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Using the PLJ-6LED digital display with the R4C

 

Hi Mark.? With the T4X connected to the injection line, are you able to get an accurate and stable readout on the counter on 10 and 15 meters?? I see you're in Doylestown - used to ride the bicycle to Doylestown through Rogues Hollow.? I was located in Jackson Township at that time.
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73, Floyd - K8AC
 

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There is no problem on 10-15? mtrs. They act just like 160-20.? I have two 'C' lines and both act the same. You might try ditching the coupling cap and see what results you get. I've done that before and it seemed to work OK.?
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I live just up the hill from Rogues Hollow just off Route 21, a small world.?
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73's,
Mark, WB0IQK
 

On Fri, Jan 10, 2025 at 12:39 PM, Mark - WB0IQK wrote:
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There is no problem on 10-15? mtrs. They act just like 160-20.? I have two 'C' lines and both act the same. You might try ditching the coupling cap and see what results you get. I've done that before and it seemed to work OK.?
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I've been testing the readout in an external housing, coax connected to the INJ jack on the R4C? Right now I have no coupling cap at all and still having problems on 15 and 10.? I haven't paid any attention to the capacitance of the connecting coax, but I probably should.? May have some old RG-62 around here somewhere and I think that has fairly low capacitance per foot.? I wonder if you've ever measured the signal voltage you see at the counter input on each band?
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73, Floyd - K8AC
 

Floyd,
How about putting your scope on the injection line and peaking each band for maximum signal instead of using Drake's procedure? You might be able to get a bit more output that way.?
Mark
 

Wouldn't the probe load the INJ line by around 2 pF?

Steve Wedge, W1ES

Time flies like an arrow.? Fruit flies like a banana.

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On Monday, January 13th, 2025 at 9:22 AM, Mark - WB0IQK <mgilger@...> wrote:

Floyd,
How about putting your scope on the injection line and peaking each band for maximum signal instead of using Drake's procedure? You might be able to get a bit more output that way.?
Mark
 

Finally got this working well.? First, I installed a 7 pin DIN connector in place of the 4 pin Accessory connector on the rear of the R4C.? I connected the INJ jack to this connector using a piece of RG-62 low capacity coax inside the rear of the chassis.? Next I replaced the small diameter coax I was using to feed the counter with a piece of RG-62 (about 18" long) running from the DIN connector to the counter.? The counter is now perfectly stable and accurate on all the bands, including the 28.5 - 29.0 section of 10 meters.? If the transistors ever get here, I'll add the buffer amp inside the counter enclosure.
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Anyone interested in doing this mod with the counter in an external enclosure: The chassis mount DIN connector fits the holes left by removing the accessory socket, provided you use 4-40 screws instead of the original 6-32s.? Working with the rather stiff RG-62 is a pain and you may be able to use more flexible smaller coax if you add the buffer amp to the counter that was mentioned in a previous post.? Thanks to all for the comments to my original post.
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73, Floyd - K8AC

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