Info or manual needed. Johnson 2 meter VFO (mobile)

[WQ9E]

Clark,

But what does the manual say for output frequency from the first stage?

Did you try the Globe VFO with the choke in the cathode lead still shorted?  If neither VFO works then I would suspect the transmitter instead of the both VFOs.

How do the voltages look on the oscillator stage according to those called for in the manual?  Have you tried a replacement tube for this stage?

[ke7trp]

In the manual to the transmitter.. It says.

XTAL or VFO. 8 to 9 MHZ. 

Then it says:

OSC control.  Tunes the oscilator plate to the third harmonic of the Xtal or VFO input.

BUFF control.  Tunes the buffer plateto the oscilater FREQ OR uses the Third harmonic of the oscilator to ouput FREQ.

I set the VFO to 8.0222 where I need it.  This matches the xtal. There is no Osc rise. Its like the VFO is not even plugged in.  Very odd. 

This vfo was marketed to sit next to this damn Transmitter.. It has to work.  What boggles the mind is why it works with an Xtal and no the vfo. 

I know the VFO is outputing.. The SX28 in the other room can hear the VFO 15 feet away as I tune it.  So I have confirmed this VFo to be working..

C

[ke7trp]

Why is that a problem?  The VFo and the Xtal match on the input side.   

C

[ke7trp]

I dont own a 6n2 vfo. 

I have a Johnson 2 meter VFO and a Gobe 6-2 VFO. 

I guess the 6n2 works like the others.  I wonder why globe sold this VFO to sit next to the Transmitter when its not compatible. 

I guess it wont work unless anyone has a simple solution.  I guess I will order more xtals.  The one I ordered is a full 8KC down from the net Frequency. Even with a trimmer, Its still 6 KC off before it unlocks.  Maybe I will have better luck with the next xtal

C

[ke7trp]

Thanks for the picture. Now I understand. This one is exactly like that but has no 6 meter.

The Globe Version that does have 2 meter and 6 meter is working FB.  I just looked at the output. The harmonics are low. It has an output filter.  Maybe its made to work with a different model Globe transmitter. 

I think we got to the bottom of this one!  Thanks to everyone who helped out.  I sure learned alot of oscilators. I have been reading books for days and days.. 

Its just my luck that I buy the only 2 meter rig out there that wont work with these VFos.  I guess its time to order yet another xtal.  Maybe I will get closer this time.

I will sell off the Globe 6-2 VFO and the Johnson 2 meter VFO. If anyone wants either, Let me know. I will pass them on for the price I paid.  They are of no use to me now.

Clark

[Pete, WA2CWA]

Thanks for the picture. Now I understand. This one is exactly like that but has no 6 meter.

The Globe Version that does have 2 meter and 6 meter is working FB.  I just looked at the output. The harmonics are low. It has an output filter.  Maybe its made to work with a different model Globe transmitter. 

I think we got to the bottom of this one!  Thanks to everyone who helped out.  I sure learned alot of oscilators. I have been reading books for days and days.. 

Its just my luck that I buy the only 2 meter rig out there that wont work with these VFos.  I guess its time to order yet another xtal.  Maybe I will get closer this time.

I will sell off the Globe 6-2 VFO and the Johnson 2 meter VFO. If anyone wants either, Let me know. I will pass them on for the price I paid.  They are of no use to me now.

Clark

The Globe VFO manual says that the unit was primarily designed for use with the Globe Scout 680-A and the Globe Hi-Bander VHF-62 or any 6 and 2 meter transmitter with suitable multiplier stages.

In the Hi-Bander manual, page 7, Section 3-4, discusses "use with VFO". Page 8 discusses a modification to Hi-Bander transmitters with Serial Numbers beginning with IH, JH, and KH. It requires adding a 10 pf cap between the shield of the coax and the cold end pin of the crystal plug.

[Pete, WA2CWA]

It requires adding a 10 pf cap between the shield of the coax and the cold end pin of the crystal plug.

He might be able to do that to the Johnson VFO as well, but the harmonic levels may still be too low. It's worth a try though.

Even if it doesn't work with his Johnson, his Globe 6-2 VFO isn't working with the Hi-Bander either so try it on that one.

[ke7trp]

My manual does not mention anything about a modification for use with VFO.

I dont understand what you mean by Cold pin.  Are you saying a cap across the VFO output cable?

C

[ke7trp]

This transmitter has no cold side.  Both leads go to the tube.  Sorry for not mentioning that.  I guess I will try the lead that goes tot the cathode.

C

[Pete, WA2CWA]

If you read the Hi-Bander manual, there is a section 3-4 on Page 7 that explains connector of VFO to the rig. Connect center conductor of VFO output cable to the XTAL socket hole nearest to the METER SWITCH. The shield braid of the cable connects to the remaining XTAL socket hole. Page 8 explains the modification I mentioned previously.

Complete manuals are wonderful additions to any rig 

[ke7trp]

I have the manual.  Its from AG tennenbaum.  To bad it does not say anything about this.  I dont have a 10 PF cap.. I have a 20. I will try it in a few minutes after the 40 meter meter group.

C

[ke7trp]

Cap did not work. I tried 5 to 50 pf at the Xtal plug.  I unscrewed the shield from the Xtal plug. Put the cap inline. No rise in current on the osc. 

What a real pain the ass.  Two VFos and a radio.. hours of work. Damn thing wont oscilate.  Oh well. Going to toss it all in the Dumpster.  Thanks for the help guys. I learned alot.  I would wish leo was alive. I would smack his face for making a radio with a tripler in the first stage. What an A-hole.

C

[ke7trp]

There is no shield.  There are two wires. Black goes to Cathode on tube. Green goes to Grid.  Its not shielded anywhere. I can try it at the tube pin if you think that might help.

C

[Pete, WA2CWA]

Get the Globe VFO to work with the Hi-Bander first since it was designed to work with it. Put the Johnson aside until you get the other combo working. This way we all will be on the same page.

[ke7trp]

Its an RCA jack on the back of the VFO. I used an old Collins S line cable. Its coax.  Not sure of the type. Its the type of cable used to link the S lines together. someone cut the end off so I used it.

Its about 2 feet long. Maybe 3. 

The johnson had a piece of RG58 on it.  About 3 ft. 

What I was saying about no shield was about the Transmitter. The Xtal plug on the inside has two wires. No shield and no ground. Both pins are go to the OSC tube.

C

[ke7trp]

tried 75 ohm and 50 ohm coax.  1 ft.  No osc current.  Measured it on the scope. Its a full 10.2 volts output of that VFO cable right into the radio. I can see the VFO signal right at the tube pin. 

It simply will not work.  Pull the VFO line out and put the Xtal in.  It works FB. Full power, Great sound.. Just off 8 damn KC.

To bad. The net starts in 30 minutes.  We all tried our best here. Thanks for all the time guys.

 I have now measured and checked every part in this radio and TWO VFOs.  Nothing at this point will get my 10 hours back. I am going to take it to the range tomorrow and pump the damn thing with lead. Maybe I can get some laughs out of it. I need to shoot my New PPS anyways. 

C

[Jim, W5JO]

Did you feed the VFOs output into a counter to see what frequency they produced?  Use a scope probe (appropriate freq. response) and measre it.  I am curisous to see what you read.

[Pete, WA2CWA]

While looking at the front panel of the Hi-Bander, the center lead of the coax from the Globe VFO connects to the right pin (this pin connects to the grid). Take a short clip lead and just connect the coax shield to ground. Check and see if the two screws holding the crystal socket in place are at chassis ground, and, if so, connect the shield/short clip lead to one of them. You may or may not have to connect a 10 pf or so capacitor from the right pin (where you connected the center conductor of the coax) to the other pin of the crystal socket. Coax cable length from the VFO to the Hi-Bander probably should be around 2 feet or less.

[ke7trp]

Pete. That made the stage a doubler.  16mhz out and then the buffer would not tune.

C

[Pete, WA2CWA]

No reason for it to become a doubler unless L1, or more likely L2, is not adjusted properly.

[ke7trp]

Both of these are adjusted perfect with the Xtal working.  Should I try to adjust them for the VFO?

C

[Pete, WA2CWA]

The L1 adjustment was installed to reduce or eliminate CW chirp. However, to far in either direction would cause the oscillator to stop oscillating. L2, on the plate side of the 5763, should be roughly tuned to 25 mHz. Did you also include the 10 pf cap across the crystal socket pins although I don't see where that would make much difference?

[ke7trp]

Yes. I get osc, buffer, and final current. But the rig outputs on 23MHZ.  Low power. About 5 watts.  Tuned L1 and L2. No change. 

Put the xtal back in, Tuned rig up 20 watts out on 144.444. 

I dont understand why its going to 23. 

C

[ke7trp]

Yes.. Sorry

I did try the cap in series. No Osc dip.

I also tried pulling the RCA out so just the center was in.  I tried Grounding the shield with and without the cap and no ground at all.  I also tried to put the cap across the socket.

I have the Freq counter on a Probe.  It shows a solid 10 volts at 8.0222 where I need it.  ITs actualy stable. Same Freq as the Xtal. I backed the slug out and rotated it in.  I can get a peak but its not the right one. There is no activity on the osc meter with any other slug position.

I keep thinking the trouble is that both xtal socket wires go to the tube. Other schematics dont show this.  They show one grounded.
C

[ke7trp]

I will take my WB reciever in the shop and tune around until I hear the third. 

C