"Tarmo Tammaru" wrote in message ...
You don't say what VHF frequency, but the Cantenna is probably unsuitable at
that frequency. Your amp is spec'd to put out 300W into 50 Ohms, not 35 or
70. It could put out more or less power into a different impedance. Your
best bet is to build a little L network right at the Cantenna, adjust it for
1:1 SWR, and then measure the power. Another approach would be to string all
the RG58 you own in series with the 8X.

Tam/WB2TT

Less than 150 MHz. Someone else suggested that i place the meter
right at the cantenna, to at least exclude the patch from meter to
dummy load.

Unfortunately, as i have mentioned before, the cantenna is not the
greatest 50 Ohms at anything above 10-20 MHz.

Slick

"Dr. Slick" wrote in message
om...
Someone else suggested that i place the meter
right at the cantenna, to at least exclude the patch from meter to
dummy load.

No, you don't want to do that. Put as much loss as you can between the meter
and the Cantenna. 100 feet of RG58 will have about 6.5 db of loss. It will
make your load a lot closer to 50 Ohms. There are Tables that show SWR as a
function of cable loss for a given mismatch. One chart that I have in
"Reference Data for Radio Engineers" shows that with a load SWR of 1.4, and
6.5 db of cable loss, the SWR at the driving end is around 1.075. Note that
you DO NOT want low loss coax.

Tam/WB2TT

"Tarmo Tammaru" wrote in message ...
"Dr. Slick" wrote in message
om...
Someone else suggested that i place the meter
right at the cantenna, to at least exclude the patch from meter to
dummy load.

No, you don't want to do that. Put as much loss as you can between the meter
and the Cantenna. 100 feet of RG58 will have about 6.5 db of loss. It will
make your load a lot closer to 50 Ohms. There are Tables that show SWR as a
function of cable loss for a given mismatch. One chart that I have in
"Reference Data for Radio Engineers" shows that with a load SWR of 1.4, and
6.5 db of cable loss, the SWR at the driving end is around 1.075. Note that
you DO NOT want low loss coax.

Tam/WB2TT


Perhaps you are correct. That you would only want to use the
meter right at the load if you wanted to measure the real SWR of the
antenna, as the coax loss will improve the return loss (SWR).

I'll try a long piece of RG-58 and see how the incident power is
affected.

Slick

That would give you 13db of return loss which would be an SWR less than 2:1
even if the far end was a dead short.
Given his current SWR I woud say this would result in a return loss of
around 30db. Numbers are a lot of by guess and by golly but think I am not
too far off.
"Tarmo Tammaru" wrote in message
...

"Dr. Slick" wrote in message
om...
Someone else suggested that i place the meter
right at the cantenna, to at least exclude the patch from meter to
dummy load.

No, you don't want to do that. Put as much loss as you can between the
meter
and the Cantenna. 100 feet of RG58 will have about 6.5 db of loss. It will
make your load a lot closer to 50 Ohms. There are Tables that show SWR as
a
function of cable loss for a given mismatch. One chart that I have in
"Reference Data for Radio Engineers" shows that with a load SWR of 1.4,
and
6.5 db of cable loss, the SWR at the driving end is around 1.075. Note
that
you DO NOT want low loss coax.

Tam/WB2TT