Date
1 - 12 of 12
LO off QRG
Lucijan
Hello !
I am new hire so warm hello for all IC7000 owners.
My rig serve me perfect for 6 years in many UHF SHF test and I am still fascinated with it.
To be quick: my LO is off. On 2m 1,2 kHz and on 70 cm 4 kHz. I am low with LO so I can not reach exact LO of 124.032 . In DDS calibrating routine I tried from OOh to FFh but nothing happens after returning to main menu as additional problem. Of course I press SET button ; )
When I adjusting DDS LO i can see change. This change is not sufficient to be exactly on 124.032. I am always off and little bit down.I can change cca 100 Hz from 00 to FF. When I step out from service routine no change is noticeable on real QRG like DDS service routine doesn't catch. Do I make something wrong?. I tried to find answer from previous messages but I am not sure I get right one. I have USA version of radio and frequency counter. In normal OTH REF Adjustment I can change almost 7kHZ range but always down of proper frequency. Could some other setups interfere? Could I improve situation with master reset?
If someone went true this issue on his radio please advice!
Thanks in advance.
Best regards, Luci , 9A1Z
I am new hire so warm hello for all IC7000 owners.
My rig serve me perfect for 6 years in many UHF SHF test and I am still fascinated with it.
To be quick: my LO is off. On 2m 1,2 kHz and on 70 cm 4 kHz. I am low with LO so I can not reach exact LO of 124.032 . In DDS calibrating routine I tried from OOh to FFh but nothing happens after returning to main menu as additional problem. Of course I press SET button ; )
When I adjusting DDS LO i can see change. This change is not sufficient to be exactly on 124.032. I am always off and little bit down.I can change cca 100 Hz from 00 to FF. When I step out from service routine no change is noticeable on real QRG like DDS service routine doesn't catch. Do I make something wrong?. I tried to find answer from previous messages but I am not sure I get right one. I have USA version of radio and frequency counter. In normal OTH REF Adjustment I can change almost 7kHZ range but always down of proper frequency. Could some other setups interfere? Could I improve situation with master reset?
If someone went true this issue on his radio please advice!
Thanks in advance.
Best regards, Luci , 9A1Z
igor-m <mikki@...>
Hi, the same issue here. EU version, 13y old 7k.
With the OTH menu #51 I get about 4.5kHz diff from 0-100%.
"Luckily" at the 100% setting it is only 5Hz low (at around 20MHz).
While messing with the REF OSC adjust menu (stock hex 9B here) I see none influence on the TX frequency (and yes, I press SET).
I've been measuring the frequency at a dummy load while TXing in AM or RTTY mode.
I would be happy to know for what is the "hex adjust" menu actually good for.
My current understanding is that while changing the hex value I must see a change in the TX frequency..
Any hint plz?
With the OTH menu #51 I get about 4.5kHz diff from 0-100%.
"Luckily" at the 100% setting it is only 5Hz low (at around 20MHz).
While messing with the REF OSC adjust menu (stock hex 9B here) I see none influence on the TX frequency (and yes, I press SET).
I've been measuring the frequency at a dummy load while TXing in AM or RTTY mode.
I would be happy to know for what is the "hex adjust" menu actually good for.
My current understanding is that while changing the hex value I must see a change in the TX frequency..
Any hint plz?
Using my calibrated Agilent 8924C analyzer I see OTH #51 vary by 1330 Hz from 0-100% when measuring the 124.032 MHz 2LO signal at P4. When transmitting on CW or AM at 20 MHz it varies 215 HZ from 0-100%.
In Maintenance mode, adjusting the REF setting from 0-FF changes the 124.032 MHz 2LO by 1300 Hz, but does not affect the TX frequency when returned to normal mode -- just as you saw.
I don't have an explanation for why it behaves that way. But if you have accurate frequency measurement equipment and follow the adjustment procedures, you should have adequate adjustment range in menu #51 to calibrate your TX/RX signal at UHF and below. You should verify that your DDS REF 2LO is at exactly 124.032 MHz. Then perhaps verify your RX frequency in normal mode by zero beating to a commercial transmitter at the highest frequency possible.
It is possible for the X1 VCTCXO reference oscillator to drift with age, but that would only be suspect if can't adjust the 2LO REF signal to 124.032 MHz in Maintenance mode.
Steve, W3AHL
Helmut Wabnig
On Sat, 09 Jan 2021 12:52:18 -0800, you wrote:
Cannot calibrate down, reaches 100 % in menu 51.
What I found is the analog control voltage to the oscillator chip VFO
was off and not in spec. Voltage coming from the CPU box.
The oscillator is at the lower side of the pcb, which made me angry.
:-)
Sold the radio as "defect".
If you have a chance to borrow another 7000,
swap the CPU box to find out what happens.
OE8UWW
Using my calibrated Agilent 8924C analyzer I see OTH #51 vary by 1330 Hz from 0-100% when measuring the 124.032 MHz 2LO signal at P4. When transmitting on CW or AM at 20 MHz it varies 215 HZ from 0-100%.I once had a 700 with exactly this problem.
In Maintenance mode, adjusting the REF setting from 0-FF changes the 124.032 MHz 2LO by 1300 Hz, but does not affect the TX frequency when returned to normal mode -- just as you saw.
I don't have an explanation for why it behaves that way. But if you have accurate frequency measurement equipment and follow the adjustment procedures, you should have adequate adjustment range in menu #51 to calibrate your TX/RX signal at UHF and below. You should verify that your DDS REF 2LO is at exactly 124.032 MHz. Then perhaps verify your RX frequency in normal mode by zero beating to a commercial transmitter at the highest frequency possible.
It is possible for the X1 VCTCXO reference oscillator to drift with age, but that would only be suspect if can't adjust the 2LO REF signal to 124.032 MHz in Maintenance mode.
Steve, W3AHL
Cannot calibrate down, reaches 100 % in menu 51.
What I found is the analog control voltage to the oscillator chip VFO
was off and not in spec. Voltage coming from the CPU box.
The oscillator is at the lower side of the pcb, which made me angry.
:-)
Sold the radio as "defect".
If you have a chance to borrow another 7000,
swap the CPU box to find out what happens.
OE8UWW
igor-m <mikki@...>
@Steve and Helmut: thanks for the hints.
I started to doubt that I can see a change of the TX freq (while changing the hidden adjust hex value) after I had a look in the service manual - the "frequency scheme" picture there.
It could be the changing of the voltage (while changing the maintenance REF OSC hex value) changes the oscillator's frequency actually, but the TX frequency stays unaffected because the change "somehow cancels out" within the frequency scheme. It is not easy to formalize the change from that picture, though.
Hopefully, the setting the master frequency as described in the service manual will help with the aged crystal..
Igor
I started to doubt that I can see a change of the TX freq (while changing the hidden adjust hex value) after I had a look in the service manual - the "frequency scheme" picture there.
It could be the changing of the voltage (while changing the maintenance REF OSC hex value) changes the oscillator's frequency actually, but the TX frequency stays unaffected because the change "somehow cancels out" within the frequency scheme. It is not easy to formalize the change from that picture, though.
Hopefully, the setting the master frequency as described in the service manual will help with the aged crystal..
Igor
igor-m <mikki@...>
On Sat, Jan 9, 2021 at 09:52 PM, Steve W3AHL wrote:
My gut feeling tells me the change of the maintenance mode REF setting from 0-FF must change the TX frequency in AM CW RTTY modes, provided you do not touch the OTH #51.
If the the maintenance mode REF setting from 0-FF "really changes the control voltage of the VCTCXO" then your TX frequency must change accordingly.
No way it stays the same after the return to the normal mode..
Igor
I've asked Icom Europe on this (a week back), none answer yet...
In Maintenance mode, adjusting the REF setting from 0-FF changes the 124.032 MHz 2LO by 1300 Hz, but does not affect the TX frequency when returned to normal mode -- just as you saw.
I don't have an explanation for why it behaves that way. ..
My gut feeling tells me the change of the maintenance mode REF setting from 0-FF must change the TX frequency in AM CW RTTY modes, provided you do not touch the OTH #51.
If the the maintenance mode REF setting from 0-FF "really changes the control voltage of the VCTCXO" then your TX frequency must change accordingly.
No way it stays the same after the return to the normal mode..
Igor
Igor,
There is much that goes on in the firmware that makes it hard to predict how the hardware will work. But the behavior you see is normal. Setting the REF frequency accurately will either solve your problem or tell you there is a problem with the oscillator or the control voltage from the CPU.
Your unit's hex value for REF of 9B is higher than typical in the four radios I have recorded the values for ((typically 55-76), but accurate measurement is the only way to set the frequency so that the IF stages work corrrectly.
Steve, W3AHL
There is much that goes on in the firmware that makes it hard to predict how the hardware will work. But the behavior you see is normal. Setting the REF frequency accurately will either solve your problem or tell you there is a problem with the oscillator or the control voltage from the CPU.
Your unit's hex value for REF of 9B is higher than typical in the four radios I have recorded the values for ((typically 55-76), but accurate measurement is the only way to set the frequency so that the IF stages work corrrectly.
Steve, W3AHL
igor-m <mikki@...>
Steve, when you change the tuning voltage wired to the VCTCXO the TX frequency (measured with a counter at the dummy load) has to change too, imho. The 7000's firmware or hardware has not got any internal means how to determine "how much the frequency of the xtal has changed by applying certain voltage difference". There is none internal reference except the master VCTCXO oscillator.
Thus, when your external counter show 21.000.000 at the TX dummy load with "5F" hex, and you change it to "2C" you must see a change of the TX frequency after returning from the manufacturing menu. The important assumption is there is the "VC" TXCO module soldered on the board, the DAC works and the firmware has not got a bug as well.
Would be great if we will come to an understanding "how the stuff works", as this is a topic people here discussing for a decade already :)
Thus, when your external counter show 21.000.000 at the TX dummy load with "5F" hex, and you change it to "2C" you must see a change of the TX frequency after returning from the manufacturing menu. The important assumption is there is the "VC" TXCO module soldered on the board, the DAC works and the firmware has not got a bug as well.
Would be great if we will come to an understanding "how the stuff works", as this is a topic people here discussing for a decade already :)
cnick6
Hi Steve,
I'm using a Aim-TTI TF930 to measure P4. I just received the counter on Tuesday and was wanting to verify my REF OSC on my 7000. In recent weeks, I noticed it was way off on USB/LSB transmissions in 2m/70cm band. I decided to transmit @ 5% power on 435.000 and used my Airspy R2 to calibrate against that. The R2 is highly calibrated and it seemed to work well. After the adjustment, the USB/LSB was just about perfect. I don't recall my initial calibration value but it was quite a change as I recall. I ended up at 83 versus I think somewhere in the 40s.
Tonight, I discovered that measuring P4 is a bit tricky. I was having an issue just getting a steady reading on the TF930. I realized the connector is not easy to measure. I used a BNC to plunger-clips on the tip and the shield of P4.
At times, the reading seemed stable but only if I was super steady with the connections. I thought I was locked on to 124.032 but my REF OSC value was (oddly) up to DB. After reassembling, I noticed I couldn't transmit. The only thing that changed was the REF OSC value so I reverted that change. Transmit works perfectly and the frequency seems stable.
What's the best way to measure that P4 connector? I'm thinking it might need a test-jig with a female connector on a breadboard.
Thanks!
-Nick, k7cj
I'm using a Aim-TTI TF930 to measure P4. I just received the counter on Tuesday and was wanting to verify my REF OSC on my 7000. In recent weeks, I noticed it was way off on USB/LSB transmissions in 2m/70cm band. I decided to transmit @ 5% power on 435.000 and used my Airspy R2 to calibrate against that. The R2 is highly calibrated and it seemed to work well. After the adjustment, the USB/LSB was just about perfect. I don't recall my initial calibration value but it was quite a change as I recall. I ended up at 83 versus I think somewhere in the 40s.
Tonight, I discovered that measuring P4 is a bit tricky. I was having an issue just getting a steady reading on the TF930. I realized the connector is not easy to measure. I used a BNC to plunger-clips on the tip and the shield of P4.
At times, the reading seemed stable but only if I was super steady with the connections. I thought I was locked on to 124.032 but my REF OSC value was (oddly) up to DB. After reassembling, I noticed I couldn't transmit. The only thing that changed was the REF OSC value so I reverted that change. Transmit works perfectly and the frequency seems stable.
What's the best way to measure that P4 connector? I'm thinking it might need a test-jig with a female connector on a breadboard.
Thanks!
-Nick, k7cj
Nick,
At 124 MHz it is important to keep a relatively constant impedance path from P4 to the counter. My 8924C has 50 ohm inputs and I used a 50 ohm 500 MHz rated scope probe, with a short barrel connector to connect the center pins of P4 and the probe. I had a spring adapter that slipped over the ground barrel of the scope probe and over the outer shell of P4. I suspect that any non-coaxial adapters might introduce enough reflections in the signal path to cause the intermittent readings you saw.
Steve, W3AHL
At 124 MHz it is important to keep a relatively constant impedance path from P4 to the counter. My 8924C has 50 ohm inputs and I used a 50 ohm 500 MHz rated scope probe, with a short barrel connector to connect the center pins of P4 and the probe. I had a spring adapter that slipped over the ground barrel of the scope probe and over the outer shell of P4. I suspect that any non-coaxial adapters might introduce enough reflections in the signal path to cause the intermittent readings you saw.
Steve, W3AHL
cnick6
Steve, I'm using a cheap BNC to "Mini Test Clip" 50 ohm coax cable. Similar to this: https://a.co/d/5stAcq1
You're right in that I probably was getting reflections -- that would make sense -- especially with these cheap cables. I found the P4 female PCB connector parts and will just make a short coax lead that I can plug directly into the TF930. I decided to calibrate from the other direction. With my 83% REF ADJUST value I transmitted on 446.0 Mhz and was only a few hertz off. I am up to 88% now and when I transmit, it's exactly on 446.000000 Mhz. That should suffice for now. :)
Cheers,
-Nick, k7cj