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Author Topic: Radio Shack HTX-242 Help  (Read 6663 times)
KE3WD
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Posts: 5694




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« Reply #15 on: December 30, 2012, 04:52:06 PM »

hi all I am in need of a little help I just received my tech Callsign and so I have am trying to get  ...the radio indicates that it is transmiting and my SWR meater says the radio is outputting power. 
Thanks,
Reg
KK4NJC

The sentence from the OP in first post, highlighted in bold here, would indicate that the Finals are operating. 

Something about internet forums, whenever someone's complaint is that they can't be heard, someone or three always has to mention the worst-case scenario of bad finals. 

There are a whole lot of OTHER things that can stop the show, though. 

FM two meter rig that keys up but can't be heard, first suspect is the MIC. 

The electret capsules inside the mic body of the 242's out there are rather notorious to this old bench technician as failing, often due to moisture getting thru the little hole and into the mic capsule. 

Replacement of the mic capsule is a lot cheaper and easier than finding another 242 Mic. 


73
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KE3WD
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« Reply #16 on: December 30, 2012, 04:55:32 PM »

hey quick question as if need be I will pickup a new rig but I am curious I put a dummy load ont he 242 and according to 2 SWR meters it is putting out full power but I get no voice would this be the Finals or could it be something betweent he mic jack and the transmitter? the reason I ask is I don't have the Original mic that came with it.

Thanks,
Reg
KK4NJC

Yes, it could be due to a bad mic capsule, or a broken connection either in the mic body or the connector at the rig, sometimes can happen somewhere in the middle of a mic cable that got pinched or stretched as well. 

The ohmmeter and a bit of time tracing continuity along the cable from inside the mic to the connector can pinpoint a broken connection. 

or, get a replacement mic.   if you can borrow a mic from someone who knows that the mic works on a 242, rather quick to plug it in and check for proper operation, then you know exactly what you need.


73
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YONU
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« Reply #17 on: December 30, 2012, 05:05:45 PM »

thanks guess I will go get the meter out  and unforutenitly I don't know anyone else with a HTX any Idea which pin on the pic connector is pin 1 so I can double check everything
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YONU
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Posts: 57




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« Reply #18 on: December 30, 2012, 07:17:31 PM »

well I found a Page with a good Diagram for the 242 and 212 mic so I figured I would post the link in the event it may help someone else out I will post after I test if the mic was the issue

http://mw0gkx.co.uk/micwiring/r/rs/rs12.htm
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K8AXW
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« Reply #19 on: December 30, 2012, 07:31:06 PM »

YONU:  Not the original mic......... hhhhhmmmmmmm  yeasssss.  That might be the problem!  A logical analysis and conclusion might be:  Dummy load, full output....no audio.  First thing to check is the mic cord..... but in your case the first thing to check would be the mic....since it's an aftermarket mic....especially check to see if it's wired up properly. 

If it's wired up properly then the next thing I'd do is to try another mic.  Somehow....

Whenever you post a question YONO, please include ALL information..... rig, power output, SWR, power supply voltage if powered by an external supply and all the gear you have hanging on the rig. 

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YONU
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« Reply #20 on: December 30, 2012, 07:36:21 PM »

well I had tested the mic but after lookign at the Diagram I linked I think the mic I had was wired wrong so I will be rewiring it and trying it on the 242 again

and sorry got not following proper posting
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KA4POL
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Posts: 1913




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« Reply #21 on: December 30, 2012, 11:22:47 PM »

Ah, measuring is always better than guessing. Full power, if correctly measured, means the final transistor is fine.
No modulation could well be the case, especially if you changed the mic. Just try to touch the mic input of your rig using a short piece of wire. This should result in the well known 60 Hz hum to be heard in a receiver.
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K1CJS
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« Reply #22 on: December 31, 2012, 10:30:45 AM »

hey quick question as if need be I will pickup a new rig but I am curious I put a dummy load ont he 242 and according to 2 SWR meters it is putting out full power but I get no voice would this be the Finals or could it be something betweent he mic jack and the transmitter? the reason I ask is I don't have the Original mic that came with it.

You didn't indicate that the mike wasn't the one supplied with the radio.  It may be possible the mike you've got was just put with the radio to say the radio had a mike with it, and that mike is the wrong impedance or isn't wired properly.  It may be well worth it to get a replacement mike and try it.  The place where the mike cord conductors would break most often is right at the modular plug that connects to the rig itself--you may want to look at the first. 

As much as it pains me to say it, look on e-Bay and see what you can come up with for a replacement mike, and do that first.  The finals may well be OK.
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YONU
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Posts: 57




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« Reply #23 on: December 31, 2012, 05:03:07 PM »

Well good news and bad news I had ordered a mic from packetradio that was suppose to be compatible well the mock part is so I am happy and I was able to transmit to a reciever up the road however it isn't breaking squelch according to a local ham they said they just could hear me. Could that be antenna related? Or is it rig related
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K8AXW
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« Reply #24 on: December 31, 2012, 07:19:45 PM »

YONU:  Sound like you're on the right track.  Once again, make sure the mic is wired properly with good solder connections and if the problem is still there I would immmediately suspect that the mic is the wrong impedance. 

Ya wanna guess how many times I've heard the statement(s), "It will work with that rig.....it's the same as..... it's a substitute for..... Huh"

Don't bleeve nuthin ya heer!
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YONU
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« Reply #25 on: December 31, 2012, 07:24:00 PM »

ok cool thanks now for one more question if it the wrong impedance can I simply change the mic element to one of the proper impedance or is there more to it than that?

Thanks,
Yonu
KK4NJC
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KE3WD
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Posts: 5694




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« Reply #26 on: January 01, 2013, 06:44:05 AM »

ok cool thanks now for one more question if it the wrong impedance can I simply change the mic element to one of the proper impedance or is there more to it than that?

Thanks,
Yonu
KK4NJC

'242 was designed to use an electret condenser mic element. 

Does the aftermarket mic you purchased use electret condenser? 

Easy clue is that there will be one tiny hole exposing the business end of an electret. 

Electret elements are inexpensive and rather easy to replace, two, sometimes three solder joints. 


73
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K1CJS
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« Reply #27 on: January 01, 2013, 07:50:40 AM »

...according to a local ham they said they just could hear me....

Could still be anything.  Now that you've got the mike issue straightened out, check the wiring from the antenna connection to the antenna itself.  Use an ohmmeter.  Could be that you've got an open in the co-ax somewhere, or even a short.  Pay particular attention to the ends of the co-ax, especially at the transceiver end--the cable to the PL-259.  And don't discount the possibility that the radio itself may have a fault.  For instance, the solder connections to the SO-239 may have broken, or may be just insufficiently soldered.  Some runs of certain Radio Shack products are famous for that.

You didn't say whether the antenna was inside or outside.  It will work better outside.  Does your dipole have elements a little over 19 inches on either side?  Longer or shorter elements will throw the SWR off and cause the range to be decreased.  Is the dipole mounted vertically or horizontally?  For 2 meter FM (the mode you're using) it should be mounted vertically.  That one thing could be causing the problem.

There are a lot of things that could be affecting your ability to get your signal out.  Get a ham radio handbook if you don't have one and do some reading--it will do you more good than just asking questions here on e-ham, for the simple reason that none of us could cover every possibility that may exist in solving the problem you have.  There are simply too many possibilities--and the solution may be something you and everyone else has overlooked.  73!
« Last Edit: January 01, 2013, 08:03:03 AM by K1CJS » Logged
YONU
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Posts: 57




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« Reply #28 on: January 01, 2013, 10:13:11 AM »

ok I will pick one up and have a read

to awnser your question the antenna is outside 25ft in the air I am getting a 2:1(hope I wrote that right) ont he SWR I get a 1:1 on a dummy load but I will check the so-239 pigtail coming from the radio and I may change it anyway just as I don't like the looks of it.

It is a vertical Dipole now due to space the antennal is mounted about 5ftbeside 10ftover the incoming service cable from the power company yes I know a safety nono but could that actually cause enough interference to drown out the signal?.

Thanks,
Yonu
KK4NJC
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K7KBN
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Posts: 2764




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« Reply #29 on: January 01, 2013, 01:19:53 PM »

ok I will pick one up and have a read

to awnser your question the antenna is outside 25ft in the air I am getting a 2:1(hope I wrote that right) ont he SWR I get a 1:1 on a dummy load but I will check the so-239 pigtail coming from the radio and I may change it anyway just as I don't like the looks of it.

It is a vertical Dipole now due to space the antennal is mounted about 5ftbeside 10ftover the incoming service cable from the power company yes I know a safety nono but could that actually cause enough interference to drown out the signal?.
Thanks,
Yonu
KK4NJC


There's no way we can tell from where we are.  The only one who can answer that is you.  It might - but it might not.
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73
Pat K7KBN
CWO4 USNR Ret.
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