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Hi Jim.
The manual states 50HZ shift.? I understand you can change the 33pf cap and move it around to your liking. I just was curious as to why this was even happening.
My Second SR2000 has no Carrier osc crystals. I have searched the world over trying to find them.? Nobody makes crystals anymore. Anyone that has a parts rig, wont give them up.
As a result, I have no choice but to put a small Clock generator/oscillator under the deck hidden away.? ?
This is challenging as the radio actually needs THREE channels due to the CW offset.? ?I ran the rig with the two channels programmed on the Clock generator and it seemed to work on all modes.? Side band worked fantastically.??
There is an advantage, You can set the frequency to whatever you want.? This allows you to nail down the pass band perfectly to the aging Lattice filter.? ?My lattice filter has shifted 100 over.? ?So, I can easily program that offset to both sidebands and
bingo, Audio is full, smooth and clear.
I understand why this offset is employed now.? I will do further testing to see if drive is less without the offset.? I have a set of Xtals out of the first rig to swap in.? Then I will disable the offset and attempt to Tune or use CW and see the effect.
If I do need the offset, I will then have to build a third OSC assembly.? Otherwise, CW won't work.? The units I have do not allow you to edit the firmware. Otherwise, I could set an offset with a trigger.
Just trying to save the radio.? In 2024 we have little options for parts now.
C From: [email protected] <[email protected]> on behalf of James Liles via groups.io <hallicrafterssr2000@...>
Sent: Monday, May 20, 2024 8:15 AM To: [email protected] <[email protected]> Subject: Re: [HallicraftersRadios] SR2000 CW Offset ?
[Edited Message Follows] Late to the post.? If the shift is only 50Hz, something is amiss.? Should be as in photo.The offset is used in tune mode also.? ?This could result in underloading the finals and excessive screen current.? Check for exposure by loading the radio up then whistling the radio up while checking ALC level and screen current. Good luck and regards Jim K9AXN? ? ?? Regards Jim K9AXN |
