Wednesday, April 25, 2012

Johnson Viking II finally on the air

It’s been a long time since I’ve updated my experience with getting my Johnson Viking II on the air. It is working now and I have been enjoying it on the crystal controlled frequencies of 3.875 and 3.885 with just a little over 100 watts output on AM. After several years of having only a 25 watt low-level AM signal from either my Yaesu FT-857 or FT-450 I was quite excited to have a “proper” plate modulated rig on the air. But after a few nights on AM I discovered nearly everyone else (at least the ones with an armchair copy signal) were running full legal limit on AM – which is about 375 watt! Just to clarify, that equates to a 1,500 PEP linear amplifier. So, again, I have the desire to further improve my signal but for now, I must be content with the 100 watt Viking II.

So here’s how it went.

Even before I left the Orlando Hamfest with my $50 Viking II transmitter I went over to the table of one of the vacuum tube dealers seeking two 6146s to fill the empty PA tube sockets.

http://www.esrcvacuumtubes.com/index.html

My new friend Jeff Crovelli was nearby to remind me there is a difference between 6146 and 6146A tubes and the later 6146B tubes. You would think you’d want the most recent model but in the case of these 1950s era transmitters it is my understanding the plain 6146 or 6146A tube is much preferred to the newer B model.

There is a comprehensive discussion of the reasons here.

www.n6wk.com/kenwood/The_6146_Family_of_Tubes-1.doc

The only difference between the 6146 and the 6146A is the type of filament. The 6146A was developed by RCA and is called a "dark heater". The two types can be mixed in use. The 8298 is the same as the 6146A. It cannot be interchanged with the 6146B as it has different bias requirements, inter electrode capacitances, etc.

Friend Jeff also informed me I had a kit built radio instead of a factory built radio. He knew because the tube sockets and all of the hardware were mounted with tiny nuts and bolts instead of rivets. I think I like that because if I have to remove something from the chassis it will be much easier than drilling out tube socket rivets

Anytime you bring an old radio into the shack there is a powerful urge to immediately plug it in and turn it on. And for the days and weeks this Viking II sat inverted on the bench I admit to coming so close to doing that – just to see if it would play. I even read several discussions on the AM bulletin boards that suggested performing a wholesale capacitor replacement before powering up an old radio was overkill. Then I saw pictures of how a ruptured electrolytic capacitor can just ruin the inside of an otherwise clean chassis.

So, I waited.

I made a list of all the electrolytic capacitors in the radio and emailed it to the people at Just Radios.

http://www.justradios.com/

Remember, I have never repaired a non-working radio in my life. So what would have taken a qualified technician a few hours to perform, I took days to read and research. I described what I was intending to do and let the people at Just Radios fill the order with their recommendations. There were a few instances where the replacement capacitor was a higher voltage rating than the original. That’s OK – and even preferred.

In a couple of days a pouch of capacitors arrived. It was time to go to work. The first thing I discovered was that my 55 year old eyes were not nearly as good as I remember as a teenager so a handheld magnifying glass has become an added tool in my bag.

The Viking II transmitter chassis is spacious by comparison to any modern rig but for me, as a first timer, there were places that were not easy for me to access with a soldering iron and needle nose pliers. Trying to get to a terminal strip with multiple component leads and remove only a single capacitor lead was hard for me. Soon I decided to just cut the capacitor out of the circuit close to the component, leaving most of the old wire leads still nicely soldered to the terminal strip. Then I only needed to twist a loop in the old lead and attach the new capacitor to the old leads.

This is probably not what the purist would do it but it worked for me.

Pretty soon I had replaced all but the most hard to access capacitors. In fact, there are three I still have not replaced.

I spent a lot of time staring into the chassis looking for anything that didn’t look right. It was then I found a wire that had broken from a terminal strip and was laying, shorted to the chassis, under the big HV oil-filled electrolytic. I’m really glad to have found that because there would have been, most certainly, some fireworks.

Once I was satisfied I’d done all that I could it was time to light it up with 120 volts, 60 cycles, AC.

One of the tools I am glad to own is a big, heavy Variac that I can use to slowly increase the line voltage from zero to 120 volts.

I had read that it was desirable to slowly heat up a radio that had not been energized for years – maybe decades. But I never knew if that meant hours or days. So I plugged the radio in to the Variac and slowly turned to knob to about 20 volts.

In some of my research I read about a simple test bench where the author had a milliamp meter inline between the Variac and the radio. With knowledge of what the particular radio’s line fuse was rated you could watch the increasing current as you ramped up the voltage. If the radio began to draw current approaching the fuse rating you could back it down and search for the problem before you actually burned something up.

With a keen sense of smell I watched and waited for any signs of smoke. So far, so good. I probably could have safely just ramped the voltage on up but I remembered all those times when I had waited. A few more hours would not hurt.

I began to make some safety checks, measuring the AC voltage on the cabinet of the transmitter. I measured zero voltage between the chassis and earth ground but a Hammerlund HQ129X receiver I had been working had almost 40 volts on the chassis! Likely the result of a leaky bypass capacitor. With a non polarized two wire plug I knew there was the potential for a dangerous situation. I’ll change out that power cord very soon but I always have a good earth ground to all of my radios.

Finally, after a slow all day warm-up I had the transmitter up to 110 volts. I work for an electric utility company and know the standard AC line voltage at the meter socket today is about 120 volts and could be a few volts higher. But in the 1950s the AC voltage standard was closer to 110 or 115 volts. We all know that a conventional incandescent light bulb will last a whole lot longer if you dim it slightly (run it at 115 volts instead of 120). Knowing the scarcity of certain vacuum tubes I have chosen to keep the Variac inline all the time and run the radios at 110 volts. This reduces the filament voltage by a slight amount and, hopefully, will prolong their life.

Using my Fluke 87 digital voltmeter I measured every voltage I could find under the chassis and didn’t see anything out of order.

Now, for the big moment. It was time to flip on the high voltage. On the Viking II the high voltage power supply produces about 865 volts. If there was a bad capacitor we were about to find it. I connected my air cooled dummy load, reached for the safety glasses and quickly flipped the switch on and back off.

No smoke. No burned fuses. So far, so good.

By now I had already studied the operator manual from cover to cover so the process of loading the transmitter on 3.885 MHz was pretty much a non event.

I am grateful to have been introduced to amateur radio in 1973 when every ham had to learn how to peak the exciter, set grid drive then dip and load the PA to the specified plate current.

I was, by now, feeling pretty proud of my old $50 transmitter. The next step was to connect a microphone and see if it would transmit audio.

During all of my research on Johnson transmitter restorations I learned of people who had to spend much time and effort undoing modifications of a previous owner. The most damaging were those that involved extra holes in the chassis or changing plugs. That said, I determined that I would keep the original microphone jack on the Viking II and order a mating plug. But in the mean time, a couple of clip leads and I had a D-104 connected and verified my radio would transmit audio. Pretty good sounding audio actually!

Up until this point I had resolved to do as little as possible, both mechanically and cosmetically, until I could get the transmitter on the air. If it worked and stood up to a few weeks of frequent use, then I would get serious about other elements of the restoration.

It was finally time to bring the radio into the house. This monster weighs about 85 pounds and it is easy to see why the radios are called boatanchors.

I placed the Viking II atop my HQ 129X and with my two 80 meter crystals I was finally on the air with a “proper” plate modulated rig. Cosmetically, this rig looks a little rough but electrically it appears to be operating within its specifications. I’ve not made any modifications and at the moment I plan to keep it is its stock condition unless I decide to make some audio improvements.

I have come to really like this transmitter. People frequently use the term “built like a tank” but that seems to best describe the construction of this radio. I’ve been told that Johnson purchased a lot of surplus WWII components such as modulation transformers etc. and some of those parts became the basis for their transmitters of that era.

Now that I know it works, I have removed it from the ham shack and will begin a more in depth restoration. I plan to check all of the resistor values then do a thorough cleaning of the chassis. I don’t feel comfortable removing the transformers and other components. I will mask and repaint the transformers. I’ll also clean and polish the knobs. The front panel has what looks like very fine pock marks on the paint. As much as I would love to have a new silk screened panel I am going to experiment with cleaning with some 0000 steel wool followed by a rubbing compound and then a paste wax.

Don’t hold me to that. I will try it in a small area first. I am reminded of the physician’s creed, “First, do no harm.”

Here are some of the areas of concern that I will address.

There are two 807 modulator tubes. During my initial bench testing I observed one of the two modulators not lit. I found this to be due to a loose pin on the tube base (not the socket). There is probably no way to fix that other than a replacement tube. I touched it with a soldering iron for a temporary fix.

There is a front panel control that switches in 160 meters. The front panel control operates the switch with a loop of dial cord. The switch is stiff and frozen and it appears the dial cord might break if I force it. Inasmuch as I may never operate 160 meters I have left it alone for now. Remember, “First do no harm.”

The next most obvious need is an external VFO. These radios were crystal controlled and at the current price for FT243 crystals I could buy a Johnson VFO for the price of a full rack of crystals.

That’s about it. My $50 radio has taught me a lot. With two new 6146s and a hand full of capacitors and two new crystals I’ve been able to get on the air on 80 meters AM and have really gained a high degree of confidence that I can troubleshoot and repair simple radio transmitters.

It’s a good feeling!



Sunday, July 17, 2011

Restoration of a Johnson Viking II -- My first project.

After years of surfing the web and admiring pictures of beautifully restored boatanchor classics I now find myself with a Johnson Viking II waiting to be returned to the AM airwaves.

The transmitter appears to be physically complete and unmodified. There are no holes in the chassis or panel and all of the knobs are in place. The only part missing is the perforated metal top.

I am not an electrical engineer or a technician. I have never repaired a radio from the component level. I can solder, clean a chassis, install connectors, build antennas and other basic stuff and I read insatiably.

But, I have always been only an "appliance operator". I have a working knowledge of electronics. I use a Fluke 87 multi-meter, a Bird wattmeter and a frequency counter and I've have played only casually with an oscilloscope to monitor modulation. I've never worked at the component level with a radio.

During my teenage years I was a radio disk jockey for a small-market station and worked under the tutelage of a First-Class broadcast engineer. At age 16 I was down at the transmitter shack assisting with a Proof of Performance and learned much about the insides of a Gates BC-1J (1000 watts with 833A's). Just as a sidebar to this story, when the modulation transformer on the Gates transmitter failed, I ran home and robbed the transformer from my BC-610. That got WBLO back on the air, at least for a few days, before my BC-610 transformer also failed.

At the end of my teenage years I let a lot of great old radios slip thru my hands, not knowing that one day I'd give just about anything to have them all back. I had an R-390A receiver, A National NC 300, a BC-348 receiver, A BC-610 transmitter, now minus a modulation transformer, a Globe King 500, a Johnson Valiant transmitter and a host of other radios.

Dang it, I sure wish I had any one of those back.

I was first licensed at 15 as a Novice and then joined Army MARS (That's why I had all the old AM gear). Now at age 54 I have a rekindled interest in the hobby. I listen to the AM guys on 3.885 and occasionally when the band is quiet, I have a few short QSO with 25 watts coming from a Yaseu FT-450. But I dream of a good solid plate modulated AM signal.

I know this Viking II is still not going to produce a powerhouse signal on 80 meters but it only cost me $50 at the Orlando, FL hamfest and that's what I have for the moment. It doesn't look too challenging to work on and I think it will be a good "experience rig" to learn some restoration techniques.


So, here's where I am at present.

1. I've resisted the urge to plug the rig in - even though I have a Variac - I've read enough to believe trying to heat it up would likely result is an exploded capacitor then I'd have a real mess to clean up.

2. I have an original manual

3. I've made a shopping list of all of the paper/electrolytic capacitors.

4. I've made no efforts yet to clean the chassis or to lubricate the shafts of the various controls. Some are a little stiff. One concern is the 160 meter In/Out control that uses dial cord to operate a ceramic wafer switch. I'm afraid it would not take much to break that cord and don't want to add restringing the dial cord to my list of "must do" items.

I would appreciate any advice on changing out capacitors. I haven't ordered yet but I have found most of then at http://www.justradios.com/

But assuming that is a success, what is the best advice of chassis cleaning. I don't want to do more harm than good. I was thinking of DeoXIT for the controls and tube sockets.

So that's where I stand for now. Here are a few pictures, actually a LOT of pictures. https://markbolton.smugmug.com/Johnson-Viking-II-Project/i-f73gSHj/A
I'd sure appreciate all advice and assistance.

Sunday, November 14, 2010

Hot new Wouxon HT from China

After several years of heavy use my Yaesu VX5R finally bit the dust a few months ago and I find myself missing not having a dual band HT. I have, for a few months, used a couple of single band portables that I had. One for VHF, the other UHF. But it was rather cumbersome carrying around two radios. I looked thru the catalogs and was faced with all of the Yaesu choices. What I really wanted was an Icom D-STAR portable but was not quite ready to pay that much of a premium to have my voice transmitted with zeros and ones rather than good old analog.

Enter my good friend Russ who always has the latest techie toys. Russ, having recently returned from the Lawrenceville hamfest, had just ordered a hot little dual band HT being sold at the hamfest for $109. It is a Wouxon – a Chinese brand – that may just give the Japanese brands a run for their money. Truth is, a growing number of the lower priced “name brand” radios are already being built in China.

I’ll be honest, I am not a Wal-Mart shopper, and I really don’t like the current US trade situation with China. I am a strong shop local, buy American supporter. That said, I’ve fallen victim to the sweetness of a very low price for an apparently great little radio. I trust my friend Russ who gave me several instances where the Wouxon outperformed one of the major brand radios at the demo table in Lawrenceville.

So, I’ve done my research, read all the reviews, and in a moment of weakness, I have sent $109 to a US distributor for the Wouxon KG-UVD2 dual band portable.

http://www.wouxun.us

I recommend this gentleman and his website as a good place to shop. He is a “real live person” in North Carolina who will personally answer your e-mail (sometimes is less than a half-hour). Ed reminds his shoppers that all his radios are FCC Type Certified in the USA and warns to beware of dealers selling non certified radios.

It appears to me the Wouxon is manufactured to be sold internationally in both commercial and amateur markets. It is made with a variety of frequency ranges (basically the same radio, just with different frequency bands enabled). And, even before you ask, yes, there is software to make your radio transmit on those other bands.

I won’t make too many more claims inasmuch as I have not received my radio yet but others seem to feel their radio has a pretty hot receiver. I’m anxious to see how it handles intermod in an RF rich environment. I have read of a man who is using these little radios as remote receivers for a repeater!

One think that is universally recommended is that you download the free software to program your new radio from your computer. And, you will be pleased to know that the required programming cable costs only $18.95. And, it is available as a DB-9 or a USB cable. Remember when Kenwood wanted to charge nearly $80 for their cable for the singlebander TM271A? And they boosted their software was also free.

In fact, all of the Wouxon accessories and quite inexpensive. It does not appear the manufacturer is selling you a low priced radio and making up the difference in overpriced accessories.

I have already installed the programming software – actually not an installation at all, just a simple .EXE file to run. If you have used commercial Motorola software to program radios you will find this to be very similar. If you haven’t, don’t worry, it is very easy. But it just reminds me that Wouxon is probably marketing this radio to the commercial market as much or more than the smaller amateur radio market.

So check back here in a few days – Hopefully I’ll have my radio by then and can post an update.

Sunday, November 8, 2009

Unwinding at Winshape Retreat

I'm embarrassed to see how long it has been since I have updated this blog. But I have been traveling a good bit lately and have just let the time slip away.

Last week I had the opportunity to spend a couple of nights on the campus of Berry College (it is a 26,000 acre campus!) near Rome , GA. More specifically, I was at a conference at WinShape Retreat, a facility that was formally a 70 year old working dairy farm. Students who could not afford tuition at Berry College could work and live on the daily farm and work their way thru school.

But now the barns and milk houses have been converted into very spacious hotel rooms and conference facilities. There is an elaborate multi-media conference theatre and a dining room (formally the milking barn) that even serves cold milk in the traditional glass bottles.

The facility was make possible in part by a most wonderful gentleman, Truit Cathy of Atlanta. You may know him as the founder of Chick-Fil-A.

If your organization, church or just a group of friends are looking for a truly out of the way place to gather and enjoy a family reunion or perhaps some type of church related event, I highly recommend this place. One thing I might mention. There are no televisions, no phones in the rooms and, unless you bring your own aircard -- there is no Wi-Fi except in the conference center. And you know, I didn't miss it one bit.

If you enjoy astronomy you will also enjoy this setting. You are on the top of Mt. Berry when there are no street lights, and very little outdoor lighting of any type. I was fortunate enough to be there on two absolutely perfectly clear nights and I saw the milky way for the first time in a very long while.

Accommodations are very reasonable. All meals are included, even the pastry and coffee bar is open and free. The first evening we took a hayride and toured the campus of Berry College. There are hundreds (I do not exaggerate) of deer roaming the campus. Because we were an electric utility group, we also toured a nearby hydroelectric power plant. The second night we just gathered around the outdoor fireplace and roasted smores. (One person was appointed to keep their PDA connected so that we could get the football scores).

For more details visit the site. http://www.winshaperetreat.org/

Saturday, August 15, 2009

Trying to Reason with Hurricane Season

With apologies to Jimmy Buffett -- It looks like it is finally showtime in the Atlantic.

Many of you know that I am an avid storm watcher -- so long as I can keep a couple of hundred miles as a "safety zone" between me and the storm. I've spent way too many hours surfing the Internet looking for new bits of information on hurricanes and the forecast models. I have finally settling on one site that gives me just about everything I want and some of the coolest graphics I've seen.

Go to www.stormpulse.com

Then look on the upper right corner and click the "Forecast Tracks" button. There is much to explore with this site -- just hover over the various items and enjoy.

One other site that has nice maps, especially when the storm is making landfall, is

www.skeetobiteweather.com

So, stock up on the canned goods, gas up the generator and charge up the batteries 'cause the "big wind" is gonna' blow -- maybe.

Friday, August 7, 2009

52nd Scouting Jamboree on the Air

One of the great Scouting and Amateur Radio events each year is the Scouting Jamboree on the Air (JOTA). JOTA is an international Scouting activity held annually on the third full weekend in October. The event was first held in conjunction with the fiftieth anniversary of Scouting in 1957 and is now considered the largest event scheduled by the World Organization of the Scouting Movement (WOSM). Amateur radio operators from all over the world participate with over 500,000 Scouts to teach them about radio and to assist them to contact their fellow Scouts by means of amateur radio and, since 2004, by Echolink. Scouts are also encouraged to exchange QSL cards. This provides the Scouts with a means of learning about fellow Scouts from around the world. It is an adjunct to the World Scout Jamboree. The Coastal Empire Council JOTA will be October 17th from 10:00 a.m. till 6:00 p.m. at the Mighty Eighth Air Force Museum at Pooler.

Thursday, August 6, 2009

Getting Recharged at Amelia Island

One of my favorite places here on the coast is Amelila Island Plantation. Wendy, Nicholas and I had the opportunity to spend a few days there last week. It was mostly work for me but Nicholas and Wendy got to play. The trip was a little less pleasant due to four separate electric power outages -- two in the same night! But we just opened the doors and slept under the moonlight till sometime after 1:00 a.m. when we were awaken by the TV blaring and all the room lights coming on.
There is a quaint little lighthouse there that I'd like to see some of my lighthouse buddies activate one weekend as a special events station.