[R-390] Alignment

[Jim Temple]

Hi Roger,

Thanks for the pointers.  I'll holler if I run into any glitches.  I
appreciate your and the list's help in getting my receiver in shape.

Regards,

Jim
73, KF4ICZ

----- Original Message -----
From: "Roger L Ruszkowski" <rlruszkowski@raytheon.com>
To: <r-390@mailman.qth.net>
Sent: Monday, April 01, 2002 1:08 PM
Subject: Re: [R-390] Alignment


>
> I did the alignment, before my latest escapade, and it went well.
However,
> I estimated the 150uV needed to obtain the 7volts diode load.
>
> The signal generator is a Heathkit that has no meter, so the output is not
> calibrated.  I measure the frequency with an HP freq counter, so I have
> accurate frequencies.  I know that a calibrated output is not needed for
> any
> of the alignment, except to set the 7volts at 150uV.
>
> Can the 150uV output be accurately measured with a VOM??  I think the
> output
> to be measured is RF voltage, so would a small RF detector, such as what
is
> in the ARRL handbook be suitable and accurate enough for the purpose.
>
> Jim.
>
>
> Jim,
>
> Go read Chuck Ripples page on how to set the IF gain.
>
> Chuck Rippel, WA4HHG A "must see" collection of R-390A information
> http://www.r390a.com/
>
>
> A lot of owners do not have calibrated test equipment to
> set up the -7 volts.
>
> This procedure provides the best setting that really works
> in real life with your receiver at your Qth and your antenna.
>
> Roger.
>
>
> P.S.
>
> If you want to meter the Sig Gen. Then use a good tight metal box with
> high impedance detector (active amp) and meter. Put your own
> attenuator into the box. Measure the sig gen at full (near full) output in
> the
> meter box and then use your step attenuator to reduce the output to the
> level
> you need. Consider it easier to meter a big voltage than a small voltage.
> There is also the load impedance to consider in the metering.
>
> A scope that will get you down to mill volts (AN/URM 25 is only .2 volts
> max)
> and some math would let you measure the sig gen full voltage into a fixed
> load resistance.
>
> You may want to meter the signal gen one time at specific frequencies
> and then judge where to set the knob to get  about what you need.
>
>
>
>
>
> _______________________________________________
> R-390 mailing list
> R-390@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/r-390
>