10m ground wave expectations
Joey
I'm trying to determine if I could use 10 meters to contact a station
about 75 miles away with about 2500ft elevation of a couple sets of
hills in between with just simple antennas on either end. Perhaps a
10m dipole on one end and some kind of stealthy one on the other. I
assume this would have to be ground wave only given the distance and
current band conditions.
My parents are both techs so we're currrently limited to parts of 10m
as the lowest band and I'd like to have something reliable without
need repeaters for disaster comms. We actually only have a few single
hop VHF/UHF repeaters between us, though quite a few linked ones.
I've also thought of 6m due to smaller antenna requirements, but I'm
pretty sure this is too far...
Thanks!
Richard Clark
>Hi,
>I'm trying to determine if I could use 10 meters to contact a station
>about 75 miles away
Hi Joey,
That's hit number one, distance at this wavelength.
>with about 2500ft elevation of a couple sets of
>hills in between
That's hit number two with the terrain against you.
>with just simple antennas on either end.
That's hit number three, antennas without gain.
>Perhaps a
>10m dipole on one end and some kind of stealthy one on the other.
That's hit number four, every possibility of being cross polarized,
and with at least one antenna masked by building or foliage to qualify
as "stealthy."
>I
>assume this would have to be ground wave only given the distance and
>current band conditions.
You might try NVIS, but what you say, as follows, doesn't give you
many band options.
>My parents are both techs so we're currrently limited to parts of 10m
>as the lowest band
It's time to upgrade. Consult the new rule changes, take a practice
test, and see what happens.
>and I'd like to have something reliable without
>need repeaters for disaster comms.
Then you really need to stop rationalizing about having a "stealth"
antenna. If this was Hurricane Katrina, how long can you call CQ
under water?
>We actually only have a few single
>hop VHF/UHF repeaters between us, though quite a few linked ones.
>I've also thought of 6m due to smaller antenna requirements, but I'm
>pretty sure this is too far...
Try it first before giving up.
73's
Richard Clark, KB7QHC
Joey
profile and the other end doesn't have much yard space and a big
verticle is certainly not going to be sticking up on top. I suppose I
could making something that's just deployable when needed since this
isn't for day to day use... seems upgrading may help....thx...
On Fri, 27 Apr 2007 09:25:17 -0700, Richard Clark <kb7...@comcast.net>
wrote:
Jimmie D
"Joey" <jo...@nowhere.org> wrote in message
news:dd64339h0kluu9d5k...@4ax.com...
75 miles is a bad distance for 10M I have almost no cotacts at that range.
The few occured while doing mountain toping.. Great time to upgrade just get
online and keep taking practice test until you pass.
nm...@wt.net
75 miles is do-able, but stretching it on 10m..
#1, if using simple antennas, good elevated
verticals, or ground planes would be your
only chance. No way you are likely to make
it with horizontal dipoles. And to make 75
miles, the antennas really need to be fairly high.
The hills may be a problem..
Power would help...
If both stations had high ground planes, to talk
75 miles with any reliability, you really would
need an amp, doing 500+ watts on both ends...
There is no NVIS on 10m, unless you get the
fluke chance of backscatter, or aurora..
I've done both on 10m... Backscatter is not that
uncommon, but the aurora is not going to happen
too often. But I've used aurora propogation to work
stations a lot closer than usual.. Sounds like talking
through a window fan... The last time I did that was
in the late 80's at the solar cycle peak.
Anyway, talking 75 miles reliably on 10 can be done,
but most that do it run high verticals, or beams,
and most run power. Note CBers.. They do it all
the time.
But again, that hill may or may not be a problem..
What you might want to look at is 2m SSB using
beams.. But again, the hills... ??
Those will be more of a problem, the higher in freq
you go I bet. Maybe it's time to upgrade, and use a
freq more suited, like 40 in the day, and 75 at night..
Actually, 75m will work that distance most any time
of the day.
If you can't have at least a good vertical on 10m, it
ain't gonna happen. Where as a low stealth dipole
would work on the lower bands, using NVIS propo.
Also, no power is needed in most cases.. 100w
is more than enough. 10w is plenty in many cases.
MK
Richard Harrison
"My parents are both techs so we`re currently limited to parts of 10m as
the lowest band and I`d like to have something available without
needing repeaters for disaster comms."
I`d like a million dollars too!
75 miles is reliably unlikely without a line of sight path between
radios at VHF unless expensive techniques are used.
A repeater located between the radios makes success much more likely.
Examine the ARRL "Repeater Directory" and borrow a hand-held (likely for
2-meters) and see which repeaters you can call up from both ends of the
path you would like to work. You will probably find you are in-business
but not for profit as it is amateur radio. For back up in emergencies,
you can use your cell phone or a wired phone.
Best regards, Richard Harrison, KB5WZI
Tom Ring
2m SSB or CW with modest power and antennas have a great chance of doing
what you wish.
A better description of the terrain would help.
2500 above mean average terrain? (I doubt that but have to ask)
A couple of hills. Sharp ridges? Above the line of sight?
Probably still quite doable. I used to work from Potsdam NY to
Plattsburgh NY (and a good chunk of Vermont) virtually every evening on
144.200 with a 12 foot yagi at 25 feet on my end, a 17 foot on the
other, using about 60 watts, and the Tug Hill Plateau and a couple small
mountains in the way.
2m "weak signal" is an often overlooked mode for 60 to 150 miles that is
very reliable for point to point.
tom
K0TAR
Tom Ring
Oh, 6 would work too, but 2 is easier and the antennas smaller yet.
tom
K0TAR
Owen Duffy
4ax.com:
Joey,
You have given a lot of information, and yet too little.
The distance you nominate can be a challenge, yet routinely possible on
frequencies from 28MHz to 440MHz, depending....
My thoughts are that simplex contacts will be unlikely without effective
outside antennas, though not necessarily directional antennas, but they
would help.
You note you may have access to several repeaters, than can certainly
equalise bad locations or impossible paths (eg granite), but then you
might not want to conduct family chat on repeaters (though that is they
way they seem to have gone here since many of our new six hour hams with
their shack on their belt seem to be family members). An FM repeater in a
very good location may support contacts reliably out to 150+km for each
station, depending...
Another possibility might be using IRLP build a path.
To give you an example, I can work the 2m repeater at Mt Ginini
(exceptional site) from the car on my driveway here at Narooma, 155km (~
95mi) over mountains etc (but we don't have real mountains here do we?),
it would be easier with a 5dB gain omni on the house.
I could use a handheld to make the trip to a repeater 90km (~56mi) away
and use IRLP to anywhere in the world (if I liked IRLP). Then by
contrast, there would be places where you couldn't work a repeater 10km
away with a handheld.
So, it may be that a path via a VHF or UHF repeater might be more viable
than 10m.
Perhaps some experimentation is in order, that is what ham radio was
about once.
Owen
John Smith I
Just off-hand, I would suspect for reliable and consistent
communications a three element yagi and ~100 watts on each end would
result in enjoyable rag chews ... same for 6m.
Height? More the better.
Seventy-five miles on omni antennas is very chancy, in my humble
opinion. But then, power/height would be the main variables, enough
height and power would certainly help.
Regards,
JS
P.Gregory
seriously its like asking how long do i cook bacon before its cooked....
"Joey" <jo...@nowhere.org> wrote in message
news:dd64339h0kluu9d5k...@4ax.com...
art
Hmmmm. I would think that going to a frequency such as 144 MHz would
be the way to go as radiation would tend to hug the earths
surface.With 28 MHz the height factor not only be impracticable (point
to point) but no amount of extra power is going to lower the TOA. When
my son was in a hospital over 100 miles away he used his hand held to
a local repeater and I used 10 watts with a directional antenna to the
distant repeater with intervening land less than 100 foot elevation
variance. Contact was always assured.
Art
Sal M. Onella
I have been on 10m myself lately, having just upgraded. I find it nearly
worthless for anything over fifteen miles. Without skip, you need an
elevated antenna, high ERP or both. 75 miles is inside the skip zone; that
is, if 10 were going to skip, it is still overhead at 75 miles and is going
to come down farther away.
Sure, investigate NVIS, but I think it needs a particular anntenna at *both*
ends.
If you're not committed to 10m, I would recommend 2m, since at least one end
can have a high gain antenna. I use a 13-element yagi for 2m at Field Day
and I routinely work dozens of stations 75 miles away (or more). We are in
southern San Diego County and I work Los Angeles all day and night on 35w
with the yagi at 20 feet. 2m is almost noise-free, too, both with respect
to QRM and to receiver noise in FM mode.
73
John Smith I
> ...
> Hmmmm. I would think that going to a frequency such as 144 MHz would
> be the way to go as radiation would tend to hug the earths
> surface.With 28 MHz the height factor not only be impracticable (point
> to point) but no amount of extra power is going to lower the TOA. When
> my son was in a hospital over 100 miles away he used his hand held to
> a local repeater and I used 10 watts with a directional antenna to the
> distant repeater with intervening land less than 100 foot elevation
> variance. Contact was always assured.
> Art
>
A couple of decades ago on 10 meters with a 3 element yagi and 100
watts, I frequently chatted with a grass valley station from a location
in calaveras county, a distance of over 75 miles as the crow flies (also
made a few contacts in San Francisco.) Antenna was 35 ft in the air and
the other guy in grass valley had a similar setup.
You never know, 'ya just never know ... but with two omni antennas, I
doubt it would have been done.
Now australia with an omni and a 100 watts? No problem with good sun spots!
JS
John Smith I
[...]
By the way, antennas never intimidated me much ...
The stacked 6 element hygain or mosley (modified CB antenna) on a 100
ft. tower with a ham m rotor was a real signal magnet and ionosphere
burner ... I still have that antenna leaning up against a shed in the
back 40 ...
Only real problem with that antenna was forgetting to face it into the
high winds in a storm and ripping the gears in the rotor.
Regards,
JS
John Ferrell
>
>I have been on 10m myself lately, having just upgraded. I find it nearly
>worthless for anything over fifteen miles. Without skip, you need an
>elevated antenna, high ERP or both. 75 miles is inside the skip zone; that
>is, if 10 were going to skip, it is still overhead at 75 miles and is going
>to come down farther away.
>
>Sure, investigate NVIS, but I think it needs a particular anntenna at *both*
>ends.
>
>If you're not committed to 10m, I would recommend 2m, since at least one end
>can have a high gain antenna. I use a 13-element yagi for 2m at Field Day
>and I routinely work dozens of stations 75 miles away (or more). We are in
>southern San Diego County and I work Los Angeles all day and night on 35w
>with the yagi at 20 feet. 2m is almost noise-free, too, both with respect
>to QRM and to receiver noise in FM mode.
>
>73
>
there before I go to any other band. Lately, I have had no luck. I
recall that a long time ago I worked an Italian station on 10 who was
on a holiday at the beach. He was using a quarter wave whip stuck in
the sand on the beach and 10 watts. He sounded like a local to me in
Ohio.
Sometimes an opening comes and goes like a summer breeze...
Sometimes the band is open and nobody knows until someone calls CQ!
John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"
Jimmie D
"John Ferrell" <johnf...@sprintmail.com> wrote in message
news:468933h1fpvnv0ts2...@4ax.com...
A very good description of 10 meters, I talked ro North Dakota from Florida
and thought the band was dead it was so quiet. I heard someone talking and
thought they were local at first. 10 M is a fun band.
Jimmie
Joey
between here and there... D'oh! I can use the big antenna on the
house here and hit quite a few more tho. Plenty of linked 440 systems
tho...
Joey
Joey
with a 2200ft ridge less than 5 miles away... back down to probably
1500 ft until... About 60 miles from here is the tallish 3500ish ft.
mountains and then its down basically to sea level for the remainder.
This does seem to produce a rather sharp angle at the both ends. So
much so that I have trouble hitting the 3500ft repeaters from here
without going up to the big antenna. I do remember hitting some
repeater off to the side of the direct path about 10 years ago with
just a handheld and some gainy portable antenna (don't even remember
which one)... but haven't been able to find it since! Doh!
I'll probably end up just finding some 2m stuff to work. We have a
few linked 440 systems (California) too...
Joey
On Fri, 27 Apr 2007 20:40:51 -0500, Tom Ring <news...@taring.org>
wrote:
Joey
It sounds like I pictured 10 meters as a lot lower that it really
is... Sounds like it's really VHF-like during low cycles .. I'll
probably go back to 2 or 440 and mess around tho there only a couple
repeaters on 2m but a bunch on 440 that are linked.
I am going to try to get at least my dad to upgrade to General tho. I
think he'd like to have something long distance while camping, and HF
is of course perfect for that :)
Yes, back to experimentation!!
Joey
ts o
Thanks for all who've responded... Good info!!.
The path I'm lookin for is Oceanside to Redlands, similar to San Diego
to LA, but we have the OC mountains in between... as well as those by
moreno valley...
Time to play with what I have....
Joey