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Back in the days of yore, when we were using super-regenerative
receivers, tube transmitters, etc. occasionally when being interfered
with, of just plain out of range, occasionally we could regain control
of the airplane by putting the transmitter on the roof of a nearby car,
thus providing a ground plane component. Sort of a court of last
resort, but, any old port........................Bill Glaze<br>
<br>
Michael Lance wrote:
<blockquote cite="mid002901c53fd6$e0f4ad90$6cde1218@c1870396a"
type="cite">
<pre wrap="">I remember that "situation", Steve. All of us witnesses were amazed
that you realized the issue, didn't over control and got your bird back
close enough to yourself to overcome the interference. The whole
sequence of events must have lasted close to a minute.
Amazing recognition of the problem and cool response; not sure how you
managed it.
MIke
-----Original Message-----
From: <a class="moz-txt-link-abbreviated" href="mailto:discussion-request@nsrca.org">discussion-request@nsrca.org</a> [<a class="moz-txt-link-freetext" href="mailto:discussion-request@nsrca.org">mailto:discussion-request@nsrca.org</a>]
On Behalf Of RC Steve Sterling
Sent: Tuesday, April 12, 2005 4:05 PM
To: <a class="moz-txt-link-abbreviated" href="mailto:discussion@nsrca.org">discussion@nsrca.org</a>
Subject: RE: Transmitter power questions.....
bare light bulb is pretty close analogy. Point source radiating in a
sphere
is the real definition.
A dipole actually has flux lobes and concentrates the radiated power
perpendicular (sorta) to the antenna, with nulls off the ends. Thus
dipoles
have that 2.1 db gain (theorically) over an isotropic source, because
they
concentrate more of the power broadside to the antenna. Although the
antennas on our transmitters are probably closer to being 1/4 wave whips
(still sorta a dipole), they don't have much energy coming off the
pointy
end. Still plenty to fly with in the normal situation. But if you ever
get
in a a weak signal or interference situation, holding the antenna
broadside
to airplane should raise the signal by several db. Helped me once in a
two
transmitters on situation.
-----Original Message-----
From: <a class="moz-txt-link-abbreviated" href="mailto:discussion-request@nsrca.org">discussion-request@nsrca.org</a>
[<a class="moz-txt-link-freetext" href="mailto:discussion-request@nsrca.org">mailto:discussion-request@nsrca.org</a>]On Behalf Of John Ferrell
Sent: Tuesday, April 12, 2005 11:39 AM
To: <a class="moz-txt-link-abbreviated" href="mailto:discussion@nsrca.org">discussion@nsrca.org</a>
Subject: Re: Transmitter power questions.....
That sounds familiar.
I have always thought of isotropic being like a bare light bulb
radiating
energy.
BTW, Bill & I defied fate again yesterday and flew all afternoon under
the
dreaded towers at CCRC....
John Ferrell
<a class="moz-txt-link-freetext" href="http://DixieNC.US">http://DixieNC.US</a>
----- Original Message -----
From: "Bob Richards" <a class="moz-txt-link-rfc2396E" href="mailto:bob@toprudder.com"><bob@toprudder.com></a>
To: <a class="moz-txt-link-rfc2396E" href="mailto:discussion@nsrca.org"><discussion@nsrca.org></a>
Sent: Tuesday, April 12, 2005 11:40 AM
Subject: Re: Transmitter power questions.....
</pre>
<blockquote type="cite">
<pre wrap="">John,
IIRC, the relationship between dipole and isotropic is
about 2.1 dB.
Now that you mention it, they probably run site
surveys to check for unauthorized transmissions and
that is why they want to know as much information
about the expected transmissions from on-base.
Bob R.
--- John Ferrell <a class="moz-txt-link-rfc2396E" href="mailto:johnferrell@earthlink.net"><johnferrell@earthlink.net></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">The antenna gain is less than 1 dbd. The last "d"
means as compared to a reference dipole. If needed,
I will review an antenna book for the relationship
to a "dbi" which is isotropic.
The polarization is not consistent since a hand held
whip antenna less than a quarter wave is being used.
The ground to air range is so low that the systems
can operate two miles apart without interfering with
each other. Since all of the equipment is handheld
and battery powered, no one is especially interested
in using the maximum legal power level.
BTW, IMHO, their vigilance in the matter of nearby
radio transmissions is commendable in these
unsettled time.
John Ferrell
<a class="moz-txt-link-freetext" href="http://DixieNC.US">http://DixieNC.US</a>
----- Original Message -----
From: Bill Glaze
To: <a class="moz-txt-link-abbreviated" href="mailto:discussion@nsrca.org">discussion@nsrca.org</a>
Sent: Monday, April 11, 2005 8:35 PM
Subject: Re: Transmitter power questions.....
I can answer a few:
Transmitter power: 1 watt maximum. Actual,
really about 200 milliwatts
Transmitter radius is difficult, because you need
to have an effective Field Strength Meter, but I
have successfully operated an airplane's controls at
1.1 miles, (line of sight) but I didn't intend to
fly; I couldn't even have seen the airplane.
Antenna used: Vertical Whip (Normally; that's
what's supplied)
Antenna gain; I don't really know the answer to
that one.
Polarization: Vertical (which is normal form a
whip antenna.)
bravo52 wrote:
Hey Guys,
I am working on a project to get RC on my Air
Force Base and they have a few questions........
Can anybody answer these questions for me given a
standard Futaba or JR radio?
1. What is the transmitter power?
2. What is the radius the transmitter will
operate effectively? Consider miles not
Line-of-sight. (I guess that depends on #1)
3. What type of transmit antenna will be used,
e.g., parabolic, whip, telescoping single pole, ect?
4. What is the transmitter antenna gain?
5. How is the transmit antenna polarized, e.g.,
horizontal, vertical, etc.?
TAI
v/r
Jerry L.
P.S. I tried to call Tony at RS but he left
early...............hmmm.......was he at the field????
</pre>
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