[AMRadio] Receiver if alignment question

[jim and ella]

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
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