even using NVIS antennas. We have made 
many months of NBEMS tests on HF to realize that. In contrast, when VHF can 
be used, propagation is always consistent up to about 100 miles away. We are 
continually looking for ways to provide the most dependable messaging system 
at any time of day or night, and using VHF is one of those ways.

I also clearly stated, "When the terrain is too hilly for VHF, NBEMS also 
supports Hf using NVIS antennas with several modes specifically tailored to 
work under very high static conditions". However HF is not the only way 
reliable communications can be achieved, at least in non-hilly country.

I was not trying to give you any "advice", or make someone elses "problem" 
yours, but only to address the opinions in your own post. It is not 
necessary to be sarcastic - if my post, opinions, or findings displease you, 
simply use your delete key! ;-)

For everyone else, please take note that it is a significant finding that 
long-range communications using FM and DominoEx can more than triple the 
range of FM phone communications "in flat country", but we still have to 
find out what ranges are possible in hilly country compred to phone 
communications.

Perhaps someone will explain it better, but my guess that when all signals 
encounter an obstacle such as the curvature of the earth (line of sight?), 
they diffract and scatter, losing most of their original strength. However, 
sensitive digital modes can still recover information from the very weak 
scattered waves, and that is why we can still copy with digital modes when 
you cannot even tell that a phone signal is no longer present. Since VHF 
phone signals are limited in general by the encounter with the curvature of 
the earth, it just makes sense to see what can be done with those weak 
scattered waves, and that is what we are trying to find out.

If anything in my previous post is useful to anyone, please feel free to use 
it. Even the digital interface for FM transceivers can be useful, as it can 
be built for $10, which is much less than the $100 SignaLink USB, which also 
has its own DOX.

73, Skip KH6TY
NBEMS Development Team




- Original Message - 
From: "Howard Z." <[EMAIL PROTECTED]>
To: 
Sent: Wednesday, November 26, 2008 1:42 PM
Subject: [digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?


SKIP SKIP SKIP
READ READ READ

I, HOWARD, AM not not NOT NOT not THE PERSON WITH THE QUESTION NOR
THE PROBLEM.

GEEZ, I TRY TO ANSWER SOMEONE'S QUESTION, AND SUDDENLY IT BECOMES MY
QUESTION AND MY PROBLEM.

If you are going to address someone - address the individual who has
the problem or question in the first place.

Personally - I don't care.
Personally, I am an emergency worker who will never ever be sent to
help in an ARES/RACES HAM group, because my agency will need me here.
If it snows 20 feet one day, I'll be disciplined if I do not get to
work - lose all bonuses and raises for a year.
Personally, I already own expensive HF equipment and consider VHF
short range no matter what you do with it - compared to a few
hundred miles one gets via HF with a NVIS antenna 10 feet above
ground.  Personally, I think VHF is nice for 10 to 20 miles - you
can go further - nice for you.  I'll keep it in mind if anyone gets
a team of bulldozers and makes Maryland flat - I can't walk a block
or two with reaching a hill.

I am not the one who asked the question.
I am not the one who asked the question.
Don't try giving me advise when I am not the one who asked the
question.

The original poster who posed the question and who has the problem
was considering HF as

Re: [digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?

[Rick W]

Hi Howard,

If you respond to someone's response to a question, with asking 
questions of your own, then it might be reasonable for some to respond 
as Skip did. It seems reasonable to me considering you asked "Is the 
volunteer out of VHF range?" You also asked about setting up something 
in the bed of a truck and asked about setting up something on HF after 
arrival at the destination. All good questions.

While your particular job situation does not seem relevant to this 
discussion, the use of VHF, especially SSB VHF does seem particularly 
relevant since it is the only other way to get increased distance of 
communication between a mobile and fixed/portable/mobile station if HF 
is not workable.

The most expensive HF equipment may of of no value when you are trying 
to communicate between two points that do not have NVIS propagation. It 
can be frustrating, especially during high QRN as well as the skywave 
signal just going through the ionosphere and not reflecting back down. 
For those experienced with Section level nets that only use 75/80 
meters, you know what I mean.

Going higher in HF frequency doesn't work any better (actually shorter 
ground/direct wave), and that is why STANAG systems won't work for 
"local" communication.

VHF simplex with FM and with minimal antennas are not going to go all 
that far as you point out. In fact, in our area, it is difficult enough 
for mobiles to repeaters. Sometimes 15 to 20 miles is the best you can 
do in shaded areas. With 2 meter SSB, we seem to be able to still get 
through when FM can not get through although signals can be very weak. 
That is using half wave base to quarter wave mobile antennas. With 
improved antennas, depending upon terrain, the distance is going to 
extend out to as much as 50 to 100 miles.

This is important because you reduce QRN problems from lightning static 
and other noise (admittedly less likely though during a time when power 
has failed), and you rarely would need that much distance for Incident 
Command to the dispatched mobile.

Bottom line is that HF may not be able to do it 24/7, but 2 meter SSB 
may be the best choice. With today's relatively low cost 
multimode/multiband rigs, the cost is around $700 or so for 50 watts on 
2 meter SSB. As you point out, these rigs are more expensive than 2 
meter FM, but tremendously more flexible and a very good value since you 
also get an HF rig too.

73,

Rick, KV9U
Moderator, HFDEC yahoogroup

Howard Z. wrote:
> SKIP SKIP SKIP
> READ READ READ
>
> I, HOWARD, AM not not NOT NOT not THE PERSON WITH THE QUESTION NOR 
> THE PROBLEM.
>
> GEEZ, I TRY TO ANSWER SOMEONE'S QUESTION, AND SUDDENLY IT BECOMES MY 
> QUESTION AND MY PROBLEM.
>
> If you are going to address someone - address the individual who has 
> the problem or question in the first place.
>
> Personally - I don't care.
> Personally, I am an emergency worker who will never ever be sent to 
> help in an ARES/RACES HAM group, because my agency will need me here.
> If it snows 20 feet one day, I'll be disciplined if I do not get to 
> work - lose all bonuses and raises for a year.
> Personally, I already own expensive HF equipment and consider VHF 
> short range no matter what you do with it - compared to a few 
> hundred miles one gets via HF with a NVIS antenna 10 feet above 
> ground.  Personally, I think VHF is nice for 10 to 20 miles - you 
> can go further - nice for you.  I'll keep it in mind if anyone gets 
> a team of bulldozers and makes Maryland flat - I can't walk a block 
> or two with reaching a hill.
>
> I am not the one who asked the question.
> I am not the one who asked the question.
> Don't try giving me advise when I am not the one who asked the 
> question.
>
> The original poster who posed the question and who has the problem 
> was considering HF as a solution.
>
> Watson, I think he's got it... maybe.
>
>
> Howard
>  
>   

[digitalradio] Re: RFSM8000 new version

[Howard Z.]

There is another problem with RFSM8000 which I hope the author will
correct.

It seems impossible to start a subject with "//MARS R/" to send an
email message to winlink.org to a MARS account.

MARS winlink accounts do not have functional whitelists, and all
messages must have a subject starting with "//MARS R/" or "//MARS P/".

Howard
N3ZH

[digitalradio] Re: RFSM8000 new version

[Howard Z.]

There is another problem with RFSM8000 which I hope the author will 
correct.

It seems impossible to start a subject with "//MARS R" to send an 
email message to winlink.org to a MARS account.

MARS winlink accounts do not have functional whitelists, and all 
messages must have a subject starting with "//MARS R" or "//MARS P".

Howard
N3ZH

[digitalradio] RFSM8000 new version

[Howard Z.]

There is a relatively new version of RFSM8000 #535

In the email server mode - email would go out on the internet to 
someone's personal or bussiness email without a FROM address.  Thus 
how to reply was difficult or non obvious.

This is now fixed.  The FROM address is now the email address the 
RFSM8000 email server uses.  The person replying still needs to start 
the subject with the call-sign of the RFSM8000 user who originated the 
message.

Howard.

[digitalradio] Re: How Can We Push HF Emcomm Messages to the Field?

[Howard Z.]

SKIP SKIP SKIP
READ READ READ

I, HOWARD, AM not not NOT NOT not THE PERSON WITH THE QUESTION NOR 
THE PROBLEM.

GEEZ, I TRY TO ANSWER SOMEONE'S QUESTION, AND SUDDENLY IT BECOMES MY 
QUESTION AND MY PROBLEM.

If you are going to address someone - address the individual who has 
the problem or question in the first place.

Personally - I don't care.
Personally, I am an emergency worker who will never ever be sent to 
help in an ARES/RACES HAM group, because my agency will need me here.
If it snows 20 feet one day, I'll be disciplined if I do not get to 
work - lose all bonuses and raises for a year.
Personally, I already own expensive HF equipment and consider VHF 
short range no matter what you do with it - compared to a few 
hundred miles one gets via HF with a NVIS antenna 10 feet above 
ground.  Personally, I think VHF is nice for 10 to 20 miles - you 
can go further - nice for you.  I'll keep it in mind if anyone gets 
a team of bulldozers and makes Maryland flat - I can't walk a block 
or two with reaching a hill.

I am not the one who asked the question.
I am not the one who asked the question.
Don't try giving me advise when I am not the one who asked the 
question.

The original poster who posed the question and who has the problem 
was considering HF as a solution.

Watson, I think he's got it... maybe.


Howard
 
--- In digitalradio@yahoogroups.com, "kh6ty" <[EMAIL PROTECTED]> wrote:
>
> Howard,
> 
> We already achieved successful, error-free, VHF communication 
(with no 
> repeated blocks) using NBEMS software over a 70 mile path in flat 
country 
> between two 50 watt FM transceivers, one with a 7.5 dBi antenna at 
10 feet 
> off the ground and the other with a 7.5 dBi antenna 25 feet off 
the ground. 
> I have also developed a DOX interface for FM transceivers which 
have no VOX. 
> A schematic is here: 
> http://home.comcast.net/~hteller/Interface%20schematic.jpg
> 
> We are now in the process of determining just how much farther we 
can go 
> using FM. However, using SSB with DominoEX, we have already 
reached 100 
> miles consistently between a 9 dBi antenna and a 13 dBi antenna. 
We think 
> that a 100 mile capability is sufficient to reach outside 
connectivity for 
> email or phone delivery and confirmation. If so, then VHF can be 
used most 
> of the time. By using 2m, if the S/N is sufficient, we can also 
use phone 
> and data  interchangably on the same frequency, which is not 
permitted on 
> HF.
> 
> When the terrain is too hilly for VHF, NBEMS also supports Hf  
using NVIS 
> antennas with several modes specifically tailored to work under 
very high 
> static conditions.
> 
> However, it obviously easier to put up a small beam than it is to 
always 
> find supports for a NVIS antenna for portable use. A picture of my 
2m 
> portable setup is here: 
http://home.comcast.net/~hteller/sideview.jpg. By 
> using a two section mast, everything will fit in the trunk or in 
the back 
> seat.
> 
> NBEMS does not support "push" emcomm email, because there is no 
confirmation 
> of delivery. Instead, there must just be an operator present at 
each end of 
> the link. This also helps prevent transmitting on an already 
active 
> frequency.
> 
> As you correctly note, VHF FM transceivers cost only a couple of 
hundred 
> dollars instead of a thousand for SSB-capable transceivers, 
however, it is 
> absolutely necessary to use horizontally-polarized, gain, antennas 
to go 
> farther than a repeater can go. The portable station antenna is 
usually 
> going to be near the ground, and at 10 feet off the ground, there 
is a huge 
> 6 dB penalty to using vertical polarization. We are now changing 
the 
> emphasis of NBEMS from SSB to FM with DominoEX in order to make it 
possible 
> for more people to use NBEMS and also take advantage of the low 
cost FM-only 
> transceivers in the field.
> 
> There appears to be a 3 dB or greater disadvantage to using FM 
over SSB, 
> even with horizontally-polarized antennas, but that can be made up 
with 
> increased antenna gain or power. Phone will not work on VHF over 
the same 
> long distances as DominoEX or MFSK16 will work, because the noise 
level is 
> often so high, the voice just cannot be understood or even heard 
at all. 
> However, DominoEX and MFSK16 can still decode when the S/N is 10 
or 12 dB 
> UNDER the noise level, and that is how we get such long distance 
> communication on 2m.
> 
> 73, Skip KH6TY
> NBEMS Development Team
> 
> - Original Message - 
> From: "Howard Z." <[EMAIL PROTECTED]>
> To: 
> Sent: Tuesday, November 25, 2008 6:58 PM
> Subject: [digitalradio] Re: How Can We Push HF Emcomm Messages to 
the Field?
> 
> 
> Is the volunteer out of VHF range?
> 
> If the base station has a 100 watt VHF radio like the 746pro - you
> might be able to still reach the volunteer, but he may not have
> enough power to get back to you.
> 
> Or he may be out of VHF range.
> 
> HF is the way to go - but both ends of the conversation need NVIS
>