best i can get it

[1iwilly]

i got this yaesu ft-890 a few days ago everything is working fine except i notice that on transmit 27.3850 was showing 27.3853
i found a service manual and after taking radio apart to make the adjustment TC1002 calls for 10.485760 or 120 mv
after 1/2 hour of adjusting the best i can get it to settle is 10.4858 which made the transmit at 27.3851 i figure close enough
compared to 27.3853 with the volt meter 1.40 didn't change at all while turning trimmer

 

[KneeBiter]

Adjusting a Yaesu to match that counter is probably not a good idea.

 

[1iwilly]

i just realised it says to use an RF millivolt meter, not a digital one
i need more coffee LOL

 

[1iwilly]

Adjusting a Yaesu to match that counter is probably not a good idea.

it says counter on the service manual

 

[Xracerx13]

I used the tone at 15Mhz to zero beat. There's one at 10Mhz also. That is the best way.
That external frequency counter you have is not accurate at all in any way

 

[1iwilly]

I used the tone at 15Mhz to zero beat. There's one at 10Mhz also. That is the best way.
That external frequency counter you have is not accurate at all in any way

i was using the external as a reference only i was more relying on the one reading at 10.4858 at TP1004

 

[1iwilly]

I used the tone at 15Mhz to zero beat. There's one at 10Mhz also. That is the best way.
That external frequency counter you have is not accurate at all in any way

i can find that info can you tell me how to do it i found 10.000 has a beat

 

[brandon7861]

This process hardly applies to that frequency counter, not enough digits. Especially on sideband, you want the accuracy withni about 20Hz, but that frequency counter cannot see below 1kHz.

If you get a better external counter, this is how to do it.

1. Turn everything on and walk away for an hour
2. Tune radio into WWV (doesn't really matter what the radio says on display, just so you can hear WWV
3. Adjust signal generator so that the signal is just strong enough to interfere with reception and adjust frequency until it creates a beat in the receiver. As you approach the same frequency as WWV, the beats will slow down in proportion to the difference in frequency between the gen and WWV's signal.
4. Once you get the gen stable on WWV's freq, adjust the counter to read 10MHz via the internal osc adjustment.

The problem with doing this on that external counter is that it will stop changing long before you reach zero beat, not enough digits... And I ran out of paper, so I scribbled it on a box.

 

[Xracerx13]

Its like tuning a guitar.

 

[1iwilly]

i guess i have to buy 2 different meters for this radio on SSB before their voice sounded clear since the adjustment now i have to use a clarifier to clear the audio up so i put it back to the way it was before the adjustment. thanks, guys for the help/advice waiting for this antenna to come in today

 

[Dr_DX]

it says counter on the service manual

To set the Reference Oscillator properly, according to the instructions, it requires an 8 digit frequency counter with 1Hz resolution to be connected to the TP. It has to be able to read 10.485760 +/- 5Hz MHz

If you are going to be working on radios, it is a must have.

Also, do yourself a favor and if the radio doesn't have one, it is money well spent IMHO to put in a TCXO. They usually aren't that expensive.

It appears to me that your external F counter has a resolution of 100Hz and is reading about 300Hz high. I doubt it has a TCXO, so your best bet would be to use the radio to calibrate it (if the counter has an internal adj.). For the most accuracy calibrate it on a freq. where it will be most used, i.e. 27 MHz

Good Luck