>
> Further - and this has gotten beyond the 160 meter scope of this list -
> 630 meter propagation will be almost entirely groundwave as ionospheric
> conditions generally do not support skywave (a primary reason for the
> use of LF and low MF for NDB). Since skywave is not supported, it
> makes
>
> Further - and this has gotten beyond the 160 meter scope of this list -
> 630 meter propagation will be almost entirely groundwave as ionospheric
> conditions generally do not support skywave (a primary reason for the
> use of LF and low MF for NDB). Since skywave is not supported, it
> makes
On 2/22/2012 11:04 AM, W2XJ wrote:
> I would disagree. The signal measured along the ground is affected
> by ground losses and is subject to ground conductivity even though
> the charts show maximum gain along the ground. The signal radiated at
> angles above about 10 degrees is governed by inver
Okay - I think we have hashed this one to death - thanks for the input, but
time to get back to topband related posts.
Thanks.
Tree
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
That is not what I said. The skywave would only be stronger if field
measurements on the ground were used to determine power due to various
ground losses, ground conductivity, etc. when an RF ammeter is used for
measurement (standard practice f
I would disagree. The signal measured along the ground is affected by
ground losses and is subject to ground conductivity even though the
charts show maximum gain along the ground. The signal radiated at angles
above about 10 degrees is governed by inverse distance and therefore
less loss. An att
Ahh but I think the FCC will see things much differently. I base this on
the existing 60M regs where an ERP is specified:
(i) No station may transmit with an effective radiated power (ERP)
exceed- ing 50 W PEP on the 60 m band. For the purpose of computing ERP,
the trans- mitter PEP will be mul
The maximum power radiated by a short monopole antenna system may be
calculated using equations found in standard engineering texts.
The link below shows a system with a 50 ft monopole radiating 1 watt EIRP on
630 kHz using the values shown for the r-f loss in the loading coil and r-f
ground co
> Fortunately, it is not true with short ground mounted monopole
> antennas. In order for the skywave to exceed the groundwave, the
> monopole needs to be longer than half wave (somewhere in the area
> exceeding 0.64 wave).
I believe Rich Fry pointed this out a couple months ago. The effect can
> If it is true that the skywave is stronger than the ground wave, then
> the power would need to be backed off,
Fortunately, it is not true with short ground mounted monopole
antennas. In order for the skywave to exceed the groundwave, the
monopole needs to be longer than half wave (somewhere i
This may be of interest to a few as applied to either band. Fritz was the
force behind getting the first experimental license and after a few years of
lobbying getting the ARRL to get behind it.
http://500kc.com/downloads/RN06-32.pdf
Carl
KM1H
WD2XSH/39
___
W2XJ wrote:
>
>
>
> If you can find a used FIM 22 it goes from 200 KHz to 550 KHz. That said
> I can not see determining EIRP by field measurement. There are just two
> many variables and a degree of engineering skill not posessed by the
> average amateur. The various national authorities must have
On 2/21/2012 4:17 PM, W2XJ wrote:
> In broadcast work the antenna impedance is first determined by
> calculation (now modeling) then the actual impedance are measured
> when the station is tuned up. Loading coils are not used at least not
> by that name.
The methods used in broadcast work are not
If you can find a used FIM 22 it goes from 200 KHz to 550 KHz. That said
I can not see determining EIRP by field measurement. There are just two
many variables and a degree of engineering skill not posessed by the
average amateur. The various national authorities must have a means of
measurement
On 2/21/2012 11:51 AM, W2XJ wrote:
> The Potomac Analog FIM is no longer available, nor are the parts to
> repair them and calibration service is no longer available. The new
> meters are expensive digital units. But in broadcast we do not use them
> to determine power but rather coverage usually w
In broadcast work the antenna impedance is first determined by
calculation (now modeling) then the actual impedance are measured when
the station is tuned up. Loading coils are not used at least not by that
name. The current is measured after the antenna matching unit which is
often a T network
W2XJ wrote:
> This method is virtually universal for MW power measurement. There are
> calibrated RF ammeters available since they are required at each AM
> broadcast station (directional stations may use as many as a dozen
> depending on the array). Alternatively the voltage can be measured. In
As I posted earlier field measurement is not an accurate method of
determining power. I seriously doubt an administration permit such a
technique unless it was very dumbed down and produced very 'safe'
results or in other words less power than could otherwise be achieved.
On 2/21/12 2:54 PM, Tod O
Joe, et. al
I am quite certain that there will need to be different sense antennas for
160m and 630m. I would not be surprised if we did not also need bandpass
filters for each of the bands as well.
As I recall there were several circuits in QST using a single analog
Devices unit to measure RF i
The Potomac Analog FIM is no longer available, nor are the parts to
repair them and calibration service is no longer available. The new
meters are expensive digital units. But in broadcast we do not use them
to determine power but rather coverage usually when directional systems
are tuned.
On
The link provided below shows how to calculate EIRP. I think each
administration will spell out the requirements of how to legally
calculate EIRP. To me it is fairly straight forward. 60M in the US is an
example. While there is an EIRP limitation, the FCC simplified the
determination by assumin
On 2/21/2012 8:26 AM, Joe Subich, W4TV wrote:
> > On Mon, 2012-02-20 at 19:04 -0700, Tod - ID wrote:
> >
> > The important thing is to have a way to assure that when someone
> > measured the same field at the same point with the same type of
> > measurement device they would get the s
I also think this topic is worth addressing, but Bill is probably
right in saying it could gobble all the bandwidth on this reflector.
Maybe someone would be willing to be the moderator of a new reflector.
In the mean time, we should acknowledge that a lot of the work has
already been done by the
> On Mon, 2012-02-20 at 19:04 -0700, Tod - ID wrote:
>
> The important thing is to have a way to assure that when someone
> measured the same field at the same point with the same type of
> measurement device they would get the same measurement result.
> That would allow us to compare measur
On Mon, 2012-02-20 at 19:04 -0700, Tod - ID wrote:
> In thinking about the measurement of EIRP for the new band it occurred to me
> that this might be the time for a few folks to think about how we could
> fabricate a "commonly calibrated" field strength meter. Such a device might
> well be used
You can get an absolute calibration by the reciprocity
method, using two identical antennas. An extension of
this technique is the 3 antenna method which gets rid
of the assumption that the antennas are identical, by
doing 3 pairs of measurements.
In the reciprocity method, you transmit on one sh
In thinking about the measurement of EIRP for the new band it occurred to me
that this might be the time for a few folks to think about how we could
fabricate a "commonly calibrated" field strength meter. Such a device might
well be used on both 160m and the 600 kHz band. By commonly calibrated
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