Re: [BayouJumper] Spotting problem


David Martin <davemrtn@...>
 

Also, Front Panel on or off does have a considerable effect on the tuning frequency of the receiver.

I have worked on mine to the point I can spot my crystal frequency with acceptable accuracy, but only with the front panel removed.

Spotting with the front panel in place moves the receive frequency up about 10KHz (by spotting) according to testing using another radio as the signal source after spotting.

I am using another radio as a signal source to determine where the receive frequency is after spotting for both conditions of Front Panel Mounting.

I thought about the possibility of the front panel being mounted causing some unusual coupling back into the audio amplifier.  The collector of Q3 has a fairly large capacitor, C24, to decouple any RF there.

I tried putting a 220pF cap in the feedback loop of U1 (pins 4 to 5) and that didn't help.

Anybody got any ideas ??

I am baffled as to why the front panel being mounted would cause the Rx Spotting frequency to be high by 10KHZ !!! ???

NA1MH


On 1/9/2017 14:01, David Martin davemrtn@... [4sqrp] wrote:
 

I have been experimenting with mine today.

First thing I did was change R17, in the Tx circuit, from 1K to 6.8K in an attempt to lower the output of the spotting signal, assuming the R17 & D1  were still allowing Q4 to contribute to the spotting signal.

That seemed to help me since my Bayou Jumper was all over the dial (end to end) when trying to 'Spot'.

While turning the tuning control in the 'Spot' mode, my tuning control sounds very 'scratchy', but not while in normal receive mode.

I noticed on the receiver schematic the audio output from Q3 was going through a C9 to the wiper on the volume control.  My personal preference is NOT to do it that way.  So I changed that circuit so C9 feeds the high side of the volume control and the wiper feeds C13 going to the IC audio amp.

Now with Regen at minimum, Atten at maximum and Volume at a comfortable level (just barely turned up), I can spot the signal (somewhat), but the tuning control still sounds scratchy.

I say I am spotting the signal, let me explain...
I am using my FT-817 to to determine what is what.
With the Bayou Jumper key down for spotting, I can "spot" the signal on the Bayou Jumper, and the FT-817 says the transmit frequency is approx 7.29MHz (using the 7030 crystal).

Releasing the Bayou Jumper key, I then tune the FT-817 to see where the regen oscillator is.  No matter what I do the Regen oscillator always comes out about 20KHz higher than the Crystal frequency.
I would expect the regen freq to not be dead on the crystal frequency, but not off by 20KHz.

What am I missing here ??

NA1MH



On 1/9/2017 12:31, Rick Nelson laseraddict777@... [BayouJumper] wrote:
 
I'm having the same problem here. It seemed that I initially had the two heterodynes as described-- without doing any regen.  trimmer- cap c30 or tuner- coil winding adjustments-- but then-- for some unknown reason, after putting the front panel on, I lost this SPOTTING capability and could only tune in my own signal ( in receive position) listening to "tuning little beeps" to settle in on the Xtal frequency. The nice solid, twin heterodynes on either side of my signal HAD DISAPPEARED and I could not get them back! :(

I am getting close to resigning myself to marking the dial according to where another Xmtr shows my 7.030 frequency to be on the BJ-1.

Any further suggestions from anybody will be appreciated. I like things to work the way they should-- my downfall!

73's/72's from Rick, W B 3 B I Q

Sent from my iPad

On Jan 8, 2017, at 2:08 PM, deadgoose@... [BayouJumper] <BayouJumper@...> wrote:

 

Is there a way to tame down the spotting issue? 


Even with full attenuation and regeneration cut entirely down, it is still difficult to spot you crystals. I have ended up -- not at all convenient -- hooking up my Yaesu VR-500 "DC to Daylight" radio and setting it to my crystal frequency, then setting regeneration up and adjusting the dial to hit the setting of the radio. I've marked the points on the dial with dots of yellow paint, but re-setting to a value seems to be problematic.


Any suggestions?


Success will depend on somebody answering my CQ and being willing to be a tad off. I have had people take me to task when using my KN-Q7A SSB rig, which has a VXO, and not being able to exactly come on frequency. They don't seem to know about using an RIT....


73 /paul W3FIS


-- 
David Martin - NA1MH - Mountain Home, Ar.
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-- 
David Martin - NA1MH - Mountain Home, Ar.
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