Topics

Another mod to the Bayou Jumper


Jim Sheldon
 

I had a 1.5" diameter Philmore vernier dial laying around so I decided to see how difficult it would be to install for tuning the Bayou Jumper which is sort of fast and difficult, but not impossible, to get just right. 
 
First, it was necessary to drill out the hole in the panel for the tuning pot to a diameter of 7/16" to allow for clearance of the shaft coupler on the vernier.  Next, it was necessary to cut the tuning pot shaft down to just over 1/4" long and the bottom of the shaft coupler still bottomed out on the frame of the pot, leaving the base of the vernier mechanism about 1/8" above the panel.  There are two options here, grind down the shaft coupler until the vernier sits flush with the panel and the coupler doesn't bind on the frame of the pot or use 1/8" or so of spacers between the panel mounting standoffs and the panel (easier at assembly time to add the spacers between the main PC board and the bottom of the standoffs).  The mounting holes for the vernier must be carefully laid out and drilled for 2-56 screws and 2 of these are used to mount it to the panel.
 
Before re-assembling the panel/pc board combination, set the shaft on the tuning pot to mid range and the vernier to midrange (#50).  Carefully fit everything into place, tighten all the panel mounting screws and other top side hardware just like you did on the initial assembly.  Next, very carefully tighten the set screw on the vernier's shaft coupler to lock it to the tuning shaft of the pot.  You will only have 180 degrees of rotation rather than the full 270 degrees but this should fall within the 7020 to 7130 range assuming you had done the calibration steps earlier.
 
I used the 1.5" Philmore S38 vernier.  The S50 is a 2" diameter dial and these are also available for somewhere around the same price or just a little more.  The S38 is the ideal one as it fits within all original markings on the Bayou Jumper's panel where the S50 will cover the word Tuning and the top will extend into, if not completely cover the original V shaped pointer at top center. 
 
It's a daunting modification and probably most won't do it, but it does really slow down the tuning and makes it much easier to tune in a CW station and it's now actually possible to also tune in the SSB stations at the high end if they fall within the tuning range.  The radio is quite stable and once tuned to a frequency I didn't observe any drift after a couple minutes of warm up.  Super job by the designers.
 
Jim - W0EB
 
 
It actually looks pretty decent mounted on the radio - helps a lot with ease of tuning in a signal.
 
 
Closer picture of the installed Philmore S38 vernier dial


keith ford
 

On Thursday, January 5, 2017, 18:49, 'Jim Sheldon' w0eb@... [4sqrp] <4sqrp@...> wrote:

 

I had a 1.5" diameter Philmore vernier dial laying around so I decided to see how difficult it would be to install for tuning the Bayou Jumper which is sort of fast and difficult, but not impossible, to get just right. 
 
First, it was necessary to drill out the hole in the panel for the tuning pot to a diameter of 7/16" to allow for clearance of the shaft coupler on the vernier.  Next, it was necessary to cut the tuning pot shaft down to just over 1/4" long and the bottom of the shaft coupler still bottomed out on the frame of the pot, leaving the base of the vernier mechanism about 1/8" above the panel.  There are two options here, grind down the shaft coupler until the vernier sits flush with the panel and the coupler doesn't bind on the frame of the pot or use 1/8" or so of spacers between the panel mounting standoffs and the panel (easier at assembly time to add the spacers between the main PC board and the bottom of the standoffs).  The mounting holes for the vernier must be carefully laid out and drilled for 2-56 screws and 2 of these are used to mount it to the panel.
 
Before re-assembling the panel/pc board combination, set the shaft on the tuning pot to mid range and the vernier to midrange (#50).  Carefully fit everything into place, tighten all the panel mounting screws and other top side hardware just like you did on the initial assembly.  Next, very carefully tighten the set screw on the vernier's shaft coupler to lock it to the tuning shaft of the pot.  You will only have 180 degrees of rotation rather than the full 270 degrees but this should fall within the 7020 to 7130 range assuming you had done the calibration steps earlier.
 
I used the 1.5" Philmore S38 vernier.  The S50 is a 2" diameter dial and these are also available for somewhere around the same price or just a little more.  The S38 is the ideal one as it fits within all original markings on the Bayou Jumper's panel where the S50 will cover the word Tuning and the top will extend into, if not completely cover the original V shaped pointer at top center. 
 
It's a daunting modification and probably most won't do it, but it does really slow down the tuning and makes it much easier to tune in a CW station and it's now actually possible to also tune in the SSB stations at the high end if they fall within the tuning range.  The radio is quite stable and once tuned to a frequency I didn't observe any drift after a couple minutes of warm up.  Super job by the designers.
 
Jim - W0EB
 
 
It actually looks pretty decent mounted on the radio - helps a lot with ease of tuning in a signal.
 
 
Closer picture of the installed Philmore S38 vernier dial


Dick Hammond
 

Great job Jim and looks real professional.

Dick,  n0tgr

On Thu, Jan 5, 2017 at 6:49 PM, 'Jim Sheldon' w0eb@... [4sqrp] <4sqrp@...> wrote:
 

I had a 1.5" diameter Philmore vernier dial laying around so I decided to see how difficult it would be to install for tuning the Bayou Jumper which is sort of fast and difficult, but not impossible, to get just right. 
 
First, it was necessary to drill out the hole in the panel for the tuning pot to a diameter of 7/16" to allow for clearance of the shaft coupler on the vernier.  Next, it was necessary to cut the tuning pot shaft down to just over 1/4" long and the bottom of the shaft coupler still bottomed out on the frame of the pot, leaving the base of the vernier mechanism about 1/8" above the panel.  There are two options here, grind down the shaft coupler until the vernier sits flush with the panel and the coupler doesn't bind on the frame of the pot or use 1/8" or so of spacers between the panel mounting standoffs and the panel (easier at assembly time to add the spacers between the main PC board and the bottom of the standoffs).  The mounting holes for the vernier must be carefully laid out and drilled for 2-56 screws and 2 of these are used to mount it to the panel.
 
Before re-assembling the panel/pc board combination, set the shaft on the tuning pot to mid range and the vernier to midrange (#50).  Carefully fit everything into place, tighten all the panel mounting screws and other top side hardware just like you did on the initial assembly.  Next, very carefully tighten the set screw on the vernier's shaft coupler to lock it to the tuning shaft of the pot.  You will only have 180 degrees of rotation rather than the full 270 degrees but this should fall within the 7020 to 7130 range assuming you had done the calibration steps earlier.
 
I used the 1.5" Philmore S38 vernier.  The S50 is a 2" diameter dial and these are also available for somewhere around the same price or just a little more.  The S38 is the ideal one as it fits within all original markings on the Bayou Jumper's panel where the S50 will cover the word Tuning and the top will extend into, if not completely cover the original V shaped pointer at top center. 
 
It's a daunting modification and probably most won't do it, but it does really slow down the tuning and makes it much easier to tune in a CW station and it's now actually possible to also tune in the SSB stations at the high end if they fall within the tuning range.  The radio is quite stable and once tuned to a frequency I didn't observe any drift after a couple minutes of warm up.  Super job by the designers.
 
Jim - W0EB
 
 
It actually looks pretty decent mounted on the radio - helps a lot with ease of tuning in a signal.
 
 
Closer picture of the installed Philmore S38 vernier dial



Jim Sheldon
 

Thanks Dick,

It actually works as good as it looks.  I have some of the 2" S50's on order, but I'm glad I used this one. The 2" S50's will fit but probably look out of place as they WILL cover up some original panel markings.  All the original markings on the panel are intact and the little dial actually looks like it belongs on the radio.  Sure helps with ease of tuning too.

The mod isn't the easiest and probably not for the faint of heart, but it can be done.  Worth it or not?  I guess that's up to the individual.  Personally it really enhances my enjoyment of the little rig and I'm glad I took the chance and did it.

Jim, W0EB

Sent from my iPad

On Jan 5, 2017, at 7:37 PM, Dick Hammond <n0tgr2@...> wrote:

Great job Jim and looks real professional.

Dick,  n0tgr

On Thu, Jan 5, 2017 at 6:49 PM, 'Jim Sheldon' w0eb@... [4sqrp] <4sqrp@...> wrote:
 

I had a 1.5" diameter Philmore vernier dial laying around so I decided to see how difficult it would be to install for tuning the Bayou Jumper which is sort of fast and difficult, but not impossible, to get just right. 
 
First, it was necessary to drill out the hole in the panel for the tuning pot to a diameter of 7/16" to allow for clearance of the shaft coupler on the vernier.  Next, it was necessary to cut the tuning pot shaft down to just over 1/4" long and the bottom of the shaft coupler still bottomed out on the frame of the pot, leaving the base of the vernier mechanism about 1/8" above the panel.  There are two options here, grind down the shaft coupler until the vernier sits flush with the panel and the coupler doesn't bind on the frame of the pot or use 1/8" or so of spacers between the panel mounting standoffs and the panel (easier at assembly time to add the spacers between the main PC board and the bottom of the standoffs).  The mounting holes for the vernier must be carefully laid out and drilled for 2-56 screws and 2 of these are used to mount it to the panel.
 
Before re-assembling the panel/pc board combination, set the shaft on the tuning pot to mid range and the vernier to midrange (#50).  Carefully fit everything into place, tighten all the panel mounting screws and other top side hardware just like you did on the initial assembly.  Next, very carefully tighten the set screw on the vernier's shaft coupler to lock it to the tuning shaft of the pot.  You will only have 180 degrees of rotation rather than the full 270 degrees but this should fall within the 7020 to 7130 range assuming you had done the calibration steps earlier.
 
I used the 1.5" Philmore S38 vernier.  The S50 is a 2" diameter dial and these are also available for somewhere around the same price or just a little more.  The S38 is the ideal one as it fits within all original markings on the Bayou Jumper's panel where the S50 will cover the word Tuning and the top will extend into, if not completely cover the original V shaped pointer at top center. 
 
It's a daunting modification and probably most won't do it, but it does really slow down the tuning and makes it much easier to tune in a CW station and it's now actually possible to also tune in the SSB stations at the high end if they fall within the tuning range.  The radio is quite stable and once tuned to a frequency I didn't observe any drift after a couple minutes of warm up.  Super job by the designers.
 
Jim - W0EB
 
 
It actually looks pretty decent mounted on the radio - helps a lot with ease of tuning in a signal.
 
 
Closer picture of the installed Philmore S38 vernier dial



Jim, N5IB
 

Check out this part from Marlin P Jones

http://www.mpja.com/10K-Ohm-10-Turn-Variable-Resistor-with-Dial/productinfo/32676+VR/

http://www.mpja.com/download/32676VRMech.pdf

It's a ten-turn 10K pot with a "clock face" dial. $6.95
To use it as a replacement for R8, just change R5 to either 6.2K or 6.8K
The fact that it's a wirewound pot is not an issue, as there is only DC on R8.

The problem is that it projects a bit over 1" above its mounting surface, so some pretty good surgery would be needed to the panel to allow the box lid to close and latch. It would have to be recessed into the panel by 3/8" or so.

N5IB


keith ford
 

Wow! I want one! 

On Thursday, January 5, 2017, 20:13, n5ib@... [4sqrp] <4sqrp@...> wrote:

 

Check out this part from Marlin P Jones

http://www.mpja.com/10K-Ohm-10-Turn-Variable-Resistor-with-Dial/productinfo/32676+VR/

http://www.mpja.com/download/32676VRMech.pdf

It's a ten-turn 10K pot with a "clock face" dial. $6.95
To use it as a replacement for R8, just change R5 to either 6.2K or 6.8K
The fact that it's a wirewound pot is not an issue, as there is only DC on R8.

The problem is that it projects a bit over 1" above its mounting surface, so some pretty good surgery would be needed to the panel to allow the box lid to close and latch. It would have to be recessed into the panel by 3/8" or so.

N5IB


Jim Sheldon
 

Hey Jim, I think it will fit.  I just checked the data sheet and from the mounting surface to the top of the dome is 24.5 mm.  That's about a half mm under an inch.  I just stacked a couple of bug weights on top of each other and the height came out to just about a mm over an inch.  The lid of my box will close completely without hitting the top weight on the stack.  I measured it real carefuly with a 6" steel rule that has both mm and inch scales on it. 
 
There should be plenty of room on the underside to do whatever is necessary to make it fit once you remove the original tuning pot and you won't have to cut any traces to do the tuning direction mod.  I didn't anyway, I just didn't solder the two outer terminals on the pot.  I bent them out and soldered cross-over wires from them to the appropriate holes on the board.  Much easier than cutting traces and easily restored to original condition if necessary.
 
I may have to see if I can buy another front panel as I have 3 mounting holes drilled for the vernier in mine now and a new panel would certainly make it look better.
 
I just ordered a couple of those pots from MPJA.  I am a regular customer of theirs. I buy all my normal QRP travel cases from them (the yellow Pelican knock-offs that are about 1/2 or less than Pelican wants for them and they really work nice.
 
Jim - W0EB
 

Check out this part from Marlin P Jones

http://www.mpja.com/10K-Ohm-10-Turn-Variable-Resistor-with-Dial/productinfo/32676+VR/

http://www.mpja.com/download/32676VRMech.pdf

It's a ten-turn 10K pot with a "clock face" dial. $6.95
To use it as a replacement for R8, just change R5 to either 6.2K or 6.8K
The fact that it's a wirewound pot is not an issue, as there is only DC on R8.

The problem is that it projects a bit over 1" above its mounting surface, so some pretty good surgery would be needed to the panel to allow the box lid to close and latch. It would have to be recessed into the panel by 3/8" or so.

N5IB


Curt
 

Jim,

You do beautiful work, with the vernier the Jumper looks even more "retro" than the unmodified one.  You have much more courage than I doing such a modification.  I have no difficulty tuning mine, it is amazingly stable for a regenerative radio.  Enjoy this radio a lot, and the wide tuning range is part of the enjoyment.  Yesterday listened to an SSB QSO on 7150.

I need to figure out how to package my "prototype" built with PCB from N5IB.  It is paired with a 2fer which incorporates a variable cap to bend the crystal frequency a little.

72, Curt KB5JO


random.path
 

Hi Jim -

I'm trying the vernier dial mod to my BJ. To get an extra 1/8" of clearance for the shaft, I used 3/4" standoffs instead of the 5/8" standoffs. The work to let the vernier shaft just clear the pot, but now all of the other pot shafts are too short to be engaged by the supplied knobs.

Grinding the vernier shaft down would work, but to get 1/8" it looks like he set screw hole will be compromised.

What did you find on your build?

Thanks,
Chip
AE5KA

On Thu, Jan 5, 2017 at 7:49 PM, 'Jim Sheldon' w0eb@... [4sqrp] <4sqrp@...> wrote:
 

I had a 1.5" diameter Philmore vernier dial laying around so I decided to see how difficult it would be to install for tuning the Bayou Jumper which is sort of fast and difficult, but not impossible, to get just right. 
 
First, it was necessary to drill out the hole in the panel for the tuning pot to a diameter of 7/16" to allow for clearance of the shaft coupler on the vernier.  Next, it was necessary to cut the tuning pot shaft down to just over 1/4" long and the bottom of the shaft coupler still bottomed out on the frame of the pot, leaving the base of the vernier mechanism about 1/8" above the panel.  There are two options here, grind down the shaft coupler until the vernier sits flush with the panel and the coupler doesn't bind on the frame of the pot or use 1/8" or so of spacers between the panel mounting standoffs and the panel (easier at assembly time to add the spacers between the main PC board and the bottom of the standoffs).  The mounting holes for the vernier must be carefully laid out and drilled for 2-56 screws and 2 of these are used to mount it to the panel.
 
Before re-assembling the panel/pc board combination, set the shaft on the tuning pot to mid range and the vernier to midrange (#50).  Carefully fit everything into place, tighten all the panel mounting screws and other top side hardware just like you did on the initial assembly.  Next, very carefully tighten the set screw on the vernier's shaft coupler to lock it to the tuning shaft of the pot.  You will only have 180 degrees of rotation rather than the full 270 degrees but this should fall within the 7020 to 7130 range assuming you had done the calibration steps earlier.
 
I used the 1.5" Philmore S38 vernier.  The S50 is a 2" diameter dial and these are also available for somewhere around the same price or just a little more.  The S38 is the ideal one as it fits within all original markings on the Bayou Jumper's panel where the S50 will cover the word Tuning and the top will extend into, if not completely cover the original V shaped pointer at top center. 
 
It's a daunting modification and probably most won't do it, but it does really slow down the tuning and makes it much easier to tune in a CW station and it's now actually possible to also tune in the SSB stations at the high end if they fall within the tuning range.  The radio is quite stable and once tuned to a frequency I didn't observe any drift after a couple minutes of warm up.  Super job by the designers.
 
Jim - W0EB
 
 
It actually looks pretty decent mounted on the radio - helps a lot with ease of tuning in a signal.
 
 
Closer picture of the installed Philmore S38 vernier dial



Larry Draughn
 

Hi Folks this is what I done to make the Dial fit without buying anymore hardware, I took the 50K pot and clipped off the metal around the thermal flush with the bottom of the Pot, cut approx. ¼ inch off the shaft of the Pot and mounted flat against the PCB, added a set screw in place of the Phillips jam screw on the Dial so you can us an Allen wrench to tighten, That’s it works pretty good. Hope this helps.

 


From: 4sqrp@... [mailto:4sqrp@...]
Sent: Tuesday, January 31, 2017 8:44 AM
To: Jim Sheldon; 4sqrp@...
Subject: Re: [4sqrp] Another mod to the Bayou Jumper

 

 

Hi Jim -

 

I'm trying the vernier dial mod to my BJ. To get an extra 1/8" of clearance for the shaft, I used 3/4" standoffs instead of the 5/8" standoffs. The work to let the vernier shaft just clear the pot, but now all of the other pot shafts are too short to be engaged by the supplied knobs.

 

Grinding the vernier shaft down would work, but to get 1/8" it looks like he set screw hole will be compromised.

 

What did you find on your build?

 

Thanks,

Chip

AE5KA

 

On Thu, Jan 5, 2017 at 7:49 PM, 'Jim Sheldon' w0eb@... [4sqrp] <4sqrp@...> wrote:

 

I had a 1.5" diameter Philmore vernier dial laying around so I decided to see how difficult it would be to install for tuning the Bayou Jumper which is sort of fast and difficult, but not impossible, to get just right. 

 

First, it was necessary to drill out the hole in the panel for the tuning pot to a diameter of 7/16" to allow for clearance of the shaft coupler on the vernier.  Next, it was necessary to cut the tuning pot shaft down to just over 1/4" long and the bottom of the shaft coupler still bottomed out on the frame of the pot, leaving the base of the vernier mechanism about 1/8" above the panel.  There are two options here, grind down the shaft coupler until the vernier sits flush with the panel and the coupler doesn't bind on the frame of the pot or use 1/8" or so of spacers between the panel mounting standoffs and the panel (easier at assembly time to add the spacers between the main PC board and the bottom of the standoffs).  The mounting holes for the vernier must be carefully laid out and drilled for 2-56 screws and 2 of these are used to mount it to the panel.

 

Before re-assembling the panel/pc board combination, set the shaft on the tuning pot to mid range and the vernier to midrange (#50).  Carefully fit everything into place, tighten all the panel mounting screws and other top side hardware just like you did on the initial assembly.  Next, very carefully tighten the set screw on the vernier's shaft coupler to lock it to the tuning shaft of the pot.  You will only have 180 degrees of rotation rather than the full 270 degrees but this should fall within the 7020 to 7130 range assuming you had done the calibration steps earlier.

 

I used the 1.5" Philmore S38 vernier.  The S50 is a 2" diameter dial and these are also available for somewhere around the same price or just a little more.  The S38 is the ideal one as it fits within all original markings on the Bayou Jumper's panel where the S50 will cover the word Tuning and the top will extend into, if not completely cover the original V shaped pointer at top center. 

 

It's a daunting modification and probably most won't do it, but it does really slow down the tuning and makes it much easier to tune in a CW station and it's now actually possible to also tune in the SSB stations at the high end if they fall within the tuning range.  The radio is quite stable and once tuned to a frequency I didn't observe any drift after a couple minutes of warm up.  Super job by the designers.

 

Jim - W0EB

 

 

It actually looks pretty decent mounted on the radio - helps a lot with ease of tuning in a signal.

 

 

Closer picture of the installed Philmore S38 vernier dial

 


Jim Sheldon
 

That's another decent way to do it, but remember, if you do use an allen set screw, you'll need a long allen wrench to reach in far enough to tighten it.  There just isn't enough room normally to get a standard size allen driver in there.

Either way, you Will have to snip 1/4" (might need to snip a very little more - depends on the length of the vernier's shaft) off the tuning pot's shaft or you won't get the vernier shaft to go down far enough.

Jim - W0EB

------ Original Message ------
From: "'Larry Draughn' ldraughn@... [4sqrp]" <4sqrp@...>
To: 4sqrp@...; "'CStratton'" <groups@...>
Sent: 1/31/2017 7:50:28 AM
Subject: RE: [4sqrp] Another mod to the Bayou Jumper

Hi Folks this is what I done to make the Dial fit without buying anymore hardware, I took the 50K pot and clipped off the metal around the thermal flush with the bottom of the Pot, cut approx. ¼ inch off the shaft of the Pot and mounted flat against the PCB, added a set screw in place of the Phillips jam screw on the Dial so you can us an Allen wrench to tighten, That’s it works pretty good. Hope this helps.

 


From: 4sqrp@... [mailto:4sqrp@...]
Sent: Tuesday, January 31, 2017 8:44 AM
To: Jim Sheldon; 4sqrp@...
Subject: Re: [4sqrp] Another mod to the Bayou Jumper

 

 

Hi Jim -

 

I'm trying the vernier dial mod to my BJ. To get an extra 1/8" of clearance for the shaft, I used 3/4" standoffs instead of the 5/8" standoffs. The work to let the vernier shaft just clear the pot, but now all of the other pot shafts are too short to be engaged by the supplied knobs.

 

Grinding the vernier shaft down would work, but to get 1/8" it looks like he set screw hole will be compromised.

 

What did you find on your build?

 

Thanks,

Chip

AE5KA

 

On Thu, Jan 5, 2017 at 7:49 PM, 'Jim Sheldon' w0eb@... [4sqrp] <4sqrp@...> wrote:

 

I had a 1.5" diameter Philmore vernier dial laying around so I decided to see how difficult it would be to install for tuning the Bayou Jumper which is sort of fast and difficult, but not impossible, to get just right. 

 

First, it was necessary to drill out the hole in the panel for the tuning pot to a diameter of 7/16" to allow for clearance of the shaft coupler on the vernier.  Next, it was necessary to cut the tuning pot shaft down to just over 1/4" long and the bottom of the shaft coupler still bottomed out on the frame of the pot, leaving the base of the vernier mechanism about 1/8" above the panel.  There are two options here, grind down the shaft coupler until the vernier sits flush with the panel and the coupler doesn't bind on the frame of the pot or use 1/8" or so of spacers between the panel mounting standoffs and the panel (easier at assembly time to add the spacers between the main PC board and the bottom of the standoffs).  The mounting holes for the vernier must be carefully laid out and drilled for 2-56 screws and 2 of these are used to mount it to the panel.

 

Before re-assembling the panel/pc board combination, set the shaft on the tuning pot to mid range and the vernier to midrange (#50).  Carefully fit everything into place, tighten all the panel mounting screws and other top side hardware just like you did on the initial assembly.  Next, very carefully tighten the set screw on the vernier's shaft coupler to lock it to the tuning shaft of the pot.  You will only have 180 degrees of rotation rather than the full 270 degrees but this should fall within the 7020 to 7130 range assuming you had done the calibration steps earlier.

 

I used the 1.5" Philmore S38 vernier.  The S50 is a 2" diameter dial and these are also available for somewhere around the same price or just a little more.  The S38 is the ideal one as it fits within all original markings on the Bayou Jumper's panel where the S50 will cover the word Tuning and the top will extend into, if not completely cover the original V shaped pointer at top center. 

 

It's a daunting modification and probably most won't do it, but it does really slow down the tuning and makes it much easier to tune in a CW station and it's now actually possible to also tune in the SSB stations at the high end if they fall within the tuning range.  The radio is quite stable and once tuned to a frequency I didn't observe any drift after a couple minutes of warm up.  Super job by the designers.

 

Jim - W0EB

 

 

It actually looks pretty decent mounted on the radio - helps a lot with ease of tuning in a signal.

 

 

Closer picture of the installed Philmore S38 vernier dial

 


random.path
 

Thanks Jim and Larry -

I chose to cut the tabs and through hole leads flush with the bottom of the pot so it would sit lower on the board. I passed small pieces of bare wire up through the pcb holes for the three leads to solder to the remnants of the pot leads. This provided plenty of room for the S38 venier shaft to clear the pot frame.

Chip
AE5KA

On Tue, Jan 31, 2017 at 6:45 PM, Jim Sheldon <w0eb@...> wrote:
I used the normal standoffs, cut about 1/4 inch off the tuning pot shaft (maybe a little more) and inserted a couple washers under each standoff to adjust the height to the point that the vernier shaft would just work and still leave enough height on the other shafts to engage the setscrews on the knobs.

Jim 

On Jan 31, 2017, at 7:44 AM, CStratton <groups@...> wrote:

Hi Jim -

I'm trying the vernier dial mod to my BJ. To get an extra 1/8" of clearance for the shaft, I used 3/4" standoffs instead of the 5/8" standoffs. The work to let the vernier shaft just clear the pot, but now all of the other pot shafts are too short to be engaged by the supplied knobs.

Grinding the vernier shaft down would work, but to get 1/8" it looks like he set screw hole will be compromised.

What did you find on your build?

Thanks,
Chip
AE5KA

On Thu, Jan 5, 2017 at 7:49 PM, 'Jim Sheldon' w0eb@... [4sqrp] <4sqrp@...> wrote:
 

I had a 1.5" diameter Philmore vernier dial laying around so I decided to see how difficult it would be to install for tuning the Bayou Jumper which is sort of fast and difficult, but not impossible, to get just right. 
 
First, it was necessary to drill out the hole in the panel for the tuning pot to a diameter of 7/16" to allow for clearance of the shaft coupler on the vernier.  Next, it was necessary to cut the tuning pot shaft down to just over 1/4" long and the bottom of the shaft coupler still bottomed out on the frame of the pot, leaving the base of the vernier mechanism about 1/8" above the panel.  There are two options here, grind down the shaft coupler until the vernier sits flush with the panel and the coupler doesn't bind on the frame of the pot or use 1/8" or so of spacers between the panel mounting standoffs and the panel (easier at assembly time to add the spacers between the main PC board and the bottom of the standoffs).  The mounting holes for the vernier must be carefully laid out and drilled for 2-56 screws and 2 of these are used to mount it to the panel.
 
Before re-assembling the panel/pc board combination, set the shaft on the tuning pot to mid range and the vernier to midrange (#50).  Carefully fit everything into place, tighten all the panel mounting screws and other top side hardware just like you did on the initial assembly.  Next, very carefully tighten the set screw on the vernier's shaft coupler to lock it to the tuning shaft of the pot.  You will only have 180 degrees of rotation rather than the full 270 degrees but this should fall within the 7020 to 7130 range assuming you had done the calibration steps earlier.
 
I used the 1.5" Philmore S38 vernier.  The S50 is a 2" diameter dial and these are also available for somewhere around the same price or just a little more.  The S38 is the ideal one as it fits within all original markings on the Bayou Jumper's panel where the S50 will cover the word Tuning and the top will extend into, if not completely cover the original V shaped pointer at top center. 
 
It's a daunting modification and probably most won't do it, but it does really slow down the tuning and makes it much easier to tune in a CW station and it's now actually possible to also tune in the SSB stations at the high end if they fall within the tuning range.  The radio is quite stable and once tuned to a frequency I didn't observe any drift after a couple minutes of warm up.  Super job by the designers.
 
Jim - W0EB
 
 
It actually looks pretty decent mounted on the radio - helps a lot with ease of tuning in a signal.
 
 
Closer picture of the installed Philmore S38 vernier dial