Similar to you, I found that the only way the RF-1 really helped in
matching the antenna was to tune the antenna to resonance where I
wanted it (minimum Z) and use the value of Z to construct the
appropriate matching network.
The component values for two component LC networks can be directly
computed from the formulas in ON4UN's book or elsewhere. One should
examine the two possibilities to determine which combination of L/C is
most buildable with components on hand.
This has never failed to work fine with a bit of tweaking afterwards.
73 de Brian/K3KO
Bowen, Arlan wrote:
> I have owned an RF 1 for several years. Initially, I tried to measure and
> convert the R and X readings, then build L networks to match by plugging my
> readings into L network program from ON4UN or the ARRL Antenna book. I
> finally gave up on that method because it just was not accurate enough.
> Sometimes it was not even close.
> On suggestion of AA4Z, I subsequently built a small universal network that
> can be made into any of 4, L network configurations. I put the L network
> right at the base of the vertical or at the end of a feedline where
> matching is needed. I then adjust the L network components to the proper
> configuration for a match. After that, I measure the values of L and C with
> the Autek and construct the network with heavy duty components.
> This method works correctly the first time, unlike my efforts to use
> measurements plus mathematics to get the values. In addition, it always
> gives the proper configuration for the L network, something that the
> "measured" numbers in the above programs, never provided. In the long run,
> this method is best and fastest.
> I use a small rotary inductor of about 18 microhenries and a large variable
> capacitor of around 1500 pF. The capacitor is an old 5 section one salvaged
> from military gear. You could also use a smaller variable and parallel
> fixed capacitors with a switch.
> The L network configurations are shown in ON4UN's Low Band book and in the
> ARRL Antenna Book, among others.
> INK N4OO
> At 02:51 PM 11/18/99 EST, you wrote:
> >I seem to have lost my manual for the Autek RF-1 analyst.
> >If someone was so great as to put one on a scanner and mail a copy (PDF) to
> >me - that would make me VERY HAPPY...!
> >otherwise... can someone tell me if and how can I measure complex impedances
> >(like 44 -j28 Ohms) with the RF-1? I think there was something explained in
> >the manual about how to combine results from Z measurements and L/C
> >measurements to find out the complex impedance...Or is this just wishful
> FAQ on WWW: http://www.contesting.com/towertalkfaq.html
> Submissions: email@example.com
> Administrative requests: towertalk-REQUEST@contesting.com
> Problems: firstname.lastname@example.org
> Search: http://www.contesting.com/km9p/search.htm
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Administrative requests: towertalk-REQUEST@contesting.com