parameters governing the power rating and the frequency range of an SWR
meter


I am reading the article which was sent to me as a response to my question
about SWR meters and their construction. The article, a section of the test
equipment chapter of the RSGB VHF/UHF Handbook, explains the construction of
a reflectometer for 2m.

The main line pick up tube is selected to match the impedance of the antenna
line whereas the impedance of the sampling line can be more arbitrary and
just has to be matched up with the proper terminating resistor.

So much for impedance matching.


The article did not explain very much what the limitation of the device with
regards to the power and the used frequency are.

Ok, the power seems to be limited by the power rating of the resistors
terminating the sampling line.
But then what parameter(s) are reponsible for the frequency rating of the
device.

I am asking because at a local hamfest I picked up reflectometer parts and
now I wonder if I can change those to fit my needs (144MHz and low power).

regards Uwe

I was told the length of the sampler should be a very small
part of the wavelength of the frequency under test.

OTOH I have used a SWR meter intended for CB (27Mhz) on 2m
with success. Try it and see.

murray vk4aok

Uwe Langmesser wrote:

parameters governing the power rating and the frequency range of an SWR
meter

I am reading the article which was sent to me as a response to my question
about SWR meters and their construction. The article, a section of the test
equipment chapter of the RSGB VHF/UHF Handbook, explains the construction of
a reflectometer for 2m.

The main line pick up tube is selected to match the impedance of the antenna
line whereas the impedance of the sampling line can be more arbitrary and
just has to be matched up with the proper terminating resistor.

So much for impedance matching.

The article did not explain very much what the limitation of the device with
regards to the power and the used frequency are.

Ok, the power seems to be limited by the power rating of the resistors
terminating the sampling line.
But then what parameter(s) are reponsible for the frequency rating of the
device.

I am asking because at a local hamfest I picked up reflectometer parts and
now I wonder if I can change those to fit my needs (144MHz and low power).

regards Uwe

Yes yes, even one of those little Radio Shack SWR meters made for CB does
indicate "something", but somehow I want to make sure that it is relevant
before I attach a fine 2m transmitter and push the button.

regards Uwe



in article , Murray at
wrote on 2/14/04 9:59 PM:

I was told the length of the sampler should be a very small
part of the wavelength of the frequency under test.

OTOH I have used a SWR meter intended for CB (27Mhz) on 2m
with success. Try it and see.

murray vk4aok

Uwe Langmesser wrote:

parameters governing the power rating and the frequency range of an SWR
meter

I am reading the article which was sent to me as a response to my question
about SWR meters and their construction. The article, a section of the test
equipment chapter of the RSGB VHF/UHF Handbook, explains the construction of
a reflectometer for 2m.

The main line pick up tube is selected to match the impedance of the antenna
line whereas the impedance of the sampling line can be more arbitrary and
just has to be matched up with the proper terminating resistor.

So much for impedance matching.

The article did not explain very much what the limitation of the device with
regards to the power and the used frequency are.

Ok, the power seems to be limited by the power rating of the resistors
terminating the sampling line.
But then what parameter(s) are reponsible for the frequency rating of the
device.

I am asking because at a local hamfest I picked up reflectometer parts and
now I wonder if I can change those to fit my needs (144MHz and low power).

regards Uwe

Yes yes, even one of those little Radio Shack SWR meters made for CB does
indicate "something", but somehow I want to make sure that it is relevant
before I attach a fine 2m transmitter and push the button.

regards Uwe



in article , Murray at
wrote on 2/14/04 9:59 PM:

I was told the length of the sampler should be a very small
part of the wavelength of the frequency under test.

OTOH I have used a SWR meter intended for CB (27Mhz) on 2m
with success. Try it and see.

murray vk4aok

Uwe Langmesser wrote:

parameters governing the power rating and the frequency range of an SWR
meter

I am reading the article which was sent to me as a response to my question
about SWR meters and their construction. The article, a section of the test
equipment chapter of the RSGB VHF/UHF Handbook, explains the construction of
a reflectometer for 2m.

The main line pick up tube is selected to match the impedance of the antenna
line whereas the impedance of the sampling line can be more arbitrary and
just has to be matched up with the proper terminating resistor.

So much for impedance matching.

The article did not explain very much what the limitation of the device with
regards to the power and the used frequency are.

Ok, the power seems to be limited by the power rating of the resistors
terminating the sampling line.
But then what parameter(s) are reponsible for the frequency rating of the
device.

I am asking because at a local hamfest I picked up reflectometer parts and
now I wonder if I can change those to fit my needs (144MHz and low power).

regards Uwe

I was told the length of the sampler should be a very small
part of the wavelength of the frequency under test.

OTOH I have used a SWR meter intended for CB (27Mhz) on 2m
with success. Try it and see.

murray vk4aok

Uwe Langmesser wrote:

parameters governing the power rating and the frequency range of an SWR
meter

I am reading the article which was sent to me as a response to my question
about SWR meters and their construction. The article, a section of the test
equipment chapter of the RSGB VHF/UHF Handbook, explains the construction of
a reflectometer for 2m.

The main line pick up tube is selected to match the impedance of the antenna
line whereas the impedance of the sampling line can be more arbitrary and
just has to be matched up with the proper terminating resistor.

So much for impedance matching.

The article did not explain very much what the limitation of the device with
regards to the power and the used frequency are.

Ok, the power seems to be limited by the power rating of the resistors
terminating the sampling line.
But then what parameter(s) are reponsible for the frequency rating of the
device.

I am asking because at a local hamfest I picked up reflectometer parts and
now I wonder if I can change those to fit my needs (144MHz and low power).

regards Uwe