[R-390] Alignment question attenuator...
Rodney Bunt
[email protected]
Sun, 12 Jan 2003 16:58:06 -0800 (PST)
I built a 10:1 attenuator with 50 Ohm in an 125 Ohm out. So for any measurements just add -10db
for attenuation in the "matcher".
Here is the circuit.
10 db Attenuator
6 Ohm 97 Ohm
50 Ohm in 0----\/\/\/\/------0------/\/\/\/\/----0 125 Ohm out
|
|
\
/
\ 56 Ohm
/
|
|
0-----------------0------------------0
Rodney
VK2KTZ
--- Glenn Little <[email protected]> wrote:
> A google search for DA-121/u produces only three hits. The last is a thread
> from this reflector that shows how to build one. It consists of a 68 and a
> 100 Ohm resistom and is used as an impedance transformer.
>
> 73
> Glenn
> WB4UIV
>
> At 12:53 PM 1/11/03 -0500, Jim Brannigan wrote:
> >Hello All,
> >
> >I changed the 3rd mixer back to a 6C4, checked the mechanical alignment and
> >am now warming up the URM-25 and R-390A.
> >
> >For the RF alignment the manual refers to using an electrical dummy load, a
> >DA-121/U. This is not part of the URM-25 pack. Is this necessary or should
> >I just use a 50ohm load?
> >
> >If it is necessary, does anyone have the values used in the dummy load?
> >
> >Jim
> >
> >
> >_______________________________________________
> >R-390 mailing list
> >[email protected]
> >http://mailman.qth.net/mailman/listinfo/r-390
>
> ---------------------------------------------------------------------------
> Glenn Little [email protected] QCWA LM 28417
> Amateur Callsign: WB4UIV [email protected] AMSAT LM 2178
> QTH: Goose Creek, SC USA (EM92xx) EC Berkeley County ARRL TAPR
> ---------------------------------------------------------------------------
>
>
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