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[email protected] March 10th 09 07:55 PM

Testing at higher frequencies
 
Does anyone know if there's a way I could test using an analyzer that
does about 50-500 MHz, but at a 1000-ish frequency? I need to test
something in that area, but I don't have equipment that will go that
high. Seems like any analyzer that goes that high is thousands of
dollars. Does anyone know if there's somebody that rents Anritsus in
SoCal maybe? Any suggestions are welcome. I mainly just need to do
SWR.

Thanks,

Jim Lux March 10th 09 09:07 PM

Testing at higher frequencies
 
wrote:
Does anyone know if there's a way I could test using an analyzer that
does about 50-500 MHz, but at a 1000-ish frequency? I need to test
something in that area, but I don't have equipment that will go that
high. Seems like any analyzer that goes that high is thousands of
dollars. Does anyone know if there's somebody that rents Anritsus in
SoCal maybe? Any suggestions are welcome. I mainly just need to do
SWR.

Thanks,

Test what? for what parameter? reflection coefficient? SWR?

There are lots of equipment rental places in southern California. google
is your friend. ElectroRents, Telogy, etc.

Something like the Anritsu SiteMaster? They're about $7000-8000 to buy,
so I'd expect a monthly rental (for short term) to be in the $700 range.

Jerry[_5_] March 10th 09 09:34 PM

Testing at higher frequencies
 

wrote in message
...
Does anyone know if there's a way I could test using an analyzer that
does about 50-500 MHz, but at a 1000-ish frequency? I need to test
something in that area, but I don't have equipment that will go that
high. Seems like any analyzer that goes that high is thousands of
dollars. Does anyone know if there's somebody that rents Anritsus in
SoCal maybe? Any suggestions are welcome. I mainly just need to do
SWR.

Thanks,


Do you have an amateur radio license? There are clubs in the Southern
California area.

Jerry KD6JDJ



[email protected] March 10th 09 11:28 PM

Testing at higher frequencies
 
I did find Electrorents. $700 for a month... I didn't think it would
be that much. It's mainly just for basic stuff, like SWR. I'm not a
ham. Seems like anything that goes past 500 MHz is really expensive.

dave March 11th 09 01:57 AM

Testing at higher frequencies
 
wrote:
I did find Electrorents. $700 for a month... I didn't think it would
be that much. It's mainly just for basic stuff, like SWR. I'm not a
ham. Seems like anything that goes past 500 MHz is really expensive.


What kind of power? You can use a Bird meter for VSWR.

dave March 11th 09 01:58 AM

Testing at higher frequencies
 
wrote:
I did find Electrorents. $700 for a month... I didn't think it would
be that much. It's mainly just for basic stuff, like SWR. I'm not a
ham. Seems like anything that goes past 500 MHz is really expensive.



http://birdtechnologies.thomasnet.co...ers?&forward=1

Bob Bob March 11th 09 11:08 AM

Testing at higher frequencies
 
A couple of options here. Not knowing your actual need for accuracy etc
makes it hard to guess!

From my standpoint I'd probably just adjust an antenna for max field
strength but if I wanted actual VSWR meaurement or minimizing same I'd
probably use a directioinal coupler and a sensitive voltmeter.

A DC is essentially the active component of a power/VSWR measuring
device. AT 1GHz I have seen PCB designs with SMA connectors that you
just put in circuit, measure the volts, reverse its direction, measure
the volts again and calculate the VSWR. Pretty simple and cheap stuff.
The biggest problem is preserving the impedance across the DC device
itself. You can use teflon PC board for example to help out on this. You
will also need to think about the calibration of the thing because the
diode is not a linear device and needs some volts to get over the
forward drop. You can also DC bias it but those components will affect
accuracy over temperature change etc.

Still a good general purpose tool though. You can even make loads that
would look like known impedances to calibrate the thing.

Have a look around for these. You'll be impressed by the low price. They
are after all just a lump of PCB, two connectors, a microwave diode and
a filter cap! You'll have to supply your own voltmeter!

Cheers Bob VK2YQA

wrote:
I did find Electrorents. $700 for a month... I didn't think it would
be that much. It's mainly just for basic stuff, like SWR. I'm not a
ham. Seems like anything that goes past 500 MHz is really expensive.


[email protected] March 11th 09 06:08 PM

Testing at higher frequencies
 
Thanks guys... Some of these ideas might work. Sorry, I should have
given more details... It's basically receive antennas in the 1000 MHz
range, and I don't have access to the transmitters that will be used
with them. I'm just trying to find a way to see where they're tuned
and then be able to tune them if they're off. So if I went with an SWR
meter, maybe there's an easy way to generate a signal to use that? I
have an Autek that goes to 500 MHz. Somebody mentioned using a
frequency doubler, but I'm not sure how that would work.

dave March 11th 09 07:23 PM

Testing at higher frequencies
 
wrote:
Thanks guys... Some of these ideas might work. Sorry, I should have
given more details... It's basically receive antennas in the 1000 MHz
range, and I don't have access to the transmitters that will be used
with them. I'm just trying to find a way to see where they're tuned
and then be able to tune them if they're off. So if I went with an SWR
meter, maybe there's an easy way to generate a signal to use that? I
have an Autek that goes to 500 MHz. Somebody mentioned using a
frequency doubler, but I'm not sure how that would work.


You need a spectrum analyzer with tracking generator option. Or a
network analyzer.

Jerry[_5_] March 11th 09 07:47 PM

Testing at higher frequencies
 

wrote in message
...
Thanks guys... Some of these ideas might work. Sorry, I should have
given more details... It's basically receive antennas in the 1000 MHz
range, and I don't have access to the transmitters that will be used
with them. I'm just trying to find a way to see where they're tuned
and then be able to tune them if they're off. So if I went with an SWR
meter, maybe there's an easy way to generate a signal to use that? I
have an Autek that goes to 500 MHz. Somebody mentioned using a
frequency doubler, but I'm not sure how that would work.


Hi

It has been my experience that the input impedance to the antenna can be
fairly well predictated by EZNEC is you are able to describe the antenna to
the program.

Jerry KD6JDJ




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