Re: Ozark Patrol build problem


Jim Kortge
 

On 10/5/2014 10:41 AM, David Wilcox @K8WPE [4sqrp] wrote:


Guys and Gals,
I just finished the Ozark Patrol and it went together easily, but
can't get consistent regeneration. From the get go the regen pot
sounded like an old pot on an old radio that was dirty (scratchy). I
have cleaned it twice with CRC contact cleaner and no change. If you
don't think that is the problem what else could it be? I haven't
checked the voltages yet per the trouble shooting guide ( my batteries
are new and measure 9.4 volts ) but this "dirty pot sound" was so
obvious. I really hesitate to blame the pot but I can't get an even
variable regeneration with what I have. Any advice?
It is the pot, but it can't be fixed with CRC cleaner or anything of the like. The issue is that small changes in pot noise for movement are getting amplified by the reflex circuits and makes the pot sound really noisy. I solved it by adding a 1uF tantalum cap from the higher voltage terminal of the pot to the center wiper terminal and all of the noise went away. I reported that phenomenon to the 4 State gang but I guess that observation got lost.

I could hear a
few very weak stations speaking Spanish around 9 mHz.
Second problem. When I plug in a pair of headphones (Walkman style or
my good Sony studio head set) I get nothing unless I ground #4 on the
jack pin with a jumper. There is a tab (looks like a grounding tab)
where the jack is fastened to the board with no wire attached. I
assume that is grounded by pressure to the board and needs no wire.
What are your thoughts?
I don't remember any issues with the jack mounting when my receiver was built, only the wiring of the transformer to the jack that would not switch off the speaker and connect the phones.


I'm not sure how your headphones are wired, but the ones that I used were find, BUT, the is an error in the wiring of the output transformer secondary to the jack. I also reported that on the unit that I built but I guess that piece of information was also overlooked.

Audio seems down on the speaker.
When you get on a strong station there will be plenty of audio for the speaker, but phones work a lot better when the jack wiring is corrected. I'm hoping 4 State will publish an online addendum for the manual.

I questioned the output transformer
installation but the "P" side is connected to the board as per
instructions. Anyone found the red tape with the "P" label on it
backwards from the factory?
The transformer is OK.

I am using my MFJ G5 RV antenna that is my main shack antenna and a
good shack ground.
Dave K8WPE
For what it is worth, I also replaced both of the gimmic capacitors with 4.7 pF ceramic NP0 units and the receiver was much better and selectivity and audio output. I thought that change was also going to be made to the kit.

72,

Jim, K8IQY

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