Classic Radio Shootout: Clash of The Titans    

35 years later, the two top of the line vintage CB radios duke it out for overall best status. 

  

vs.

 

I've been going on and on for quite some time now talking about those "Dream Rigs" of the early 1970's.  Those legendary, almost mythical, high end radios which were elusive, ungodly expensive, and that which we all wished that we could own, if we could somehow hit the lottery, or a bag full of money would fall out of a Brinks truck in front of our houses.  The fact that few in our local CB crew owned one of these expensive premium rigs, led to all sorts of rumors about how great they were and what really cool things you could modify them to do.  Of course, without actual hands-on experience, most of this talk was based purely on hearsay and those stories tended to grow legs and expand beyond the realm of purely factual information.  This gave life to all sorts of rumor-based legends being created and proliferated around the local area.  Exaggerated claims about unbeatable adjacent channel rejection (A big deal back then when practically every channel was full of people talking), superior audio, and superior receiver sensitivity were all bandied about.  Invariably, the talk started to focus on which one of the two top rigs was actually the better performer, with people lining up to take sides, in a rivalry strangely reminiscent of the "Ford vs. Chevy" debates among car enthusiasts.  It was sometimes comical to hear all these opinions and heated debates flying around the channels regarding one of these radios, coming from people who had never even seen one of these high dollar radios in person, let alone actually operated one.  If you haven't figured it out yet, I'm talking about the Browning Golden Eagle Mark III, and the Tram D201 here, as these two were arguably the top of the line CB radios out of all the popular rigs of the mid 70's, with the highest price tags to match.  One didn't have to listen around the channels long before that telltale "ping" of the Browning Golden Eagle would wake up a channel, or the punch and warmth of either the Browning's, or Tram's rich tube audio (on an unamplified mic!) would stand out from the rest of the pack in the distance.  Anyone with an experienced radio ear could easily tell the difference between the run of the mill CB and one of these larger than life giants.  They were the last of a dying breed.  The writing was on the wall.  Solid state rigs had taken over in popularity, and tube radios were rapidly becoming "yesterday's technology".  But the engineers at Browning and Tram were not about to go out without a fight, and they set out to prove that while solid state was certainly more convenient to design radios around, and printed circuits were certainly cheaper to mass produce, to truly experience the best quality money can buy, meant that you still had to rely on tubes.  And since it was far more labor intensive to assemble a tube-type radio, especially one which still used point-point wiring, like the Browning, the price tag was quite a bit higher than a comparable solid state radio.  So for these radios to live up to that $800+ price tag, they'd better deliver something special.  And from all anecdotal accounts they did.  Unfortunately, I could never afford to own one of these radios back then, to witness first hand whether they were truly worth the accolades and their high price tag.  35 years have gone by and I never did have the opportunity to own, work on, or even see one of these rigs in the flesh -- until now.   In the last year or so, I've become the proud owner of both a Tram D201 and a Browning Eagle MK III (and have worked on several more for other collectors).  So I thought, hey, here's an opportunity to finally pit these two legendary giants against each other in a no-holds-barred, winner-take-all shootout, and  settle the eternal question once and for all, of which radio was the real king of the 1970's Citizen's Band airwaves.

Of course, for any contest to be fair, it has to have a few ground rules and this one will be no different.  I've decided that the rules will be relatively simple but fair.  I will conduct the comparison based on 4 criteria: Features, Technology, Objective (on the bench) Performance testing, and last but not least, Subjective On-Air testing based on operator satisfaction and pleasure, with a focus on ease of operation and receiver quality, as well as the feedback from other operators on the overall transmit audio quality.  I could really go overboard and assign a point value to each specific feature within a category and the rig with the most points wins.  But I think I'll just test each category on a win/lose basis and assign a single point value to each of the 4 criteria.  Since how a radio performs on the bench is probably worth more than a subjective opinion, the point weighting will likely be greater for the performance test.

So enough with the boring details, now let's get acquainted with the contestants and list their features.

"In this corner......"

First up is the Tram D201

The Tram is equipped with the usual standard features, like Volume, Squelch, Mode switch, Receiver Tone, Noise Blanker, S/RF/SWR Meter, and R.F. Gain. The more "premium" features on this radio are as follows, starting with the variable receiver Tuner in addition to the regular crystal Channel Selector. The variable tuner allows reception of frequencies up to 27.550 Mhz.  Another Tram exclusive, was the Transmit Tone Control (TTC) which changed the frequency response of the transmit audio to match the voice and microphone characteristics of the operator.  Finally there is an SWR bridge.  All of this was housed in a rather large cabinet with a hinged top and finished wooden end pieces, which combined a nice blend of technological prowess along with the subtle aesthetics of polished wood furniture.

Next, we introduce the Browning Golden Eagle Mark III

The Browning is a unique two piece design, with the transmitter and receiver housed in separate independent cabinets, which were finished with a steel cover laminated with a simulated veneer wood-look. The transmitter was a straight-up AM/SSB 23 channel crystal controlled design, with a meter for modulation, plate current, and SWR. A neon bulb indicates which mode you're set to.  A variable "VFO" (clarifier) allows a small (+/- 800 hz) shift in transmit frequency for SSB operation. The receiver is strictly a variable tuner, with a "Bandspread" clarifier to assist tuning in SSB.  In the later models, there's a switch which selects two ranges for the tuner to tune, with the normal 23 channel CB band on one, and an "HF" band of channels starting at 27.285 up to 27.595 on the other. There is also a fixed crystal position, where you could presumably install a crystal for your home or some other frequently used channel to eliminate the need to tune it in with the tuner.  Other controls on the receiver included;  Volume, Squelch (which doubles as a ANL on/off switch), and R.F. Gain. The R.F. Gain control also doubles as a switchable AGC.  There is also a switch to control whether your audio comes out of the internal, or an external (or both) speaker.  The receiver also features a red "ON THE AIR" indicator which lights when the transmitter is keyed.

Now we move on to the head-head feature comparison:

Both the Tram and the Browning use odd style microphone jacks, which makes sharing mic's with other "lesser" brand radios a bit more difficult.  But this is not an insurmountable problem if you fabricate an adapter cable.  Further feature comparisons between the Tram and Browning reveal that the Browning is ideally set up for split frequency/mode operation.  Not that this happens very often, but you could conceivably set the transmitter to one channel (and mode) and the receiver to another and talk to another similarly equipped station.  An unmodified Tram D201 could also split frequency (but not mode), by utilizing its internal manual tuner.  But most people who own Trams opt to do the simple mod which enables the manual tuner to function as a VFO on transmit as well as receive, which negates the ability to do split frequency.  But the built-in VFO-on-Transmit mod is worth far more than the loss of split operation to most people.  

Both radios employ "S"-meter, R.F. output, and SWR meter functionality, although these functions are on separate meters on the Browning. The Browning also includes a modulation function on the transmitter.  Both radio's meters are large and easy to read, and both track receive signal strength fairly linearly, with each 1 "S" unit being very close to 6db through most of the normal range.

Both radios also worked well with high impedance unamplified microphones, making a preamplified mic unnecessary.  The Tram's Transmit Tone Control (TTC) makes operating with different microphones a breeze.  You can also adjust the TTC to compensate for different operator voice characteristics (I.E. Husband/Wife). The Tram comes equipped with an adjustable Noise Limiter and a switchable pulse-type Noise Blanker, while the Browning employs a simple ANL on/off switch function as a user controlled feature.  Both radio's noise limiters are fairly effective at reducing "static" type noise, although they do this at the expense of introducing a bit of distortion to the receive audio.

Operating on SSB is a bit more difficult on the Browning.  Since the transmitter and receiver are separate, they are not synced up frequency-wise, and when talking on SSB, someone has to tune to you and then you can tune to them.  On the plus side, you can adjust your receiver without moving the transmitter, which prevents the dreaded "walking the clarifier" syndrome, where everyone alternately touches up their clarifier to the other guy's signal, and they gradually move up or down the frequency.  The Tram works more like a typical radio on SSB, and was much easier to master quickly.  The clarifier sync's both receive and transmit, and when you tune to someone, they will hear you just fine.

So for a summary of the head to head comparison of the major features, it goes like this:

Ease to modify for out of band transmit operation: Tram

Split Frequency operation: Browning

Range of manual tuner: Browning (by about 45 Khz)

Ease of use on SSB: Tram

Microphone flexibility: Tram

Noise Reduction: Tram

Metering: Browning

Overall winner: Tram

 

On to the technology comparisons:

 

Both the Browning and the Tram employ primarily tube circuits.  The Browning's receiver is powered 100% by pure tube active circuits. The Browning's transmitter is about 98% tubes with 3 transistors in the ALC/AMC circuit.  The Tram employs mostly tubes, but has some circuits (Primarily the frequency synthesizer, Noise Blanker, and balanced modulator) which employ solid state active devices (including an I.C. Noise Blanker detector).  The Browning uses straight-up point-point wiring, while the Tram utilizes (at least in the later models) printed circuit boards with interconnecting wiring harnesses.

The Browning, as mentioned before, utilizes a separate transmitter and receiver.  This separation necessitates the duplication of some circuits, which are normally shared in a transceiver (such as the power supply). In a few cases, some normally shared components were not duplicated, presumably to save on cost.  But I have to wonder how this affected overall performance.  Case in point is the SSB I.F. crystal or mechanical filter.  The Browning uses such a filter in the transmitter to shave off the undesired sideband for proper SSB transmission.  However, on most transceivers (including the Tram), the crystal SSB filter is also used on the receiver to provide superior selectivity and unwanted sideband rejection.  In the Browning's receiver, this narrow I.F. bandwidth is provided by successive stages of high "Q" tuned circuits.  Whether this works as well as a crystal filter will be revealed during the bench tests.

On the other hand, the Tram's receiver is a dual conversion equipped with a razor sharp SSB filter for SSB, and 455 Khz resonators or filters (depending on year of manufacture) for AM, to provide exceptional selectivity and adjacent channel rejection.  SSB detection on the Tram is accomplished by a true product detector, while the Browning employs a simpler BFO circuit.

The Browning uses a cascode pair of Nuvistor tubes in the front end, which is notoriously good at providing high receiver gain with low noise. The Tram similarly uses a cascode design, but elected to use a traditional glass dual triode 6BQ7 tube.

On the audio side, the Browning's receiver utilizes a 6AQ5 output tube, which is normally good for about 12 watts of plate dissipation.  On the transmit side, the modulator uses a slightly beefier 6BQ5 tube also good for about 12 watts plate dissipation. The Tram utilizes a single 6L6GC tube for both receive audio and transmit modulation. A bit more powerful at close to 30 watts plate dissipation, the 6L6 is more than up to the task for providing ample audio.

The transmitter final R.F. sections are pretty much the same story. The Browning uses a 12 watt dissipation 7558, while the Tram uses another 30 watt 6L6GC.

The one real sore spot in the Tram's circuitry is the two tube differential balanced S-meter amp. This circuit notoriously drifts, requiring frequent readjustment of the meter zero. The Browning's S-meter is more conventional and is typically more stable once the radio warms up.

The power supply design on the Tram is IMHO, another soft spot.  Rather than designing the power supply to generate multiple voltages for powering both the high power and low level tube circuits, Tram chose instead to run a single 410V supply and just resistor down to the required voltages. This results in a radio which generates a tremendous amount of heat and eventually causing more parts to fail over time.

 

Winner: This is a toss-up. The Tram's superior receiver filtering and audio power amp design is somewhat offset by the power supply issues, which, in all fairness, does not take away from the radio's performance, and only shows up years later (like now). The Browning's SSB operation is not as easy to use as the Tram's.  The Tram is capable of more power out on transmit, but both are capable of operating at FCC mandated power levels as of date of manufacture.

 

 

Here are the Bench Test numbers:

 

Receiver sensitivity- Tram .08uV Min AM & SSB. .2 uV for 6db S+N/N

                                Browning .04uV AM, .08uV SSB Min. .1uV for 6db S+N/N  

The Browning edged out the Tram in overall AM sensitivity. However the lack of a narrow SSB filter and product detector limited its SSB performance.

 

Adjacent Channel Rejection-  Tram 70db

                                               Browning: 65db

 

This was one of the most important receiver specs back in the mid 70's when the channels were spilling over with people. I seem to recall that both the Browning and Tram were factory spec'ed at 80 db.  My testing didn't show it to be that high. But the Tram's IF filters did give it a 5 db advantage.

 

Receiver Winner: AM- Browning,  SSB- Tram

 

 

Transmitter Power- Tram AM: 3 watts, SSB: 17 watts

                             Browning AM: 3.5 watts, SSB: 10 watts

 

AM Modulation- Tram: 100% (Modulation limiter functional)

                          Browning: 120% (Modulation limiter not functional)

 

Transmit Winner: No clear winner could be determined here

 

 

On-Air Subjective Performance Tests:

 

AM TX audio quality:

During a recent local Classic Radio Roundup, I put both the Tram and the Browning on an A/B switch, with the purpose of soliciting opinions on which rig had the best sounding transmit audio quality on AM.  I was not looking for which radio was absolute loudest (that may be yet another test), but which one had the most (admittedly subjective) pleasing to listen to sound quality.  I tried my best to set each rig up so as not to give an unfair advantage to either one.  The Browning was equipped with an unamplified D-104, while the Tram was hooked up to an amplified Silver Eagle D-104. The amplified microphone was set so that the sensitivity level was about equal to the level of the unamplified mic on the Browning. The Tram's Transmitter Tone Control (TTC) was set to offer up a similar frequency response to that of the Browning.  I also tried to eliminate any preconceived favoritism by disguising which rig was which, instead simply referring to them as "A" and "B".  I defeated the Browning's ping (an obvious give-away) by turning up the squelch and I proceeded with the test.

 

I had a total of eleven respondents to the test.  Ten of those were listening to the radios directly over the air, and one heard the radios through my streaming audio server.  The results of the test indicated that seven of the respondents thought that the Tram sounded better.  Two people believed the Browning sounded better.  One person heard no appreciable difference between the 2 radios.  Finally, 1 person preferred the sound of the Browning for "laid-back local" talking, but thought that the Tram would be better for pile-up busting when talking DX.  I realize that different mic's on either radio may have changed the results. Also with the Tram's TTC, it's really easy to alter the sound characteristics.

 

Winner: Tram

 

 

AM Receiver performance:

During several consecutive Classic Radio Roundups, I pitted the Tram against the Browning to see which rig heard stations better, and had the most pleasant overall receiver quality. During one roundup, the skip noise was very high which made copying the locals tough.  Neither radio could pull desired signals out of the mess better than the other, but the Tram's Tone control made the high pitched sound of all those signals heterodyning a little less annoying, and the adjustable noise limiter helped to shave the edge off the noise.  Turning on the Browning's noise limiter also took the edge off of the noise, but at the expense of some slight distortion of the signal.  Audio fidelity from both radios was better than most solid state radios, with a tonal richness which can only be gotten from tubes.  The Tram was the easier of the two rigs to operate since the transmitter and receiver could be switched with a single crystal selector (or a the manual tuner).  However, the Browning's manual receiver tuner was not tough to tune in and didn't drift once tuned in.  The Tram had a few more knobs to tweak, like an adjustable noise limiter, which could set a fair compromise between reducing hash noise and distorting the desired signals, and a switchable noise blanker for those pesky neighborhood weed-wackers and leaf blowers.  Both radios' "S" meters were fairly linear and tracked signals well. And both radios meter zero had to be readjusted from time to time. The Tram has 5 db better adjacent channel rejection, but that fact did not make a noticeable difference in local operation.

 

Winner: Toss up

 

 

SSB performance:

This one was no contest. The Browning's receiver, without the help of a narrow 3 Khz crystal filter did not seem to hear the weaker stations as well as the Tram (wider bandwidth = higher noise floor). Also the Browning could demodulate either SSB mode simply by shifting the tuner. You really couldn't tell which sideband the other station was on.  Also the Browning's BFO would drift requiring frequent touchups of the clarifier. After talking with other Browning users, I find that this is a common occurrence, and not a problem in my radio alone.  The BFO circuit was also not as robust at demodulating the SSB signal, and I could not get anyone to sound "AM-like". Although no one was difficult to understand. The Tram was a much more "typical" SSB performer, although when using the manual tuner, there was some drift evident. I don't know if this is a design issue or a product of the age and "mileage" of my particular radio. Also, the Tram's SSB transmitter put out nearly twice the power of the Browning, at 17 watts vs. about 10 for the Browning.  I thought perhaps the Browning might have a slightly weak final tube.  But after talking to other Browning users, I was told that 10-11 watts is fairly typical for their power output.  Both radios seemed to transmit good quality audio on SSB though.  It was an even split over who liked which radio's audio quality on SSB.

 

Winner: Tram

 

 

"WOW" Factor:

Ok, this one is purely non-technical and very subjective, but you know when someone drives into a public place with a really cool car, how everyone flocks around to get a good look?  Well similarly, when I run the Browning, someone almost always has to pop out of the woodwork to comment about that "sweet sounding Browning".  Not that the Tram sounds bad (it actually won the AM audio contest), but that tell-tale ping of the Browning lets everyone know that the King is now on the channel.  There's also something truly enjoyable about running the Browning, a feeling that exceeded the feeling when running the Tram, even though the Tram was every bit as nice. There's just "something" about a Browning.

 

Winner: Browning

 

 

Conclusion?

 

Well, there you have it.  If I were to count up the points, the Tram will just edge out the Browning.  But determining a real winner takes more effort than just totaling up a few specific categories.  Much of what will determine which is the better radio depends on how the end user will operate it.  For the operator who spends a great deal of time on SSB as well as AM, the Tram would make the better choice.  But for the strict AM operator, the "wow" factor of the ping, along with its fantastic receiver sensitivity, would tend to favor the Browning.  I realize that I'm probably copping out somewhat by not picking a definitive winner, but I've come to realize that this is a contest where subjective opinions count for much of either radio's appeal, and my single opinion alone is no more valid than any one else's.  Also, I'm basing this comparison on 35+ year old radios, where many of the parts have aged.  Many have also been replaced, but it's probably a safe bet to assume that neither of these radios is performing exactly the same as when they first left the factory.

All I can say is that I'm glad to finally own both of these legendary giants.

 

 

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