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  1. 9

    Reworking palomar 250

    Hi, I haven't posted here in a long time. In fact I've got my electronics tech degree since the last time I spoke. Some of you may remember my annoying biasing questions as I couldn't wrap my head around it. I know there has to be a thread with some info on what can be done to improve these...
  2. 9

    Non typical mosfet question

    Ok cool, Its difficult to express things through typing, I was really more or less looking for answer as to why it would do that, if it was the nature of the semiconductor, or antenna phenomenon. Is that what you're saying is, that you'd have to see what it did on the dummy load?
  3. 9

    Non typical mosfet question

    Ok, I have enough parts to wip up a dummy load w resistors. I may not be able to run it at full power, but I can get close. Once I do am I looking for it to match across the whole board or what ? Can u explain what I should look for?
  4. 9

    Non typical mosfet question

    Ya I'm not even really trying to get that much coverage, just cb plus a lil freeband. I just wanted to me sure I'm not adjusted incorrectly. At first I thought same as mobile cb a plied. Where if the lower channel was more power you adjust the antenna. Then I remembered the effects of those...
  5. 9

    Non typical mosfet question

    Hi everyone, it's been a whole since I posted. I have a couple questions about my base setup aND these mosfets everyone's using now. I'm using a magnum 257hp threw about 60 feet of very low loss thick coax I bought from a ham site (can't remember) into my sirio gain master mounted almost to...
  6. 9

    tuning dipole question

    Yea.. I'm afraid y'all are right. I'm not getting out. I want to so bad. With the horizontal antenna I'm picking up sine beautiful am on channel 11-15,17 and all sorts of things I never hear in the mobile. I'm not getting out at all.. if I drill a hole big enough through the roof for the coax...
  7. 9

    tuning dipole question

    Btw, it's a brick house. Roof it's just board & shingle. I made a few contact this weekend with poor conditions. The only thing that concerns me is a old exhaust fan... but the swr is low so... is it ok? I'm experiencing a few lost watts on the upper 5 but I can try and trim it back a lil.
  8. 9

    tuning dipole question

    Thanks for all the advice. I probably will end up putting it outside. I raised the end s and trimmed them back a little bit. The swr is 1:1.5. Weird thing is. On the "a band" it's doing 80 watts ssb and on "e band" it's doing like 60. Which is what it's suppose to do. Is this a watt meter...
  9. 9

    tuning dipole question

    Thanks for the replies. I've got the v shape at a perfect right angle. Just in the shape of an up side down v.. now.. conditions in my mobile have been HORRIBLE here all week so I'm not freaking out, but I'm not getting ANY signals at all. A couple very very faint.. seems odd an antenna that...
  10. 9

    tuning dipole question

    Hi everyone. I'm working on setting up my base. Magnum 257hp 50ft of bury flex going into the attic with a falcon dipole in inverted v config. I've got the power supply, bird, and scope all setup and is looking good. I've even got a arm boom stand and behringer condenser mic. My question...
  11. 9

    magnum 257 hp tx alignment

    Cool. I might check those fans out. It seem to me that this fans wouldn't make that big of difference
  12. 9

    magnum 257 hp tx alignment

    I just got this radio to set up my base. This is my first export. One thing I noticed is that the power is wide open on the low bands (band a) and low on j band. Do I need to tune it on the middle band? Or is this a typical compromise of these radios? I'm also running it into a salt water dummy...
  13. 9

    wide banding transmitters rx/tx

    When doing this typically which caps do I enlarge? Is 2.2uf really necessary, or can I just use 1uf? In this case in working on a galaxy. I know the .22uf going into the preamp but do I just follow the path to the audio chip? How about in the modulator and in the rx line?
  14. 9

    Biasing power transistors

    First attempt. I used "amplified diode current". It's where you use a resistor from v+ to the base of a Darlington and 2 series diodes cathode to gnd. Instead of grounding the emitter a capacitor is used. The emitter is then tied to the base of the rf transistors. I attempted to have it...
  15. 9

    Cobra 148 GTL driver bias help

    Hey 13, do you bias the final at 50/50 ma or 50/100? I can't get proper output at 50/50
  16. 9

    New cobra 148s

    Lol I agree! You'd think someone would step their game up and make one of these magnum route radios for cb. With all the digital ics and micro processors they could probably put most of the radio on o one chip! I don't get it either man..
  17. 9

    Cobra 148 GTL driver bias help

    That transistor may have gone bad. Do you have a replacement? If not check out weazle66 on eBay. Get 1 2sc2166 and one 2sc1969 might as well put a new final in it since you gotta order from England
  18. 9

    Cobra 148 GTL driver bias help

    Holy shit 650 ma.. did I read that right?? Driver 50ma final 100ma. Give me more details I'll try to help
  19. 9

    New cobra 148s

    I like to see how stable I can get it just for the hell of it and bc I got a massive amount of components, if I didn't I wouldn't. I actually have it performing pretty well. The only thumbs up I can give it is that it uses a regulator to bias the final.. that's pretty pimp, other than that.. :b
  20. 9

    Biasing power transistors

    I use pspice but I just found a bad ass one for android called everycircuit. There's a free trial but the whole version is worth it. You can change characteristics and values. And has 4 probes scope view