The AM Forum

Been shopping locally for a first AM station and ran across a gent willing to do some trading. I have a choice to make now. The transmitters available are: Gonset GSB-100 with the GSB-101 amp, B&W 5100, or Johnson Viking II.

All are in working condition, but I am not aware of what, if any, mods or repairs have been done to any of the transmitters. I am not real tech savvy (yet), so simpler and easier to work on is a consideration. Also I'd like to go with a unit that has the most parts still available - no unobtanium tubes, for example. I'm handy with a soldering station, have multi meters (digital and analog), and an RF probe I built, but that's the extent of my test equipment. Have local guys with the know how, and test equipment, willing to help and teach, so I'm not totally on my own here.

Any opinions? Thanks in advance.

Doug N3PDT

afaik, the Gonset isn't plate modulated... but you get the amp...

any of the three will work, imo.

I'd personally prefer the B&W, but that's mostly looks.
I think the Johnson is built a little better, but you need the external VFO... and I like the silver case on the "II" series...

if it's all the same price and you don't need an SSB amp for the higher bands, then take ur pick! :D

       _-_-bear

Get the V-II, you won't regret it. I sold mine and now wish I had kept it. Built like a tank and easy to work on 100w class tx. Just remember, you'll need either xtals or a VFO. Be sure to check the roller inductor very well for good roller spring tension and no burn marks from arcing. Have fun!

73, Phil   

Get the Viking II. Its is a simple 100 watt rig with lots of room inside to work around, many parts still available via hamfest or parts suppliers like Allied, Mouser, Newark, etc... 6146's are still easy to get and plentiful. Also, many here have posted mod's to the VII and have  alot of experience with that rig, so getting expert help is no problem.
Gonset and B&W have added complications of having a built in VFO. A VII need an external VFO, but you can get a Heathkit VF-1 and wire the octal socket to fit the VII, which makes this rig even more versitile.

Mike, W2ZE

Get the Viking 2..Astabula Bill said it was the best because you could have it up on it side and work on it during a QSO...Lots of room to work.... easy circuits...lots of parts around...The B and W 5100 is modular chassis...modulator and RF decks on their  own chassis .....It not bad either...Viking is 6146's x 807's   B and W 6146's x6146's  Good Luck....

Wow. Thanks for the quick responses.

Looks like I'm trading some Kenwood hybrid gear, plus some odds and ends I don't use anymore, for the Viking II, a Heathkit VFO, a box full of a disassembled Viking VFO, and a National NC300 receiver. I think I "did good".

I might be just a bit excited about this...

The Gonset is a phasing rig and the AM sounds real good BUT its only about 15W out from a single 6DQ5. The amp will boost that to a 100-125W carrier (400-500W PEP) which can be done with the V II but you get SSB and a stable VFO thrown in but no 160. Power xfmr is weak so replace all electrolytics before turning on.

The V II needs some serious audio work to sound good as it is very restricted and not capable of 100% modulation at even 100W out without serious distortion. Lots of online details and support as so many still exist. Same caveat about ALL the electrolytics.

Pass the of whats all available to others along with contact info.

Carl

Thanks Carl. I will let him know there is interest here. Not sure how much he wants to unload at this point. This is one of those "happy to help you get you on the air" deals as much as anything.

I am going to suggest you look very close at the B&W.  It is quality built and will give you the honest 100 watts.  The real plus for it is the internal VFO which is the most stable of any tube rig I have ever used.    Do be careful to inspect any of them for modifications as the CB crowd loved the Johnson and B&W.

You will like the modular construction if you every need to make repairs and you won't have to do a lot of modification to have good audio like you will on the Johnson.  The Gonset is not a player in the same league as the other two.

All this is provided they are in good, unmodified condition or can be made that way easily.

Wasnt it the 5100 that was a drifter and the 5100B fixed that and some other problems?  Or a I thinking of something else?

Carl

I have had a couple of both and none drifted that much Carl.  The downside it all the 6AQ5s in the multiplier chain.  All that is dependent on the fact some CB op didn't modify the VFO to cover the bottom of the CB band.  In that case, all bets are off.

For your 1st transmitter I would get the Viking II,for all the reasons stated above then I would purchase Electric Radio
Magazine  issues 110,111 and 112,articles written by K6AD and study them,great info.If you do the level one mods in # 110,you will have a nice sounding rig.The B&W
will sound better out of the box but there is so much more info and parts around for the viker.

dale/ka5who

I modified my V-II CDC around those ER articles with a few differences. Came out fine in distortion and other tests and on the air reports. Besides the electrolytics and paper caps I also replaced the HV oil cap as it was running too warm. A pair of 100uF/450V in series with 100K 3W equalizers improved the dynamic regulation a bit.

Started to do it on my V-I also but been distracted by paying jobs ;D

Jim, I had a 5100 a few years ago used mostly on 10M where it did drift for a good half hour + but that is an extreme test. The CDC came along and I sold the 5100 off and picked up a 32V2 shortly after.

Carl

Thanks Dale,

Three reprints from Electric RAdio on the way. Subscription added to Christmas list.

Picking up transmitter and receiver in about an hour.

Doug

My vote is for Viking.

C

Sounds good Doug keep us informed on what is going on and or questions.There is a wealth of knowledge here.

dale/ka5who

They're home! First, some photos of the Viking II. Other pieces to be photographed later. Face and case are okay, but not gorgeous. It is missing the top cover. Inside is clean, PTT mod done, maybe some audio mods, and electrolytics replaced. Not a beauty queen, but solid and clean.

Top view-nice and clean:

(http://www.mygoodpix.com/Other/Johnson-Viking-II/i-KVr3x8s/0/L/Top-L.jpg)

Underside (already re-capped!):

(http://www.mygoodpix.com/Other/Johnson-Viking-II/i-6Fm9QCf/0/L/Underneath-L.jpg)
Unidentified add-on - previous owner didn't know either:

(http://www.mygoodpix.com/Other/Johnson-Viking-II/i-qCFSf8Q/0/L/what%20module%20is%20this-L.jpg)

Link to gallery: http://www.mygoodpix.com/Other/Johnson-Viking-II/27174289_MXR8v3

Also got the Heathkit VFO, but haven't determined if it's been wired for the Viking II. It has both an octal plug and another lead that is supposed to be able to be used in a crystal socket, but no crystal "blank" for that use. No crystals either.

NC300 receiver is still the garage getting cleaned up a bit. It will need some deeper cleaning, as there's a pretty serious film on the chassis, but it's reportedly working properly. Will hook up the receiver later and listen.

No antenna relay yet, and really need to research that further. Local shop had a Johnson electronic T-R. I'll stop in and see if it's still there tomorrow. I will be using the same antenna for transmit and receive for now.

So, first dumb question: Until I get a relay, is it okay to just switch between the units manually with a 2:1 antenna switch?

Grid block keying mod from Johnson.

Rig look like a real keeper.

The NC-300, unless already done, will be loaded with paper caps in plastic and out of tolerance resistors.

Carl

Rig looks like a good one,I see a new Hammond Driver transformer,that is good.
Yes you could use a ant switch for now to go between receiver and transmitter also use the xmit, receive switch on the front of the NC-300 to mute the receiver on xmit No that brown wire does not go to oscillator vari,that looks wired right from what I can see,not sure where that 
wire is from.Do you have the manuals? If not go to The Boat Anchor Manual Archive,
BAMA and download both the viking and NC-300 manuals for free.

Daler/ka5who

I have the Viking II and NC-300 just like yours but I have the Johnson 122 VFO.  Really drifty for the first 45 minutes or so but it will settle down.

The VII is a workhorse.  I only replaced the electrolytics and the coupling caps in the audio circuit and with an EV664 mike, I have been getting decent audio reports.  Very easy to work on.  Try to find a top cover if you can.  The VF-1 will work great once you verify it's wired up correctly for the VII.  It's output connects via a piece of coax into a PL-259 on the back of the VII, not into a crystal socket.

The NC-300 works OK, but will need some resistors and caps replaced over the winter.  Nice audio too.

Get the manuals, READ the manuals and have a good time with those great boat anchors.

 

The 122 and VF-1 benefit from switching to a 6AH6, drift drops way down; also works in various Globes.

Several have reported that changing mica caps associated with the 40M range in the 122 also reduce drift.
Another hint was to change to a 105V VR tube and increase the associated dropping resistor.

Id also tighten all ground lugs and other hardware to minimize the Hallicrafter sound when you tap the table ::)

Carl

I gotta try those changes.

Thanks!

U shoulda taken the B&W 5100. 

Maybe the next one.

You did well, Doug. Aside from the missing lid (put an ad in the Wanted section, should be easy to find a donor cabinet), it looks clean inside. The 5100 is a decent transmitter but more complex and troublesome than the Viking. Sounds like this might be your first AM transmitter, so the Johnson is the way to go. It's a great 'basic' transmitter that allows you a lot of latitude to change, repair, or otherwise learn on. Chances are you can pick up the 5100 later for a reasonable price. I passed one up for $125 a few years ago because I didn't want to haul it back to my car. They're neither rare or expensive, but very well made.

Wonder if what you traded was a set of Kenwood twins? They sound pretty decent on AM, though only 20 watts or so.

Hi Todd,

Thanks for the words of encouragement. Yep, I'm confident I made the right choice for a first vintage AM transmitter.

Incidentally, I made a post on a local ham radio email list that I had a Kenwood hybrid in good shape I'd like to trade for some vintage gear for AM and "boat anchor" CW operation. I was surprised at how many responses I got. What I traded was a TS-520s! Other guy was happy to get it and has reported back that he was having fun with it.

Still haven't put power to the transmitter yet. Today I scared up a Johnson VFO 122 and a NOS Advance coaxial relay. Traced the "brown wire" mentioned earlier, and it's unattached on both ends - apparently left over from a mod.

I'm at the point where I think I'm going to have one of my much more knowledgeable ham buddys come over and help and walk me through some of this before I tune up the Viking II. I'm unsure of the VFO wiring, still haven't figured all the mods in the transmitter, wondering what the toggle switch added to the VFO does, etc. We're going to spend some quality time with the schematics and a multi meter before proceeding.

Receiver works well. Having fun learning how to tweak it.

Dumb question for tonight: What kind of plug is used in the pair of ceramic sockets for driving the relay off the back of the Viking II?

I throw in for the Viking as well. I had one (a "I" actually, not a "II") and loved it. IIRC much of the TVI issues were fixed in the "II". Put its VFO back together and have fun!