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Is 200w enough for 75 AM in the midwest?

Discussion in 'Amplitude Modulation' started by K8CCA, Mar 13, 2019.

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  1. K8CCA

    K8CCA Ham Member QRZ Page

    Hey thanks for all the comments guys! I made my first AM contact last night after work. I fired up the IC-7300 and Drake L4B. Was able to tune for 150W output, (L4B has new caps and new tubes) but then backed it off to 100w after we got gabbing as the 3-500z where pretty red. I have never seen them like that, lol. Had a blast, an hour long QSO with 5 guys. I really enjoyed it. Got real motivation to get my Valiant on the air now. Ran the IC-7300 at 20w and it seemed happy.

    @ Dave - I had a 753 as my first HF rig, it was a challenge to operate CW. I was just starting out, trying to get my 13WPM so I was all over the 40meter novice CW band working to get my speed up. It and it drifted so bad that a few times I was told I was out of band, but it had just drifted there as the previous contact I was in band, lol. I later upgraded to a HW-101 and that was a huge upgrade, lol
    WA3VJB likes this.
  2. WB2GCR

    WB2GCR Ham Member QRZ Page

    That modified Valiant?
    Why not open it up and show some pix of the innards?
    Does it have sweep tubes for the modulators?

    I'd run that one.

    Take the xfmrs out of the good one and sub them in...
    Of course, you'd have to figure out what was done.
    The HV xfmr may have been "over taxed" which is why it shorted.
    In which case, you may need to figure out the current draw on keydown
    and see if ur over current... Worst case pull one 6146, go back to 3.

    Short of that run the stock one - then do some judicious mods.

    Pull the iron off the one that has it and put it on the other one.

    The 7300 is ok into the linear... but it's second best to the Valiant, imho.

  3. K8CCA

    K8CCA Ham Member QRZ Page

    yeah, I think I am going to order the LV transformer.

    Here are some pics of the one with the short HV xfmr.

    When I started the VFO didn't work, the bias was hooked up wrong, and there was a 4th PA tubes added. I should have just moved the LV transformer back to the one that was missing, and looks unmodified, but I had already recapped this one, so I kept moving forward.





    And the missing LV xfmr on the second one

  4. WB2GCR

    WB2GCR Ham Member QRZ Page

    Sorry, not sure what I am seeing?
    I'm not seeing a place for a 4th RF final tube?
    In any event, that front panel does look nice.

    You might just look at the specs for the missing LV iron, and look at epay,
    A bit of old mfrs catalog reading, I was able to find excellent replacements for
    the R-388/51J-3 power transformer, for example. New in the box. Stancor, Triad,
    Chicago, Thordarsen, etc... might save a few $$, dunno.

    A wide shot from above and below the two chassis would reveal a lot of information, fwiw.
  5. W2VW

    W2VW Ham Member QRZ Page

    How do you know there's a short in the HV xfmr?

    The DC plate blocking capacitor looks like it has a crack which can be a sign of a short.

    WB2GCR likes this.
  6. N2DTS

    N2DTS Ham Member QRZ Page

    What is that tube jammed next to the modulator tube?
    WB2GCR likes this.
  7. K8CCA

    K8CCA Ham Member QRZ Page

    Boy I don't know what that extra tube is. Whoever had these sure did like to mod them. I hate these rack handles on the face. I can't imagine drilling holes in the front of cabinets like that. Both are like that. I had also got a Johnson 500 with this stuff, that had the same rack handles and a few other holes drilled in it. The pics above are of the one missing the LV transformer, so I never fired it up. I will get some pics of the one that I have been working on soon. Maybe you guys and your eagle eyes can help me fix it. Maybe the xfmr is not bad. Check back later this weekend!
  8. K8CCA

    K8CCA Ham Member QRZ Page

    Ok, here are the pics of the Valiant that pops fuses upon turning plate on. I had the 3B28 plate caps removed and taped up seeing if that was the issue.







    Here is the Vintage desk

    W4KJG likes this.
  9. W4KJG

    W4KJG Subscriber QRZ Page

    You should have plenty of AM "uumphf" with what you have described. I grew up at the western end of Lake Superior. I'm young enough to have lived through the days when AM was King.

    Operation was different. IMO the HF bands were much more crowded than they are today. Hetrodynes were at every minor turn of a receiver's bandspread knob.

    But, regional AM communication on 75 and 40 was extremely popular. Most of us knew dozens of others quite well. It was like the Facebook of the late-50s/early-60s. Old timers, and those of us youngsters in those days, got along quite well with each other. As teens, us kids from Upper Michigan, Northern Wisconsin, Northern Minnesota, the Eastern Dakotas, Southwestern Ontario, and Southeastern Manitoba had many QSOs going every afternoon and evening after school. We got together at each other's cabins for fishing and family gatherings. We got together for dances, concerts, hamfests, etc.

    We ran DX-40s, Johnson Rangers, etc., and really big rigs like DX-100s and Viking IIs. Very few ran over 100 watts output. We somehow talked for hours.
  10. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    In the late 1950s into the early 1960s, after school, in the Midwest, there was a large group of high school aged operators who would get on 7290 kHz. Those of us with the "big" rigs (DX-100, Apache, and Viking II) would hold the frequency for the DX-35, DX-40, Globe Scout, Ranger, etc., operators until about sundown. Then, the shortwave broadcasters would take over and even those running full legal power would have problems.

    We just used our cerebral filters and ignored heterodynes and other interference. Seldom was there no interference and we did not really expect no interference! Unlike today where a significant number of operators seem to have the position that they are entitled to have a completely clear frequency.

    There are times when I believe that every newcomer should have to use, for the 1st year of operation, typical receivers from the 1950s into the 1960s. The receivers that were "broad as a barn" in selectivity, drifted, were almost deaf above around 10 MHz, and so forth. Even the lower tier of transceivers are light years better in performance that what the average amateur radio operator used in the "goode olde dayes"! Then, the newcomer would appreciate the performance of "modern" equipment and the number of interference complaints would drop considerably.

    However, no one told us how bad our receivers actually were. So, we just had thousands of QSOs and, basically, "had a ball"!

    Glen, K9STH
    KE4OH likes this.

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