The AM Forum

Band Watch => 20 Meters => Topic started by: n4joy on February 09, 2015, 08:07:18 PM



Title: Nice 20 Meter AM QSO tonight...
Post by: n4joy on February 09, 2015, 08:07:18 PM
Tonight was the first time I've been on 20 meter AM in many, many years.  I had a nice chat with W9AD and KB1VWC.  Both stations had fairly strong signals and sounded great!  I was using my... get ready... National NCX-3 on AM.  Sounded very good for SSB carrier inserted with a D-104.  I'm very pleased to know there is some regular AM activity on 20. 

Chris, N4JOY

 


Title: Re: Nice 20 Meter AM QSO tonight...
Post by: KX5JT on February 10, 2015, 01:17:26 AM
14.286 or 14.330 ??


Title: Re: Nice 20 Meter AM QSO tonight...
Post by: n4joy on February 10, 2015, 06:41:25 AM
We were on 14.330 (actually a few kc down or so). 


Title: Re: Nice 20 Meter AM QSO tonight...
Post by: WA2ROC on February 10, 2015, 06:53:10 AM
Earlier. we were on 14.328 or so talking to KD6OS Ralph, W1LYD in Arizona and several others.  Our group went QRT probably just before you folks got on the air.

Ralph started out on that frequency to avoid the YL SSB net just above 14.330, where we usually hang out.

Hope to hear y'all next week


Title: Re: Nice 20 Meter AM QSO tonight...
Post by: n4joy on February 10, 2015, 01:19:23 PM
That makes sense--I heard a little bit of your QSO while I was letting National warm-up.  I didn't get all the call signs though and had a light copy on Ralph.

I will definitely check-in next week.  I'm debating whether to use the National again or maybe my recently restored Hallicrafters HT-40 with an amplifier.  The NCX-3 was pushing 100 watts input on AM (150 ma plate per instructions at 700 volts).  Next project will be adding a fan.  I'm still very surprised that the audio reports were so good for SSB with carrier but I typically get very good audio reports on SSB with the D-104.  AM receive is narrow so I generally tune a little of frequency to reduce muffle.


Title: Re: Nice 20 Meter AM QSO tonight...
Post by: Pete, WA2CWA on February 10, 2015, 02:52:14 PM
The NCX-3 was pushing 100 watts input on AM (150 ma plate per instructions at 700 volts).  Next project will be adding a fan.  I'm still very surprised that the audio reports were so good for SSB with carrier but I typically get very good audio reports on SSB with the D-104.  AM receive is narrow so I generally tune a little of frequency to reduce muffle.


I wouldn't run any more then about 25 or 30 watts carrier on AM, or in a short time, you can kiss your finals bye.
If I remember correctly, receive and transmit go through the SSB filter, so tuning off to the side is normal.


Title: Re: Nice 20 Meter AM QSO tonight...
Post by: kb3ouk on February 10, 2015, 08:24:24 PM
He said 100 watts input, and if that rig has a final amplifier that is a linear amplifier, like any other SSB rig of that time, that would work out to be 25 or 30% efficiency, which is 25 or 30 watts of carrier. My FT-901DM runs about 65 watts input and makes about 15 watts output when run at rated power.


Title: Re: Nice 20 Meter AM QSO tonight...
Post by: n4joy on February 11, 2015, 08:28:55 PM
That's correct: 100 watts input.  Per my manual:

[150ma] corresponds to approximately 100 watts input to the final amplifier, thus assuring operation of the final amplifier tubes within their plate dissipation rating.

I try to go easy on the sweep tubes and avoid long winded transmissions on AM.  Anyway, it was fun to give it a go and find out how she sounded on the air.


Title: Re: Nice 20 Meter AM QSO tonight...
Post by: Pete, WA2CWA on February 11, 2015, 09:46:20 PM
I don't use my NCX-3 or NCX-5 on AM. The AM receive hurts my ears. Everyone sounds like they're chewing on a sock. Unfortunately, the NCX-3 also has no RIT which can be a pain on SSB. I've used these rigs for years and occasionally check into the vintage SSB net with them.
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