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   Home   Help Search  
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Author Topic: troubleshooting a Penetrater HB-200  (Read 7355 times)
W7JTC
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Posts: 7




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« on: November 17, 2004, 07:43:27 PM »

Just got this thing today and was testing it on 10 meters. @ 4 watts in, was giving 100 watts out. @ 10 watts in, 200 watts out. I switched to a new frequency several mhz away. The amp clicked on when I keyed the mic, but no RF out. Have checked everything inside by eye, I see no obvious problems. The relay still clicks, just no RF gets out. Have tried a few different radios, etc. No change. Could this thing have a SWR protection circuit or something obvious? This is my first amp. Came with no instructions, schematics, etc. Help, I'm lost! KD7EKG
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W7DJM
Member

Posts: 1




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« Reply #1 on: November 17, 2004, 10:35:14 PM »

Do yourself a big huge favor.  Tear this thing apart and use it to learn something.  Do NOT be tempted to put it on the air.

This is an illegal CB amp, plain and simple.  None of these have bandpass filters, and are generally very dirty--the spectral output, that is.
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K7KBN
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Posts: 3693




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« Reply #2 on: November 18, 2004, 07:01:43 AM »

An Extra should know that....
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73
Pat K7KBN
CWO4 USNR Ret.
W7DJM
Member

Posts: 1




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« Reply #3 on: November 18, 2004, 09:03:04 AM »

You're a "former member of Mensa" and that's the best answer you could think up?
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WB2WIK
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Posts: 21837




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« Reply #4 on: November 18, 2004, 10:06:51 AM »

That surely is a non-certificated amplifier.

But you didn't say what the new frequency was where you tried it, and it didn't work.  "Several MHz away" could be anywhere.  What frequency?

Since this is a "CB" amp, it's likely optimized for 27 MHz and may not work too far from that part of the spectrum.  These "low drive" amps are almost always problematical and not a good choice for amateur work unless highly modified with bias circuits to improve linearity and filtering to improve purity.  And, unless the amp's only used on 10M and not lower frequencies, a bandswitch to change filters and assure purity band-to-band.  A 30 MHz LPF doesn't do anything to make the amp legal on, say, 20 meters where the second harmonic would fall within the filter's passband.

WB2WIK/6
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K7KBN
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Posts: 3693




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« Reply #5 on: November 18, 2004, 12:50:41 PM »

Am I incorrect in stating that an Extra should know at least this much about amplifiers?
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73
Pat K7KBN
CWO4 USNR Ret.
W7JTC
Member

Posts: 7




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« Reply #6 on: November 19, 2004, 02:03:51 PM »

Wow. Thanks. To some of you. To the one who says I should know better because I'm an extra... where do you get off? I am aware this is a cheap amplifier and the plan was to learn something by taking it apart, as suggested by W7DJM. I have learned what I can from it and need help with the rest. Correct me if I'm wrong, this is a forum where people seek help, right? And the help is given voluntarily, right? And isn't this a "community" hobby where this help is gladly given? Look, I'm already pulling my hair out over this amp trying to learn so I CAN "know better". K7KBN, all your posts have done is raise my hopes that some kind soul has posted something helpful. Thanks for nothing.
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KI4DJN
Member

Posts: 6


WWW

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« Reply #7 on: November 20, 2004, 09:57:45 PM »

K7KBN

No!
He is an extra he may be learning like the rest of us, it is a hobby and we all have differing knowledge bases. Are you computer proficient, aren't you are using one?
Back off and have some fun! . Pontificating gets you no where
I'm a tech but I bet I have forgotten more about computers and networking them than you know.
Keep asking questions, KD7EKG, that is a great way to learn.
73 Stu
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KE3HO
Member

Posts: 235




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« Reply #8 on: November 22, 2004, 10:26:37 AM »

If this is a learning project, I have been down this road before. Typically these amplifier have receive pre-amps and they have more than one relay - one to switch the power amplifier in/out and another to switch the pre-amp in/out. The one that switches the pre-amp will operate with any RF input over a broad frequency range. You don't want the receive pre-amp to have several watts of RF blasted into its output. The second relay that operates the power amplifier section often has a filter section in the relay drive circuit so it only operates above about 28 MHz or so. They do this to claim that it "won't operate" on the CB band (although this does nothing to make the amplifier legal for commercial sale in the US - don't know about other countries). To get these into their "target" market - illegal CB usage - they will often have a jumper on the board for "test" purposes that will switch the power amp relay on/off with any RF on the input just like the pre-amp section. The relay switching that you hear on the non-10M frequency may just be the pre-amp relay operating, not the PA relay.

As stated by others, don't trust this thing to be linear or spectrally clean. Use it as a starting point for a homebrew amp, just make sure you add the appropriate filtering, proper biasing, etc.

Good Luck and 73
Jim
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W7JTC
Member

Posts: 7




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« Reply #9 on: November 22, 2004, 11:36:58 AM »

So if I fed it a bad SWR accidentally or too much RF input (maybe 10 watts) what could I have blown? Because I can still hear the relay switching, but get no RF out. Thanks for all your help!
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K8DO
Member

Posts: 5




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« Reply #10 on: November 22, 2004, 11:46:49 AM »

Which tubes?  If sweep tubes, the ten watts of drive may have been too much... The old Hunter Bandits (one step removed from the chicken band)would munch a set of sweep tubes in two  heart beats if overdriven, or off resonance...

Denny - K8DO
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