Allwave 23 RF alignment

[Thomas Day]

The directions for the RF alignment of the Allwave 23 say that you connect the generator to the antenna terminals thru the "proper dummy". Capacitor? value? For all of the alignments I have done over the years, I have simply connected the generator to the antenna terminals with out any thing in between. Also I like the new format of the list. Easy to read.

Thom

[Dave Satterness]

Check this link for explanation and schematic for "Dummy":

http://www.ai4fr.com/main/page_electronic_repair_rma_schematic.html

B/r

Dave

[Dave Satterness]

Here is another link with more information.

http://www.antiqueradios.com/forums/viewtopic.php?t=33500

B/r

Dave

[Thomas Day]

Thanks for this information. Most of my experience has been with newer radios that have their own antenna, or FM systems and generators that have the standard 300 or 50 ohm output Z.

Thom

[David C. Poland]

New  info to me.  I now have an older solid state HP frequency generator (heavy and the size of a 1979s stereo receiver) .  Even with this HP sg gen  I should make the suggested RMA dummy antenna to improve the matching of my HP to the radio designed for a long wire antenna (a Scott) ?. The purpose being to avoid  mis-alignment.

Are we talking a noticeable alignment difference in practice?  

This impact the IF alignment and IF diode too or just the RF stage?

If I locate a 1/2 inch diameter hollow tube, any reason not to mount the capacitor inside the tube? 

[Thomas Day]

All good questions. I was a bench tech for Heathkit in the late '60's thru '74. We used a Boonton  202H RF generator for FM. AM was a Heathkit generator. The AM sections of most of their Hi Fi receivers were average at best, altho some of the separate tuners were very good. For the FM, you could usually get the sensitivity down to 1.8 microvolts, which was their specification. Then someone decided that the femtowatt was the way to measure FM sensitivity. Never did figure that one out. For the Scott, the dummy would only affect the RF section. The IF is isolated enough to not be affected by the RF alignment. For the dummy, leads should be as short as possible.

Thom