I have seen crystals go off frequency. Just worked on an R-4C with the 5645 Xtal sitting at 5642. Crystals off by that much cannot be ¡°rubbered¡± to 5645. The solution with that receiver was to replace the Xtal.?
AF4K has them in stock for $25 plus shipping. They aren¡¯t HC-6 (they¡¯re quite small) but they are dead-on.?
You will need to find out which (tx or rx) is off and go from there.?
73,
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Sat, Dec 21, 2024 at 01:46, Tony Sokol via groups.io <
tony.sokol@...> wrote:
? ? Hey Bob, glad to hear that all is well in TN. Yeah, when I fudged the transmitter carrier frequency to net with the receiver is when things got snaky with the USB/LSB imbalance. Sooo¡I went back and adjusted the TX4B¡¯s carrier frequency so it is perfectly balanced between the filters. I used a VTVM to balance the audio output which made the job a little easier. The transmit audio sounds excellent now on both side bands but C61 is maxed out and can¡¯t quite make it on frequency. I tried padding it which didn¡¯t make much difference. Maybe I need more C or the rock has changed over time. I think I need to put it back on the bench and look at the actual frequency with my HP counter at this point.?
Have a Very Merry Christmas and a great New Year my friend. I¡¯ll keep you updated.?
? ? ? ? ?73
Tony - W9JXN?
Dundee, IL
On Dec 20, 2024, at 7:12?PM, Bob Loving via groups.io <bob.loving@...> wrote:
?
HI, Tony.
From your description of bassy on LSB and squeaky on USB, the carrier oscillator is not in the middle of the two sideband filters of the T-4XB. If I were you, I'd adjust the frequency of the carrier oscillator in the T-4XB first to get both sidebands to sound equal. This will be easier with an external receiver other than the R-4B. Then make the adjustment to the R-4B so that received signals sounds correct.
Hey, I have been in Dixie for 9-years and I love TN. I hope all is well in my birth state. Merry Christmas and Happy New Year, my friend.
73,
Bob Loving K9JU
Maryville, TN
On Friday, December 20, 2024 at 07:34:29 PM EST, Tony Sokol via groups.io <tony.sokol@...> wrote:
Thanks Steve.?
? ? ? I did try fudging the transmitter and got them to sync but it went too far. Had great base on LSB but on USB I was accused of having shorts that were too tight. ;-). I think need to check the receive crystal frequency and oscillator components. I noticed the crystal has a green dab of paint on it possibly meaning it was graded for certain circuit anomalies during final assembly.?
Tony
???
On Dec 20, 2024, at 6:41?AM, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:
?
Tony, there is a chance that either the CO crystal in either the TX or RX has drifted or that one of the passband filters in the tx has drifted. I have a set of B Twins that suffered the same problem and I adjusted the CO in the tx just a little bit to allow everything to meet up. Only a very small change of the tx CO is needed.?
C61 only changes the frequency by about 450 Hz. I used the spectrum display in my modern rig (an Elecraft P3 at the time) to watch where the oscillator was via a piece of wire placed near the CO of each unit. A spectrum analyser can do the same thing.?
73,
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Thu, Dec 19, 2024 at 19:11, Tony Sokol via groups.io <
tony.sokol@...> wrote:
Hi Gang,
I have a problem using C61 to net the R4B to the T4XB. The T4XB is perfectly centered in the filter passband according to the alignment instructions in the manual but it doesn¡¯t quite make it. Before I pull the receiver off the shelf and check the IF Xtal frequency I thought I'd run it by the group for ideas. I did try paddling C61 but it didn¡¯t seem to move much. Maybe not enough C paddling? Thoughts before I give K4AX Crystals a call?
Tony - W9JXN
