The AM Forum

I have blown the dust out ofthe homebrew rig. I gave it an on air test and set it on 7140 using a Crystal osc to put it spot on. It appears good. Power is decent(maybe 10 Watts). I will be leaving it at this freq for all ops till I am happy with the results. Audio will be a bit "Military" as I am using a WWII carbon Mic and circuit. Any sig reports would be welcome.
Don

Got a signal report from a SWL friend. Two in fact. He said he popped his RX on freq and emailed everytime he heard me. Carrier strong and solid but modulation too weak. At least I know the antenna and the parallel 6le6 PA is working well. He is far enuf away that if that was all it ever did as far as distance I would be content wth that. I will try boosting the mod today. If it wont do long distance with good mod then so be it. it works fine locally. I may dismantel it then and go back to the half finshed T1154 SMP build. Still learned a lot and made some personal progress. I am very pleased with the dual 6le6 PA. Works perfect. No current idle, jumps right to it on transmit. Good power and tunes sharpley.My own design, start to finish.
Don

You're not alone. There are plenty of stations out there running much more power whose modulation is lacking. It's an age-old problem. Distance isn't the issue - if you have a readable carrier, the modulation should follow suit. If you're not strong enough to hear, it's a non-issue, regardless.

Plug away at it, get it to where it works well, then use it and move forward with more power, if that's what you desire. We're moving into prime 40m evening operating time.

"  We're moving into prime 40m evening operating time. "

A bit off topic,

Here in C NY, 7290 was clear of oppressive foreign broadca$h stations.  I went to bed around 1AM, local time. As I threw the off switch, there was someone in New Mexico calling C Q.

klc

ou're not alone. There are plenty of stations out there running much more power whose modulation is lacking. It's an age-old problem. Distance isn't the issue - if you have a readable carrier, the modulation should follow suit. If you're not strong enough to hear, it's a non-issue, regardless.

I guess I have some learning to do. If i monitor the transmission it sounds fine even a mle away (so i am tild) but 100 miles away they say they can hear the carrier but no or very ilittle modulation. That doesnt make a lot of sense to me. I thought it would sound the same there as nearby only wealker. he said strong solid carrier.   I tested this rig against a real flea power which will barely wiggle the meter on my antenna tuner output indicator. This rig is it and i have to back off the meter's control to keep it in scale.
But yes i will plug away and figure it out. Anyway that is more tech then i wanted to say here.  I am good on 40 with my DX100 and have a 7290 rock so i may treatmuself tonite.

Don

I finally figured it out and got it working. I need a preamp I guess in my audio circuit. Not enuf gain. I know with my DX 100 I have to watch I keep my speech level up or guys in fringe areas can only hear my carrier. It finally dawned on me this AM rig is no different. Why would it be? Too soon old, too late smart.
I may get brave and try it Sunday on the 7120 group deal. In the meantime  am satisfied it is working fine. Got several  reports so I am satisfied for now. Thnks all who helped out.
Don

  don..what time are you on 40 in the evenings?...and when did you get a dx100?..
..tim..

..sk..

Ur right. I dont have a DX 100 I have a DX 60B. Been away from the shack too long.  I go down usually to the lower shack around 7 PM . Anything to avoid Wheel and Jepordy on TV.  Baring company or something unpreventable I will be there tonite.
Don

Tried 7140 tonite but K1KNM and the group have a party there on SSB. I read the mail for a bit and went on to other things.
I have been away from my radios all summer. Not only had I forgotten the model no I also have no idea now what crystals I have in the heathkit.
I know I have a 7290 and a 3705 . I fired it up and hooked up my 40M/80M inverted Vee and tuned it up on the morning freq you fellows used. I have even forgot what it was. It has been a busy summer and fall.
Anyway Nites are a wash on 7140.
Don

  Hi Don ; A fair bunch of guys are on in the mid afternoon around 3pm EST on 7295 or below weekdays. The optimal 40m daylight antenna seems to favor an NVIS 20 to 25ft up but verticals work too.Just get on the air and have some fun...We have low power stations break in from time to time. Hope I hear you in Ohio soon.   73 de n8aft

..don..did you get a better antenna up?..that would help greatly...i work 6 days a week, so i'm not on, in the mornings..maybe others are on 3725...some evenings i'm around, but frequently get home late...but the guys are on, sat/sun mornings on 3725...i call on sunday afternoons on 7120, around 4pm..

..tim..
..sk..

Nights are not a wash on 40. There is semi-regular, if not regular activity on 7290/95 many night. This activity has waxed and waned over at least the last 30 years.

For my upstairs station, no, I am on the same antennas but that is my goal before winter to triple the height. I will start on that tomorrow. Had a really busy and successful summer so much of my radio stuff lay dormant. Summmer prop isnt great anyway. My downstairs home brew rig I have been rubbing on. I have a not bad antenna there with some decent height just by virtue of the fact it is a walk out basement. I built a PA from a pair of 6L6EH tubes (parallel with tuned input/ tuned output) It is my own concoction but it tunes very cleany and smoothly. The Two tube Am rig drives it nicely and I pump it all through my homebrew HD tuner which gives me Pi  circuit or the traditional C circuit with or without L. I have found the sweetspot. I changed Mics on it as my No 3 hand mic gets tired after a bit . I have another military carbon mic that gives better voice quality. I spend about a 1/2hr a day calling. Sooner or later I will make a contact on it. I know it is working  since the SWL who gave me a surprise signal report by email also told me what I said. He lives north and east of Al. I am not going to fret over it. I will just keep pounding. It was like that with my CW rig too. Same output tube (50L6) I had it for years and worked away at it. One night a fellow challenged me to call on a specific frequency I did. I got 599 from Bangor Maine and Fletcher NC both. A lot of times one wants to blame the equipment but it is often a matter of oppourtunity.
First you need to both be on the same freq. You need to be in the same mode. In this case AM. You need to be at the right distance for current prop conditions. You need or I should say I need someone who is not obsessed with broadcast quality AM but who appreciates the spirit of building and operating ancient style stuff maybe even using a electromechanical carbon mike circuit which has very limited audio range. and last but not least you need someone who is not wondering who you are but decides to meet you. That alone is not as easy as it was when ham radio was fun. Last year I flopped around trying this and that and really got nowhere. I am making power . I have a reasonable level of modulation and I will keep at it till I get it working from down there. I shoose 7140 because I have a rock for it so I can mark the freq with my spotter Crystal osc and then tune right in with the rig. If I use the rigs recvr,(it is a four tube transceiver) I am within a minor RIT adjustment to be bang on. I also use a standby rx just in case. I also am getting ready to go back working on my T1154 SMP rig. It is about half done.
I will listen around when I am down in the cellar shack to those freq Steve and see if I cant find a spot. So far not a lot of AM heard but winter is coming and indoor sports pick up then. Ham radio and hopefully AM ham radio being one of them. This rig being relativily lowpower comlicates it but does not make it impossible. BTW Good talking to you this morning Tim.
Don   

One thing becomes obvious to me. There is no consistant AM activity anywhere. Tim VE6PG before his new job used to keep 80 active every morning. I still go there every day now this time of year.
Howrver on 40M if it is around I cant hear it so I will be on 7140 at 4 pm EST every day possible till spring. If your rig needs to get warmed up join me. I am no organizer , no net manager or anything but I will be there everyday possible.
Dont wait to hear me either just let me in when I call. 
If we want to keep AM active we have to use it on a regular basis.
Don

on 40-10M, you are right. But on 80 and 160, I can find AM activity every night on 3885, 3875, or 3705....and on 160 at 1885. The only time I don't hear anything is when the band is wiped out by static or bad propagation.

I heard two in there tonite. they were out of my range  but were definately two AM stations. I just back out and let it happen. The whole point is regular AM on 40 and they were there.

I have noted especially the 80M stuff. This rig is dualband .  Anyway 7140 I will be there.
Don
I am switchng to 7120. Tim has been bangng away there Sunday afternoons at 4 . iIwent there today. No cigar but that is just today.
Don

I have been working around 7120kc when possible. Not a lot of power but made some improvements today.
Don

Local time here is 3:40 PM.Will be testing on AM and calling CQ in about ten minutes on my Homebrew 2 tuber.  In and around 7115 to 7120kcs. If you hear me even weakly please come back.
Don

I built a driver circuit between my 2 tube am rig and my twin 6l6 amp. Power is up significantly (X10 )  "Power" being a relative term, so I will be working around 7120 at anytime I have a few minutes.   Hope to meet some of you there. 
Don

Tim I heard you and Mike this afternon. It was pretty noisy and in and out. igave it a shot but had not much hope. Noise level was probably above my power. I will leave it right there and listen when ever I am in the lower shack.
Don Ve3LYX