At 03:58 PM 9/9/99 -0500, Jon Ogden wrote:
>Let's try to make some sense to this:
>
>1.) Do you have a dummy load? If so, try running the amp on the affected
>band into the dummy load. Does all work fine then?
>2.) What SWR do you get on your antenna when you run barefoot? Is the
>antenna SWR good or bad?
Barefoot most of the SWRs are good, 1.5-2.0:1. The exceptions are 3.0:1 in
the
high end 15mtr band (ca. 21.800mhz) and 5-8:1 in the 40 mtr band.
>3.) Does this phenomenon happen only on 15m?
No, this is occurring on all the bands.
>4.) When you say you are tuning the amp for low SWR, what does this mean?
Well, now you've got me thinking. maybe I have a misconception here. If
you mean to say
that any tuning of the AMP is merely for power and not SWR (SWR remaining
fixed), then I
admit I'm misusing the SWR/Power meter.
> Now that I think about it:
>
>An SWR meter is typically placed between a transceiver and an antenna
>tuner. The antenna tuner is then adjusted so that the SWR that the
>transceiver sees is good - typically less than 2:1. If the untuned SWR
>is 8:1, the tuner allows the transciver to see what appears to be a 50
>Ohm load. HOWEVER: THE SWR AFTER THE TUNER AND GOING TO THE ANTENNA IS
>STILL 8:1! Tuners do nothing to "tune" your antenna.
>
>Now for my question: When you tune your amp, where is your SWR/Power
>meter?
SWR/Power meter is after the AMP. Station layout is:
FT-840----->AMP.---->remote ant. switch box---->SWR/Power Meter
>Secondly, do you have antenna tuner
>between the amp and the antenna? If you do not have the tuner, then
>tuning the amp should NOT change the SWR after the amplifier.
No tuner. I don't think I should need it with pre-tuned TH7DX and M2 1el40
dipole.
Last thing I can think of: If your SWR meter is based on relative power
>as some of the Radio Shack meters are, you need to re-adjust your forward
>power setting (on the meter) before reading SWR. Relative power/SWR
>meters work by always setting the forward power reading to full scale on
>the meter and then switching to reading reflected power. I am not sure
>if you have this sort of meter or not.
Yes, I have that kind of meter. Made by RS. And yes, I do calibrate it.
In conclusion, it would seem that all of you are telling me that adjusting
the Amp
is only for proper loading and thus Maximum output, NOT for SWR! Is that
correct?
If so, thank you for setting me straight.
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|