[AMRadio] Receiver if alignment question

Sun Jul 17 14:12:23 EDT 2011

Some RX call for stagger-tuned IF parameters.  You service monitor ought to
be able to display it in real time looking at the 2nd detector input whilst
generating the required RF.

                                          ---OR---

Some IF amps have a swamping resistor across the IF coils to improve B/W,
one may be open leading to audio distortion due to extreme narrowbanding on
hi-fi AM.

73DG

On Sun, Jul 17, 2011 at 10:55 AM, jim and ella <wb5oxq at grandecom.net> wrote:

> My monitor has a 3 position switch for modulation.  am-cw-fm  I am sure I
> had it in am.  However I may have had the modulation set too high.  The
> manual calls for 30%
> I will say that during the rf alighment part i was getting 1 microvolt
> sensitivity on all bands except 6 meters and the best it would do there was
> 3 microvolts.
> 1 microvolt on am is what the radio is rated for.
>
> ----- Original Message -----
> From: "Gary Schafer" <garyschafer at comcast.net>
> To: "'Discussion of AM Radio in the Amateur Service'"
> <amradio at mailman.qth.net>
> Sent: Sunday, July 17, 2011 9:18 AM
> Subject: Re: [AMRadio] Receiver if alignment question
>
>
> > Did you modulate the signal generator with FM rather than AM perhaps?
> Some
> > of the service monitors only did FM.
> > If so that would fit your description of what is going on.
> >
> > 73
> > Gary K4FMX
> >
> >> -----Original Message-----
> >> From: amradio-bounces at mailman.qth.net [mailto:amradio-
> >> bounces at mailman.qth.net] On Behalf Of Jim WB5OXQ inb Waco, TX
> >> Sent: Sunday, July 17, 2011 1:10 AM
> >> To: Discussion of AM Radio in the Amateur Service
> >> Subject: [AMRadio] Receiver if alignment question
> >>
> >> I am trying to make sure the vintage tube receiver I bought is aligned
> >> properly.
> >> I have the manual that came with the radio and it has alignment
> >> procedure in it which I followed.
> >> My question is in regards to the if alignment for the single conversion
> >> 455khz if.
> >> The instructions begins with removal of the 6aq8 oscillator tube from
> >> its socket and connecting the generator to pin 7 of the 6be6 mixer tube
> >> and ground.
> >> Set the generator to 455khz with 400hz modulation at 30%.  connect a ac
> >> voltmeter across the speaker.  Set the avc to off.
> >> Now I have a signal and tone in the speaker from the generator ( my
> >> Motorola am fm service monitor) and if I adjust the if coils in the
> >> order stated in the manual this is what I get;
> >> adjusting the 2 if coils each with a primary and secondary  I get the
> >> loudest volume and highest meter reading but when I do the signal sounds
> >> miss tuned and raspy.
> >> of I tune for the purest tone the volume is much less.  So which is
> >> correct?  Higher volume or clearest tone?
> >> The adjustments were way off from where I found them originally.  I
> >> doubt the factory alignment was that bad but who knows what any previous
> >> owner might have done?
> >> There is a scope in the service monitor but I did not use it and only
> >> used the voltmeter.  Would the scope be better?
> >> I followed up with a complete alignment of all 5 bands so dial
> >> calibration is extremely good now but I just don't seem to get the
> >> quality of audio I feel I should be getting.
> >> Broadcast stations sound overloaded even with the avc on to the point I
> >> have to turn the rf gain nearly to 0 on local am stations and there seem
> >> to be an abnormal amount of birdies on all the bands.  Weaker stations
> >> on any band seem ok.
> >> This receiver is a 1965 Lafayette HE 80 built by Trio in Japan
> >> (Kenwood).  It is a 14 tube receiver with a built in 6 meter converter
> >> and is an all mode receiver.  It does receive ssb stations fairly well
> >> on 6 meters on a poor antenna for that band but there are lots of
> >> birdies on that band.   I just wonder if I misaligned the IFs and that
> >> is causing oscillations where they should not be?
> >> Any advice will be appreciated.
> >> Jim wb5oxq
> >> ______________________________________________________________
> >> Our Main Website: http://www.amfone.net
> >> AMRadio mailing list
> >> Searchable Archives: http://www.mail-
> >> archive.com/amradio at mailman.qth.net/
> >> List Rules (must read!): http://w5ami.net/amradiofaq.html
> >> List Home: http://mailman.qth.net/mailman/listinfo/amradio
> >> Post: AMRadio at mailman.qth.net
> >> To unsubscribe, send an email to amradio-request at mailman.qth.net with
> >> the word unsubscribe in the message body.
> >>
> >> This list hosted by: http://www.qsl.net
> >> Please help support this email list: http://www.qsl.net/donate.html
> >
> > ______________________________________________________________
> > Our Main Website: http://www.amfone.net
> > AMRadio mailing list
> > Searchable Archives:
> http://www.mail-archive.com/[email protected]/
> > List Rules (must read!): http://w5ami.net/amradiofaq.html
> > List Home: http://mailman.qth.net/mailman/listinfo/amradio
> > Post: AMRadio at mailman.qth.net
> > To unsubscribe, send an email to amradio-request at mailman.qth.net with
> > the word unsubscribe in the message body.
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >
> >
> >
>
>
> ______________________________________________________________
> Our Main Website: http://www.amfone.net
> AMRadio mailing list
> Searchable Archives: http://www.mail-archive.com/[email protected]/
> List Rules (must read!): http://w5ami.net/amradiofaq.html
> List Home: http://mailman.qth.net/mailman/listinfo/amradio
> Post: AMRadio at mailman.qth.net
> To unsubscribe, send an email to amradio-request at mailman.qth.net with
> the word unsubscribe in the message body.
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>