Re: No hiss from speaker

David Wilcox

Will have to teach an 11 year old how to tune it differently now.  There are 3 loud stations in Marion, Indiana but I am trying to show him how to tune for weaker stations after dark.  I wonder how many young folks don’t have a “radio” in their home.?  My grand son has never seen one other than the car radio and doesn’t even know how to use that as his family uses XM radio in their car or blue tooths from their iPhone.

Does turning down the sensitivity really work at night for distant stations?  I will have to try it.  I have a 5000 w station at 1310 khz about 2 miles across the lake from me.  It kills my favorite 75 meter net on 3930 khz.

David J. Wilcox K8WPE’s iPad

On Nov 27, 2018, at 10:11 AM, Jim WB2LHP in MI <jmarco1955@...> wrote:

GM Dave...The original circuit worked well if you were not in the presence of strong stations...I have 50kW and 15kW stations in my back yard so I'm completely swamped with RF here...When you say you would like the LED to work as intended, I'm assuming you mean using it as a tuning indicator as described in the manual...The LED is used as a voltage regulator/power indicator...The dip in brightness was a result of the TA7642 being overloaded...You won't see that now...Tuning by ear will work fine for you...Tuning now is a two-handed operation, controlling gain and frequency as you move around the dial but your grandson should have no problem with that...It actually makes finding stations more fun, especially at night...Increasing the L1 coil turns from 37 to 61 and removing C9 should fix your tuning range...

The Murania is a GREAT radio...It's both my favorite and my go-to AM broadcast receiver...Dave and the 4SQRP team did a fabulous job with this kit...GL with your final changes and let me know if you have any questions...73 Jim WB2LHP

On Tue, Nov 27, 2018 at 4:57 AM David Wilcox via Groups.Io <> wrote:
I did the mods and the audio is much better, but what was the original problem with the radio if some had good results building it as instructed?  I would still like the LED to work as intended.  I took the rig home to fix the terrible audio and will mail it back to 11 y/o grand son.  Will have to write a new instruction manual as the audio is now wide open and he will have to learn to use the audio control as a RF control.

I am next going to add the turns on the coil as a strong station at 1310 khz wipes out the rest of the dial and there is a station at 1400 khz that I want to hear.

Did the beta builders have any trouble with performance?  Our original build sounded terrible. 

David J. Wilcox K8WPE’s iPad

On Nov 23, 2018, at 2:40 PM, Jim WB2LHP in MI <jmarco1955@...> wrote:

Hi Dave...My two resistor mods will absolutely improve the performance of the Murania...The Changes to L1 and C9 are NOT necessary unless you're fussy like me about the frequency coverage...

Let me know if you have any questions about the mods but everyone so far that has used them have had great results with them...73 Jim WB2LHP

P.S. The Murania is my go-to AM radio, especially for late night DX'ing...It plays beautifully...

On Fri, Nov 23, 2018 at 2:30 PM David Wilcox via Groups.Io <> wrote:
 My 11 year old grandson and I had the same issue, no hiss and no hum. We finished the kit and it did work, however there’s a sufficient amount of audio distortion on the stronger stations. I’m going to try some of the listed mods next to see if we can get a bit less distortion  and make it a little easier on the ears.

 We could hear three strong stations here in Marion, Indiana. 

 What a fun kit. I pre-built the case and the antenna coil as that might’ve been a little too much for an 11-year-old. He is now getting confident enough to hold both the soldering iron and the solder. In the past I would hold the soldering iron and he would apply the solder.  He is learning how to identify the parts and hands them to me at the appropriate time. We test each resistor on an ohm meter. He can see the small numbers on the capacitors with his naked eyes. I still need the magnification and light from my loupe. 

Dave K8WPE

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