Hi,

I'm trying to determine if using an antenna analyzer is technically a
violation of the telecommunications Code of Federal Regulations. Typical
antenna analyzers inject a incident CW or sweeping CW to the antenna and
measure its return loss (reflection). Very few frequency bands have a CW or
sweeping CW as their allowed modulation type. The way I see it is that by
using an antenna analyzer you are intentionally radiating an improper
modulation type that was allocated for the band and therefore you are in
violation of the Code of Federal Regulations.

Anyone have any thoughts on this topic?

Thomas Magma

Thomas Magma wrote:
I'm trying to determine if using an antenna analyzer is technically a
violation of the telecommunications Code of Federal Regulations. Typical
antenna analyzers inject a incident CW or sweeping CW to the antenna and
measure its return loss (reflection). Very few frequency bands have a CW or
sweeping CW as their allowed modulation type. The way I see it is that by
using an antenna analyzer you are intentionally radiating an improper
modulation type that was allocated for the band and therefore you are in
violation of the Code of Federal Regulations.

Anyone have any thoughts on this topic?

By your logic a noise bridge would also be illegal. However in most places
there is a limit on the amount of power one can use before it requires
a license. Since an antenna analyzer puts out a few microwatts, if that,
no one seems to care.

I do not have the capability to measure the power level of mine, but I
expect that it is less than a regenerative receiver. It would be easy
to test, place one on an antenna and try to tune it in with a portable
receiver. If you can hear it, move away and see how far it goes.

Geoff.


--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/

"Thomas Magma" wrote in message
news:602zi.82535$rX4.27870@pd7urf2no...
Hi,

I'm trying to determine if using an antenna analyzer is technically a
violation of the telecommunications Code of Federal Regulations. Typical
antenna analyzers inject a incident CW or sweeping CW to the antenna and
measure its return loss (reflection). Very few frequency bands have a CW
or sweeping CW as their allowed modulation type. The way I see it is that
by using an antenna analyzer you are intentionally radiating an improper
modulation type that was allocated for the band and therefore you are in
violation of the Code of Federal Regulations.

Anyone have any thoughts on this topic?

Thomas Magma

Low power test gear is listed as a permitted form of radiation. While a
signal generator is permitted for use as a test instrument, it would not be
legal to use it for say a transmitter on a ham band that you are not licened
to use.
YOu could legally use it for a ham band transmitter if you followed all the
other part 95 rules.

Low power test gear is listed as a permitted form of radiation. While a
signal generator is permitted for use as a test instrument, it would not
be legal to use it for say a transmitter on a ham band that you are not
licened to use.
YOu could legally use it for a ham band transmitter if you followed all
the other part 95 rules.




Hi Ralph,
I don't mean to sound offensive, but do you know for a fact that low power
test gear is a permitted form of intentional radiation? I wonder what
constitutes 'low power'. Do you know where this is written so I can
research it myself?

Thanks,
Thomas

I'm trying to determine if using an antenna analyzer is technically a
violation of the telecommunications Code of Federal Regulations. Typical
antenna analyzers inject a incident CW or sweeping CW to the antenna and
measure its return loss (reflection). Very few frequency bands have a CW or
sweeping CW as their allowed modulation type. The way I see it is that by
using an antenna analyzer you are intentionally radiating an improper
modulation type that was allocated for the band and therefore you are in
violation of the Code of Federal Regulations.

Anyone have any thoughts on this topic?

By your logic a noise bridge would also be illegal. However in most places
there is a limit on the amount of power one can use before it requires
a license. Since an antenna analyzer puts out a few microwatts, if that,
no one seems to care.

My understanding is that the popular MFJ antenna analyzers generate
around 2 volts RMS of RF at their output port. This works out to
around 80 milliwatts into a 50-ohm load... comparable to what a small
QRP transmitter would deliver.

I do not have the capability to measure the power level of mine, but I
expect that it is less than a regenerative receiver.

I think that it's more than you might expect. These analyzers don't
use a tuned detector - they use a simple diode detector (admittedly
with low-threshold / "zero bias" Schottky diodes) and they need a
reasonably hefty signal. I've heard that there are some analyzers
which use some sort of mixer-and-filter arrangement to sample the RF
(thus allowing the analyzer to reject incidental off-frequency RF such
as the AM broadcast-band signals that render MFJ analyzers rather
useless on 80 and 160 meters) but I haven't seen one myself.

As to the issues of legality - IANAL, but I think that there's
probably a way to justify their use under the CFR.

For one thing: CW modulations are authorized under Part 97 on almost
all of the ham bands (everything other than 60 meters, I believe).
Stick to the bands on which you have operating privileges, and you're
probably safe there. Feel free to turn the analyzer on and off to
send your callsign in CW at the end of your test, if you're feeling
cautious :-)

For another: Part 97 specifically authorizes "test transmissions" on
any band authorized to the control operator (with restrictions on
pulse and spread-spectrum test transmissions).

For a third thing: it's quite possible that these devices would emit
a low-enough power level that they would qualify for use under Part 15
"intentional radiator" standards... and such devices are permitted to
operate in most frequency bands. Such devices to have maximum-power
limits, which are measured in microvolts-per-meter field strength at a
specified distance - limits and distances vary by frequency band.

For a fourth: they *might* also qualify for legal use under Part
18 (Industrial, Scientific, and Medical Equipment). These devices can
also operate in most frequency bands (although there are several
subbands which are specifically authorized for them and are thus
recommended), subject to maximum-field-strength limits similar to
those specified for Part 15 devices.

I doubt that the FCC has the inclination, desire, or resources to try
to forbid or limit the use of antenna analyzers. If they did, they'd
have to start raiding labs all over the country and confiscating
multi-thousand-dollar vector network analyzers, S-parameter test sets,
and so forth. The Benevolent Association of Agilent And Anritsu
Equipment Owners would no doubt start writing harsh letters to their
Congressmen :-)

In practice, I suspect that you're quite safe in using such devices as
long as you aren't causing harmful interference to licensed users of
the bands in question... and if you believe that you are, you should
of course cease transmission immijitly!

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

I doubt that the FCC has the inclination, desire, or resources to try
to forbid or limit the use of antenna analyzers. If they did, they'd
have to start raiding labs all over the country and confiscating
multi-thousand-dollar vector network analyzers, S-parameter test sets,
and so forth.

A network analyzers is not marketed as an antenna analyzer, or even an
intentional radiator for that matter. I have a signal generator, an
amplifier and an antenna in my lab but it does not mean I can sweep the
entire LF to UHF bands at any wattage.

For a fourth: they *might* also qualify for legal use under Part
18 (Industrial, Scientific, and Medical Equipment). These devices can
also operate in most frequency bands (although there are several
subbands which are specifically authorized for them and are thus
recommended), subject to maximum-field-strength limits similar to
those specified for Part 15 devices.

I was just looking through Part 18 and it really is unclear to me, however
one thing was clear to me, ISM devices are prohibited for use in certain
bands. One of which is search and rescue. So now how can I test my ELT
antenna installation on my aircraft if I'm violating FCC rules?

Thomas

Thomas you can start around here in the Part 15 rules.


[Code of Federal Regulations]
[Title 47, Volume 1, Parts 0 to 19]
[Revised as of October 1, 2000]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR15.3]

[Page 676-679]

TITLE 47--TELECOMMUNICATION

CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION

PART 15--RADIO FREQUENCY DEVICES--Table of Contents

Subpart A--General

Sec. 15.3 Definitions.


(dd) Test equipment is defined as equipment that is intended
primarily for purposes of performing measurements or scientific
investigations. Such equipment includes, but is not limited to, field
strength meters, spectrum analyzers, and modulation monitors.


"Thomas Magma" wrote in message
news:Ih3zi.82605$rX4.66763@pd7urf2no...

Low power test gear is listed as a permitted form of radiation. While a
signal generator is permitted for use as a test instrument, it would not
be legal to use it for say a transmitter on a ham band that you are not
licened to use.
YOu could legally use it for a ham band transmitter if you followed all
the other part 95 rules.




Hi Ralph,
I don't mean to sound offensive, but do you know for a fact that low power
test gear is a permitted form of intentional radiation? I wonder what
constitutes 'low power'. Do you know where this is written so I can
research it myself?

Thanks,
Thomas

Thomas Magma wrote:
I doubt that the FCC has the inclination, desire, or resources to try
to forbid or limit the use of antenna analyzers. If they did, they'd
have to start raiding labs all over the country and confiscating
multi-thousand-dollar vector network analyzers, S-parameter test sets,
and so forth.

A network analyzers is not marketed as an antenna analyzer, or even an
intentional radiator for that matter. I have a signal generator, an
amplifier and an antenna in my lab but it does not mean I can sweep the
entire LF to UHF bands at any wattage.

Then you need to get a better signal generator.

For a fourth: they *might* also qualify for legal use under Part
18 (Industrial, Scientific, and Medical Equipment). These devices can
also operate in most frequency bands (although there are several
subbands which are specifically authorized for them and are thus
recommended), subject to maximum-field-strength limits similar to
those specified for Part 15 devices.

I was just looking through Part 18 and it really is unclear to me, however
one thing was clear to me, ISM devices are prohibited for use in certain
bands. One of which is search and rescue. So now how can I test my ELT
antenna installation on my aircraft if I'm violating FCC rules?

You test it during the time window when testing ELT's is allowed.

Since such devices have been around in one form or another for longer
than most everybody currently alive and the FCC has shown no interest
in them to date, the empirical evidence is the FCC doesn't care about
them.

And for the nitpickers, yes if you hooked one to an antenna and left
it turned on for days, someone might start caring.

--
Jim Pennino

Remove .spam.sux to reply.

Dave Platt wrote:

My understanding is that the popular MFJ antenna analyzers generate
around 2 volts RMS of RF at their output port. This works out to
around 80 milliwatts into a 50-ohm load... comparable to what a small
QRP transmitter would deliver.


However my measurements of an MFJ-259B and an MFJ-269 both show constant
output throughout the frequency range of +7.0dBm +/- .5dB which is 5mW
and not 80mW.

73,
Larry, W0QE

In article ,
Larry Benko wrote:

My understanding is that the popular MFJ antenna analyzers generate
around 2 volts RMS of RF at their output port. This works out to
around 80 milliwatts into a 50-ohm load... comparable to what a small
QRP transmitter would deliver.

However my measurements of an MFJ-259B and an MFJ-269 both show constant
output throughout the frequency range of +7.0dBm +/- .5dB which is 5mW
and not 80mW.

Interesting - thanks, that's quite a bit lower level than I had
[obviously,mis-]remembered. That'd be about .5 volts RMS rather than
2 volts RMS, IIRC.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!