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 Post subject: need a idiot's guide to tuning a Johnson Ranger
PostPosted: Sep Tue 07, 2021 3:04 am 
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Joined: May Thu 09, 2019 12:06 am
Posts: 243
Location: Charlotte NC
I am new to the Johnson Ranger and the tuning procedure in the owners manual is a little confusing to me. I would really appreciate it if someone could give me a simple guide to tuning this lovely transmitter.


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 Post subject: Re: need a idiot's guide to tuning a Johnson Ranger
PostPosted: Sep Tue 07, 2021 8:00 pm 
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Joined: Jul Fri 05, 2019 8:30 pm
Posts: 315
Location: West Concord, MA
Sadly, I sold my old Ranger a few years ago. I demo’d it by loading it up into a 60 watt incandescent light bulb (as described in the original EF Johnson manual). The ham I was selling it to was alarmed: “What?? No dummy load???!!!:(


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 Post subject: Re: need a idiot's guide to tuning a Johnson Ranger
PostPosted: Sep Thu 09, 2021 6:16 am 
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Joined: Oct Tue 11, 2016 4:41 am
Posts: 294
Location: Alexandria, Virginia
I think if you follow the tune up steps a couple times you'll feel comfortable doing it without a guide.

Brad K4RT


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 Post subject: Re: need a idiot's guide to tuning a Johnson Ranger
PostPosted: Sep Thu 09, 2021 7:49 am 
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Joined: Nov Mon 02, 2009 7:01 am
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Location: Lincoln City, OR 97367
Greetings to rhrailfan and the Forum:

(A moderator added this link to the video which had previously been deleted: https://www.youtube.com/watch?v=7ZLnomQ0Ckg )

Gad! Whatever you do, do not take anything from that horrid video! The individual who made it does not appear to understand what he is doing; he surely is abysmal at communicating it if he does.

It is a good idea to understand a little about the transmitter circuitry before attempting to tune it; if you know how it works, the steps become intuitive.... otherwise, they can seem arcane.

The tuning controls on the Ranger can be divided into two groups: One to select the frequency of operation and the other to tune the RF stages at that frequency.

The first group consists of the BAND switch (selects the desired frequency band of operation) and the VFO tuning knob and CRYSTAL / VFO switch which together determine the frequency of operation within that band.

The second group adjusts the resonance frequency and degree of coupling of the buffer and final (PA or Power Amplifier) stages. This group consists of the BUFFER and DRIVE controls (which control the buffer stage) and the FINAL, AUXILIARY COUPLING and COUPLING controls which control the PA tuned circuits.

Once you have selected the desired frequency of operation, proceed to tune the transmitter as follows:

Set the OPERATE switch to TUNE and close the key.

The BUFFER control tunes the plate circuit of the buffer stage to resonance. Since the output power of the buffer stage appears as grid current in the PA tube, the stage is metered by looking at the grid current of the PA tube. This function is selected for the meter by operating the METER switch to the GRID position. The power output of the buffer stage is controlled by the DRIVE control. To tune the buffer stage, advance the DRIVE control to about 1/3 of its rotation and rotate the BUFFER control for a peak in the grid current indication. Then adjust the DRIVE control for 2.5 mA on the 10 mA scale of the meter. If the grid current was low when first peaking it or the meter does not show a peak, advance the DRIVE control slightly and re-peak the BUFFER control. Approximate scale readings for this control for each band of operation can be found in the manual. Note that these scale readings depend on the skirted knob being properly installed. If in doubt, check its position.

Once you have the buffer stage tuned, proceed to tune the PA stage as follows:

Set the OPERATE switch to CW. Set the METER switch to PLATE. Set the AUXILIARY COUPLING to 1 and the COUPLING control to about 1/3 scale.

Close the key and immediately adjust the FINAL knob for a minimum reading on the meter. Do not close the key for any longer than is necessary to locate this dip.... one or two seconds at the most. If you cannot locate a dip within a second or two, open the key and check the positions of your controls. Reducing the COUPLING control to 1/4 scale may help. If you still cannot see this minimum in plate current, there is a fault and the problem must be corrected.

Once you have the FINAL control tuned for minimum plate current, you have adjusted the PA tank circuit (plate circuit) to resonance. Release the key. It is now necessary to properly "load" the transmitter. The plate current dip should have occurred at a fairly low value... less than 100 mA on the 200 mA top meter scale. Now advance the COUPLING control slightly and close the key. Again, IMMEDIATELY re-adjust the FINAL control for a dip (minimum current). Note the value and release the key. The value of the plate current should be higher at resonance than before because more energy is being coupled out of the PA plate circuit into the load (antenna or dummy load). If the plate current at the dip is less than 150 mA (120 mA for phone), release the key, advance the COUPLING control and again close the key, while immediately tuning the PA to resonance with the FINAL control. The current at the dip should now be higher. Continue this process of gradually increasing the coupling while tuning the FINAL to resonance until the correct plate current is obtained at the minimum (again, 150 mA for CW; 120 mA for phone).

If the plate current remains too low at the dip with the COUPLING control at maximum, advance the AUXILIARY coupling switch one position clockwise. Turn the COUPLING control down to about 1/3 scale and again key the transmitter and adjust the plate current to a minimum with the FINAL control. Continue the above procedure, gradually advancing the COUPLING control until the desired plate current at the dip is achieved. If the plate current is still too low with the COUPLING control at its maximum setting, return it to near the low end of its range and advance the AUXILIARY COUPLING switch one more position. Continue this process, each time re-tuning for a dip in plate current until the desired value of plate current at resonance is achieved. If the plate current remains too low at the dip with both coupling controls set to maximum, there is a fault which must be remedied.

Hopefully, this will get you going.

Regards,

_________________
Jim T.
KB6GM


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 Post subject: Re: need a idiot's guide to tuning a Johnson Ranger
PostPosted: Sep Thu 09, 2021 8:13 am 
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Joined: Apr Tue 19, 2011 6:24 am
Posts: 508
Location: Wayne, NJ 07470
Jthorusen provided a very clear explanation of what's involved along with a concise set of well-written step-by-step instructions. His words exemplify good technical writing.

His post should be printed and attached to your Ranger's manual as a reference; also, put a copy on the wall near your TX.

Jim's kindness and all the time he spent writing and testing his instructions are recognized and appreciated.

Thank you, OM!

73,
OTH

(ps - No Ranger here anymore, but I smile at the thought...)


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 Post subject: Re: need a idiot's guide to tuning a Johnson Ranger
PostPosted: Sep Thu 09, 2021 12:58 pm 
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Joined: Oct Sun 15, 2006 12:57 pm
Posts: 7902
Location: Liberty, Missouri
Although Jim addressed the issue in his write-up, he does not specifically point out one very important caveat that applies to most any old tube transmitter and tune-up process.

The currents in the antenna loading circuit of transmitters can be quite high, sufficiently high in fact, to damage or more accurately, actually vaporize the wafer switch contacts of the AUX (coarse) loading control if you were to rotate the switch while the transmitter is keyed. The same is true for the "Band Switch".

Johnson's AUX coupling control should more accurately be called the Coarse loading control. It switches relative large value capacitors in and out of the low impedance antenna loading circuit. In order to avoid sometimes irreversible damage to an old boat anchor, NEVER adjust the AUX (coarse) coupling load switch when the transmitter is keyed (transmitting).

The same caveat applies to antenna tuners and linear amplifiers, having such controls, regardless of what the control is "called".

========

As a general rule, never start any tuning process, be it a transmitter, or antenna tuner, at some "high" power level, that's a recipe for disaster, and at best, its not kind to the equipment. Always start with the drive/power controls set to some relatively low setting, maybe 10-20% of full scale. Then proceed to adjust the following stages according to the instructions. Repeat the process as you increase the power in "steps" until you reach the desired output power level.

_________________
Pics, Bold & underlined text, are usually links.

https://mikeharrison.smugmug.com/

Mike


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 Post subject: Re: need a idiot's guide to tuning a Johnson Ranger
PostPosted: Sep Fri 10, 2021 3:18 am 
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Joined: May Sun 22, 2011 11:27 pm
Posts: 409
Location: Dallas,TX
"Gad! Whatever you do, do not take anything from that horrid video! The individual who made it does not appear to understand what he is doing; he surely is abysmal at communicating it if he does."

Thanks, I thought it was just me. :shock: :roll:

_________________
KE5YTV


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 Post subject: Re: need a idiot's guide to tuning a Johnson Ranger
PostPosted: Sep Fri 10, 2021 3:32 am 
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Joined: May Thu 09, 2019 12:06 am
Posts: 243
Location: Charlotte NC
I had watched that video before I made this post about proper tuning. It is a mess lol. A big thanks to those that responded.


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 Post subject: more Johnson Ranger questions
PostPosted: Sep Sun 12, 2021 2:47 am 
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Joined: May Thu 09, 2019 12:06 am
Posts: 243
Location: Charlotte NC
Question 1: Should I be getting a plate current reading on the meter with the transmitter in standby? It is a low reading.

Question 2: With my receiver set at the frequency I intend to talk on and the transmitter in standby when I tune the VFO of the transmitter to the frequency I am going to transmit on it pegs the receiver S meter and overloads it to where I am unable to hear anything. I am still learning here but I thought the VFO of the transmitter should only be running during key-up.


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 Post subject: Re: more Johnson Ranger questions
PostPosted: Sep Sun 12, 2021 8:32 am 
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Location: Lincoln City, OR 97367
Greetings to rhrailfan and the Forum:

It would appear that your Ranger has some difficulty.

My Ranger shows about 30 mA of plate current in standby. This is the clamper tube current. In CW, key up, it shows about 45 mA.

When properly tuned and loaded, I have 150 mA of plate current on the top 200 mA scale, which is the correct value for 75 watts.

The VFO and crystal oscillator / multiplier stages are keyed. The buffer and final amplifier are protected against loss of drive by cathode bias and a clamper circuit respectively. Thus, only the first two stages are keyed in the CW mode.

You may wish to note the readings you get in the CW mode. With a key inserted and not closed (key up), the OSC, BUFF and GRID meter readings are all zero. With key down (switch closed), my oscillator reads about 27 mA on the 40 mA scale, while my buffer reads 10 mA on the same scale.

In the STBY mode, the key has no effect; all readings (except for the small plate current) are zero.

There are two modifications for the Ranger that may be related to your problem. One is the PTT (Push To Talk) modification. If your Ranger is so equipped, there will be a DPDT relay behind the OPERATE switch. Should you have PTT installed and the PTT line is shorted or the relay is stuck down or a similar difficulty, the transmitter is effectively keyed when in the PHONE and TUNE modes. It should not be keyed when in the standby mode, but as I do not have a PTT microphone wired for my Ranger (I use it on CW exclusively) I cannot give you a correct description of its behavior in that mode. Suffice it to say that with the CW key up there is no output from the oscillator or buffer stages in standby. These stages do operate in PHONE mode when the key is closed, but there is no RF output indicated on the plate current meter. (My Ranger has the PTT mod installed; I suspect the fact that there is no PTT signal present due to no microphone being connected prevents the final amplifier from operating.)

The second modification is grid block keying. (Early versions of the Ranger were cathode keyed.) If your Ranger is equipped with the grid block keying modification, there will be a small sub-chassis installed on stand-offs above the OPERATE switch with two miniature tubes in it... a 6AL5 and a 12AU7. A problem in this circuit may lead to the oscillator and multiplier stages operating when such operation is not desired.

Under normal conditions, the oscillator and the multiplier stages may be energized in order to "spot" the VFO on a receiver by rotating the CRYSTAL / VFO switch to the "ZERO" position. Be sure that the knob for this switch is correctly indexed also, else you may be in this mode when you think you are in VFO mode.

If you have the manual, a careful read of section "B" which is theory of operation should be helpful.

Good Luck,

_________________
Jim T.
KB6GM


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 Post subject: Re: more Johnson Ranger questions
PostPosted: Sep Sun 12, 2021 12:58 pm 
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Joined: Oct Thu 01, 2020 10:48 am
Posts: 91
There were three versions of the Ranger through its production run, if I remember correctly. That's the Ranger I, and not including the early '60s Ranger II.

In addition, by now the Rangers have passed through many owners and there are zillions of modifications out there on-line for this rig because so many were made and sold.

So this means you'll probably have to get comfortable with your disconnected Ranger on a table with a bright light and ohm meter, examining the wiring & trying to figure out what you have and making sure your schematic is correct for the unit in front of you, minus any ham mods. This means among other things, tracing through the two wafer mode switch, which I found to be tedious and kind of frustrating, partly because it's hard to get a good look at it. Some modifications can be easy to spot. Mine had a partially finished but non-functioning PTT attempt using a six volt relay that didn't pull in because the filament v. wasn't enough. I took all that out.

You may or may not enjoy this, depending on your experience and disposition. You'll certainly learn some things which is always a benefit.

But based on my experience, I advise hams who are new to vintage gear to avoid Rangers and look for something else like a Viking 1 or 2 with an outboard VFO. Bigger rig but much easier to deal with in my opinion. Ranger's appear to be an ideal newbie rig because of their size and all-in-one construction but that size and design also make them tricky and you can quickly get lost. Some fellows think they're a perfect starter rig but maybe they got a nice model all fixed up and plug and play ready. Anyway, good luck--they're not impossible but you may need some patience.


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 Post subject: Re: need a idiot's guide to tuning a Johnson Ranger
PostPosted: Sep Sun 12, 2021 5:42 pm 
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Joined: Jun Sun 19, 2011 2:31 pm
Posts: 8003
Jim and Rob both gave you good advice.

The Ranger was very popular as were modifications for it so in addition to all of the factory revisions, there could be different additional modifications. I tend to keep gear very stock BUT I made some changes to the Ranger I use to drive my Desk KW to avoid some of the heat it generates and to provide better protection for the Desk KW.

Do you have a CW key plugged into the jack? It is a shorting jack so in the CW position (and other positions depending upon modifications), if there isn't a key in place that is open then at least part of the exciter chain will be keyed constantly.

The very earliest Ranger run doesn't have a CW differential keyer circuit, later ones do and if you don't have it adjusted properly (or if the bias supply caps have been neglected) then you will find the VFO is always keyed. The adjustment controls how long the VFO remains keyed after key up and it should remain so for an extremely short period of time, if adjusted wrong then the VFO is always running. The keyer circuit turns on the VFO slightly before keying the rest of the exciter chain and holds the VFO on slightly after the rest of the exciter chain is unkeyed to avoid the aberrant behavior that comes from a keyed VFO.

Some plate current is normal in standby because of the clamper tube current draw as explained by Jim. To meet size and cost targets, the Ranger doesn't have a separate plate transformer so HV is always present and the clamper tube pulls final screen voltage down to the point where it cuts off the final. The amount of current drawn depends upon the clamper tube characteristics along with the screen voltage to the clamper tube which is controlled by the tap on the HV bleeder resistor which also controls modulator screen voltage/operating class/idle current.

Rodger WQ9E


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 Post subject: Re: need a idiot's guide to tuning a Johnson Ranger
PostPosted: Sep Sun 12, 2021 10:29 pm 
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Joined: May Thu 09, 2019 12:06 am
Posts: 243
Location: Charlotte NC
Since I intend to run on AM phone I did not purchase a CW key. Should I get one and see if that cures the VFO always running issue or is there something I could use to mimick a key being plugged in?


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 Post subject: Re: need a idiot's guide to tuning a Johnson Ranger
PostPosted: Sep Sun 12, 2021 10:49 pm 
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just plug in a mono 1/4 inch phono plug with no connections if you want to disable it. How this will affect the rig depends upon how it was modified but for Johnson (and most other) transmitters of that era, it was assumed that you had a key plugged in.

Do NOT plug in headphones, a speaker, or any 1/4" plug that is connected to anything but a key, bug, or keyer into that because it has voltage across it.

Rodger WQ9E


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 Post subject: Re: need a idiot's guide to tuning a Johnson Ranger
PostPosted: Sep Mon 13, 2021 3:31 am 
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Joined: May Thu 09, 2019 12:06 am
Posts: 243
Location: Charlotte NC
I will give that a try ASAP and see what happens


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