Welcome, Jerry !
You’ll find helpful, friendly folks here.
Among the rigs in my radio-overpopulated-shack are a Valiant and a Navigator along with a couple of Messengers converted to 10 meters.
Thanks for joining us!
Mike/
K5MGR
____________________________________ ? Mike Langner
929 Alameda Road NW
Albuquerque, NM 87114-1901
(505) 898-3212 home/home office
(505) 238-8810 cell
mlangner@...
?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of W0PWE via groups.io
Sent: Tuesday, April 1, 2025 2:50 PM
To: [email protected]
Subject: [EFJohnson-Amateur-Radio] New Member? I just found this group and subscribed so I thought I would say hello. EF Johnson gear has always appealed to me and I have fond memories of the Viking II I used as a Novice in 1970. I didn't own another EFJ transmitter until very recently when a friend and former colleague gave me a Viking Challenger that had been stored in his basement for the last 50 years.? Bringing the Challenger back to life has presented some challenges (pun intended I guess). After new PS capacitors, power cord and internal fuse it acted like it wanted to go but after a few minutes of operation the 15 ohm meter shunt went up in smoke. I think I have found the root cause for that and have it under control but I need to do more work on it.? My Challenger came with some mods. Someone replaced the 6DQ6A finals with 6146s. It has a 6AU6 and some mods in the oscillator circuit. It has (had) the PTT mod. I removed the PTT mod in the process of trouble shooting the run away plate current problem. Not sure if I will restore the PTT mod or not as I mainly want this transmitter to be a Novice rig.? Anyway, I'm glad I found this group and I look forward to reading and taking part in the discussions.
|
I just found this group and subscribed so I thought I would say hello. EF Johnson gear has always appealed to me and I have fond memories of the Viking II I used as a Novice in 1970. I didn't own another EFJ transmitter until very recently when a friend and former colleague gave me a Viking Challenger that had been stored in his basement for the last 50 years.?
?
Bringing the Challenger back to life has presented some challenges (pun intended I guess). After new PS capacitors, power cord and internal fuse it acted like it wanted to go but after a few minutes of operation the 15 ohm meter shunt went up in smoke. I think I have found the root cause for that and have it under control but I need to do more work on it.?
?
My Challenger came with some mods. Someone replaced the 6DQ6A finals with 6146s. It has a 6AU6 and some mods in the oscillator circuit. It has (had) the PTT mod. I removed the PTT mod in the process of trouble shooting the run away plate current problem. Not sure if I will restore the PTT mod or not as I mainly want this transmitter to be a Novice rig.?
?
Anyway, I'm glad I found this group and I look forward to reading and taking part in the discussions.
73 - Jerry - W0PWE
|
|
|
Re: 6N2 with a Clegg Thor modulator/supply
Good morning Bob,
That is exactly what I was after. I planned to use an external speech amp I already have and supply filament externally if necessary. The Thor unit has an output connection to monitor plate current. I was concerned about impedance mismatch. I’m still looking for alternatives. Finding a Thor rf deck would be the best solution but still have the option of modifying one of my Viking units. All this will become unnecessary once I get the Zeus in house and working, so I don’t want to get too carried away.
?
Thanks for taking the time to help! Have a great weekend.
Tom N5AMA
|
Re: 6N2 with a Clegg Thor modulator/supply
On 3/27/2025 9:12 AM, Tom Smith via
groups.io wrote:
Does anyone
have any experience mating a 6N2 with the Clegg Thor
supply/modulator?
Hi Tom,
I haven't done that combination but I have
used the Clegg Thor modulation-power supply with a couple of
transmitters that don't have one,? including the little Palco
Bantam 65 and an ARC-5 transmitter.? As long as you stay within
the limits of the available filament and plate currents I'd
think it should be OK.???? Obviously some Franken-radio
engineering will be required!
Since the Thor RF deck includes the speech
amplifier and high-level audio is sent over the cable to the
modulator,? you'll have to come up with some kind of mic
preamp.? I don't recall the details but I remember using a
little LM-386 board for the job,? and by careful selection of
pins on the connector it didn't disturb the normal operation
with the Thor RF deck.?? I removed some unnecessary panel
component to add a mike jack without drilling extra holes.
73, Bob W9RAN
|
6N2 with a Clegg Thor modulator/supply
Does anyone have any experience mating a 6N2 with the Clegg Thor supply/modulator? I’m trying to put a 6N2 on 6m AM for some local rag chewing and really not interested in modifying either of my Viking 1 or 2 transmitters to work with the 6N2. I think I should be able to cobble up a cable between the two if it makes sense.
?
I would go with the Thor transmitter and supply but can’t locate a Thor transmitter. Any help appreciated.
Tom N5AMA?
|
Looking for a Johnson Invader
Still looking for an Invader (NOT Invader 2000).? If you have one to sell and are going to Dayton, here's your chance to sell it without having to ship.? Or, I might be willing to come and get it.??
?
73, Floyd - K8AC
|
Jeff,
If you use a lathe, be careful.? The aluminum of the cap is 'dead
soft' for forming and about any type of tooling you use will grab
the can with really bad result.
'If' you could mount a Dremel tool with a disk cutter on the tool
post and MANUALLY rotate the chuck, you should wind up with a
decent looking cut.??
If the cut is good and smooth, you could probably take both
edges, cap body and base, and further smooth them by lapping them
with fine grit sandpaper on a very flat surface, like thick glass
plate.? Joint will only be minimally visible.
73 de Steve, NR4M
On 3/19/2025 12:28 PM, jeffbauman via
groups.io wrote:
toggle quoted message
Show quoted text
Thanks, Don.
?
I used wide metallic aluminum tape for the cover.? It would
have worked perfectly had I done a better job of cutting the
can.
?
I used a tubing cutter and I anticipated the ratty result -
no surprise here.
?
Next time I will chuck the cap in my lathe using something
like this ...
?
WEN
LA4444 4-Inch 4-Jaw Self-Centering Chuck Set with 1-Inch x
8TPI Thread
?
..
and just lay a hacksaw against the rotating can for what I
believe will be a smooth cut.
?
73,
Jeff
W8KZW
|
Thanks, Don.
?
I used wide metallic aluminum tape for the cover.? It would have worked perfectly had I done a better job of cutting the can.
?
I used a tubing cutter and I anticipated the ratty result - no surprise here.
?
Next time I will chuck the cap in my lathe using something like this ...
?
WEN LA4444 4-Inch 4-Jaw Self-Centering Chuck Set with 1-Inch x 8TPI Thread
?
.. and just lay a hacksaw against the rotating can for what I believe will be a smooth cut.
?
73,
Jeff
W8KZW
|
You can find a thin cardboard tube that fits over it and paint it silver to match. Many caps from that era had a paper outer wrapper. Donald KX8K On Mon, 17 Mar 2025 09:34:17 -0700, "jeffbauman via groups.io" <jeffbauman@...> wrote: Not too happy with my handiwork restuffing the can, but it was my first attempt - better job next time I promise. ---------------------------------------------------- Some ham radio groups you may be interested in: /g/ICOM /g/Ham-Antennas/g/HamRadioHelp /g/Baofeng/g/CHIRP
|
Happy to report the TR switch is in-line and did an awesome job between my homebrew TX and Drake 2B / Lafayette HA-350 during Novice Rig Roundup!
?
Not too happy with my handiwork restuffing the can, but it was my first attempt - better job next time I promise.
?
?
I just flipped the RX to Standby and used my old keyer to monitor my sending.
?
Now I just have to put my old Hallicrafters S-107 in the lineup to complete my WN2SCH station.
?
73,
Jeff
W8KZW
|
Free For Postage, Johnson Ranger variable capacitor sets (4)
Hello ?? Free for Postage, USPS Flat Rate Box, ($30), to the Lower 48 only.
Johnson Ranger 1 & 2 variable capacitor set (4 sets) Sets consist of: ?? Main Tuning Variable Two-section Capacitor ?? Loading Variable capacitor ?? Buffer Tuning Variable capacitor NO MOUNTING HARDWARE EXCEPT THAT WHICH IS PERMANENTLY ATTACHED TO THE CAPACITORS.
Capacitors are in great mechanical shape, bearings oiled and tested. Units not cleaned.
We are cleaning house a bit, we have several sets of these capacitors ( started out with a few, left them un-watched and unattended, soon there were two boxes full).
Main Tuning Loading Buffer Tuning
Thank You
Ashley
?
?
Thank You
Kiss-Electronics
Ms Ashley Hall
183 N 5th PL.
Cornelius, Oregon
97113
?
?
W7DUZ
?
?
|
The harmonics are not just VHF, they are HF. If you are on 7 MHz the TR switch will generate 14, 21, 28, and so on.?
I'm not saying that is a problem that will "bite" everyone, but it will certainly be there. I forgot exactly what I measured but this is even a problem when solid state diodes are used to generate voltage for relay transfers and other things.
When the grid is rectifying RF the harmonics from the clipped waveform couple directly back via C2 into the transmission line. Whether someone notices a problem depends on how well the antenna radiates a bothersome harmonic.
As for the output voltage, every tube radio I have seen (and many solid states) would take that okay. It could be reduced if necessary.? ?
73 Tom
|
Thanks, Tom!
?
I am encouraged to know I should be OK with the 3.5V to the RX. As I can increase my TX output to 20 watts, that should make the RX even happier by cutting off a bit more signal than 10 watts.
?
As I'm not overly excited about making the bias changes you mentioned, I think I'll wrap it all back up and enjoy what's left of Novice Rig Roundup!
?
Also, I do run a Drake low pass filter in line after the TR switch.? I probably have the world's biggest collection of low pass filters, so it is good to get some use out of at least one of them.
?
I am so happy you took the time to comment here, Tom.? Thanks again.
?
73,
Jeff
W8KZW
|
The capacitors will not be perfect, they will have leakage. Usually it is a slow-charge leakage. Some years ago, probably the 1980s when I was doing a QSK switch for Heathkit, I looked at the Johnson TR switch. One thing is it puts significant harmonics on the feedline. Anything coupled to the line that clips, unless through a low pass or bandpass filter or properly buffered, will back feed harmonics into the line.? Do not expect this switch to cut off signal to the receiver into fractional volt levels. It cannot do that unless pass through good signals are limited in level, and that will cause increased IMD.? ? ? You said:
? About 10 watts into the TX jack and then on to a 50Ω dummy load from the Antenna jack
? Yields about 9.8 Vpp / 3.5 Vrms? across 50Ω into my scope (thankfully not my receiver)
? 3.5V is only 1/4 watt.? That is perfectly fine on old tube radios. Many solid state radios will take that.? It is unlikely you can change a few simple parts and make this work much different. It has to rectify in the first grid to develop cut off bias.? You might try a hard fixed cathode bias on the second cathode instead of? the cathode resistor. The cathode resistor tends to keep the second stage in conduction. As the cathode current decreases so does the cut off bias on that stage. If you used a resistor from HV and a Zener and held the cathode at a steady positive voltage the rectified negative grid voltage from the first stage would have an easier time getting the second stage into hard cut off.? Looking at the characteristic curves of the 6BL7 and guessing you have 250V anode, you need a net grid bias of -30V to cut the tube off.? You aren't going to get that without some circuitry assistance.? ? If the cathode bias was +10 V fixed you would need an additional -20 on the grid to cut the tube off. This is all just wild guesses in numbers but it is the general idea. Effective tube bias would be negative grid voltage differential to positive cathode fixed bias (even when cut off), so if you had +15 on the cathode and -15 on the grid you would have an effective bias of 30 volts.? The problem using a fixed cathode resistor in both stages is as the plate current drops from adding negative grid bias, the cathode positive goes away.? ?
|
Re: WTB - Johnson Signal Sentry
Hello Mike. I have one but have never tried to connect it.? There are a few little dings in the paint, but overall, it looks pretty good.? I can send a few photos if you like.
73, Russ. KW6T
I am looking for a Johnson Signal Sentry, Part No. 250-25.
?
Thanks!
Mike Harmon, WB0LDJ
mharmon at att dot net
|
Re: Free for USPS Postage, Valiant 1 panel meter
toggle quoted message
Show quoted text
Hello ?? Free for USPS Postage, probably Medium Flat rate box, to the lower 48.Insured. Let us know how much insurance you need for this meter.
We use lots of bubble wrap !!
This meter is not tested. Known Issues: Top edge of the movement housing has been chipped ( someone tried to remove the meter cover with a crowbar). ??? Movement SEEMS free needle movement but, as noted, not tested full scale.
Photo available
Thank You
Ashley
?
?
Thank You
Kiss-Electronics
Ms Ashley Hall
183 N 5th PL.
Cornelius, Oregon
97113
?
?
W7DUZ
?
?
On Wednesday, January 1, 2025 at 05:30:47 AM PST, Group Notification < [email protected]> wrote:
|
Re: Free for USPS Postage, Valiant 1 panel meter
Hello ?? Free for USPS Postage, probably Medium Flat rate box, to the lower 48.Insured. Let us know how much insurance you need for this meter.
We use lots of bubble wrap !!
This meter is not tested. Known Issues: Top edge of the movement housing has been chipped ( someone tried to remove the meter cover with a crowbar). ??? Movement SEEMS free needle movement but, as noted, not tested full scale.
Photo available
Thank You
Ashley
?
?
Thank You
Kiss-Electronics
Ms Ashley Hall
183 N 5th PL.
Cornelius, Oregon
97113
?
?
W7DUZ
?
?
|
Update:
?
The output of the TR switch to the receiver is a bit more manageable driving it with 30 watts (see photo) than with the 10 watts I ran in my previous post:
?
?
Assuming the maximum safe input to my tube-type receiver is +10 dBm, now -13 dBm should be OK.
?
But I was hoping to use my TR switch with my homebrew 10W rig. Am I wrong to think that increasing R1 would move the bias to drive V1 to turn off output to the receiver at a lower transmit power level?
?
?
Jeff
?
?
|
WTB - Johnson Signal Sentry
I am looking for a Johnson Signal Sentry, Part No. 250-25.
?
Thanks!
Mike Harmon, WB0LDJ
mharmon at att dot net
|
Mike Langner
Floyd - K8AC
Russ Williams