[HCARC] NVIS - Local 10 meter Propagation Test

Thu Jul 26 21:16:20 EDT 2012

I may be getting ready to show my complete ignorance of how antennas work 
and radio in general, but wouldn't a simple dipole cut for 10 meters ( +/- 
17-18 feet) mounted low to the ground radiate pretty much straight up and 
take advantage of NVIS.  They say NVIS is good for up to 300 miles, but 
should cover everything that the members of the club need to talk on 10 
meters.  I say I show my ignorance because I still don't have radio number 
one and won't for several more months - barring the tooth fairy dumping a 
large sum of $$$ under my pillow.  I am saving, but I'm not getting there 
fast.  I am patient though.

I noticed a comment also in one of the emails that to include Center Point 
and Fredericksburg you would have to use at least General Class Freq.   I 
think this is the quote "Unfortunately, it appears we may need to consider 
the General class license operating frequencies to obtain the geographical 
area coverage required for communications with our members."  Those of us 
who have General Class Licenses would surely appreciate that - I know that I 
don't want my first QSO on a new radio to be with Fred telling me I am 
transmitting out of my authorized band.   I assume also that when you all 
are discussing 10 and 6 meters you are talking about SSB vs FM.  I know 
there are a few members (Techs ???) who have quad band tranceivers (23 cm 
through 10 meters) such as the Yaesu 8900, which turns out to only be an FM 
radio, incapable of SSB anywhere.

Those of us who are just starting out and those of us who are not Extras 
(YET), really appreciate you all thinking of us when you design a net.  It's 
nice to be included - we might just learn something.

BAAAAAAA!!!

Gary J
N5BAA
Texas Red Sheep Radio

----- Original Message ----- 
From: <galeheise at windstream.net>
To: "HCARC Reflector" <HCARC at mailman.qth.net>
Sent: Thursday, July 26, 2012 4:21 PM
Subject: [HCARC] Fw: Local 10 Meter Propagation Test - Tonight - 6:30 
to6:45 -28.365 Mhz

> To All-
>
>  I've had great responses from people interested in a local HF session.  I
> received a phone call last night from a member who expressed his interest 
> in
> a loosely structured rag chewing session.  Today, Kerry sent me the
> excellent email below.  Unfortunately, it appears we may need to consider
> the General class license operating frequencies to obtain the geographical
> area coverage required for communications with our members.  Possibly we
> should have a survey of members at our next club meeting to determine:
>
> 1.  Do members prefer meeting during the day or in the evening?
> 2.  While we may need to run more tests, it appears to include
> Fredericksburg and Centerpoint we may need to use 14 Mhz or lower
> frequencies.  Is there a band that meets this requirement and most members
> have antennas for the band?
>
>  I appreciate the interest of all those pursuing this issue.
>
> Gale
> KM4DR
>
> -----Original Message----- 
> From: Kerry Sandstrom
> Sent: Thursday, July 26, 2012 12:15 PM
> To: galeheise at windstream.net
> Subject: Re: [HCARC] Local 10 Meter Propagation Test - Tonight - 6:30 to
> 6:45 -28.365 Mhz
>
> Gale,
>
> I checked the ARRL Antenna Book, 18th Edition.  On page 23-4 Figure 3 is
> "Typical HF ground-wave range as a function of frequency".  It shows the
> following distances :
>
>    Frequency         Distance (miles)
>
>        30                            10
>
>        28                            12
>
>        21                            20
>
>        14                            30
>
>        10                            37
>
>          7                            45
>
>          4                            58
>
>          2                            90
>
> Unfortunately, no indication of the stations capabilities that should 
> expect
> these typical distances.  In the text it says that "the surface wave is of
> little value in amateur communication, except possibly at 1.8 MHz.
> Vertically polarized antennas must be used, which tends to limit amateur
> surface-wave communication to where large vertical systems can be 
> erected."
> I'm not sure I believe very much of this!  We heard each other very well
> during the test at what is supposedely the limit of the 'typical' range
> inspite of a vertical antenna on one end and a dipole on your end.  In 
> spite
> of the above statements in the Antenna Handbook, the ARRL has encouraged
> using ten meters for local nets since at least the 50's.
>
>>From the chart, it looks like 80 and 40 are the best choices if our guys 
>>can
> get antennas going for those bands.  Unfortunately, after dark, both bands
> get fairly crowded.  Ten certainly is the right choice for after dark but 
> we
> need to figure out what the station requirements are.  There are a couple
> mysteries from the test.  Harvey certainly had a good signal with his low
> dipole here, but I don't understand why he couldn't hear me better.  John
> was workable here on his high antenna, but I think he should have been
> stronger.  The radio line of sight for a 100' antenna is over 30 miles.
> Even with the terrain between us, we should have been close to line of
> sight.  If Bob was using his vertical, he should have been at least as
> strong as Harvey, if not stronger since he is closer to me and our
> polarizations match.  Oh well, that is why we need some experiments!
>
> At work I do a lot of propagation modeling.  I have several models that I
> can run.  Not one of them does HF surface/ground wave.  The ones that do 
> do
> surface wave and near earth propagation are 30 MHz and up.  The ones that
> use the ionosphere are all HF only.  There are some MF models that do 
> ground
> wave but are all AM broadcast band oriented.  We really are in an area 
> that
> most people aren't interested.
>
> Experiments that would be nice:
>
>    80/40 meters in the daytime
>
>    Vertical vs. horizontal on 80 and 40 meters
>
>    Vertical vs. horizontal on 10 meters
>
>    15 meters vs. 10 meters
>
> How did my audio sound during the test?  It was the first time I've had it
> on SSB.  I was using an old Shure mobile mike, probably crystal/ceramic.
>
> I only have a cell phone these days, my number is (830) 998-5203.
>
> Kerry
>
>
>
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