Dave Harmon

Hi Sid.......
I think Ted was in Albuquerque and at the time...early 70's....I was in Torrance, Calif.
I never met Ted.....

Bax

My Feedback: (11)

That's not a Tower receiver in the picture. The receivers that came with that transmitter were of molded nylon in an off-white color. Servos, too. They used the Kraft-Multicon connectors.

KraftyOne

Thanks Bill,

We didn't think it was Kraft made, for the reasons you confirm.

An advert in an RCM from December 1980 has provide the answer. The question now is, who made the receiver for CHC??

Soar RC

Looked like this. My whole NIB single stick Competition 6 with RX and servos.

jpooch00

After saving up for over a year, I bought a Pro Line 6-channel, 2-stick back in the day.

Without a doubt, the biggest, most overpriced POS system I ever owned!! NEVER really worked right - not once, not ever. It was returned for repairs numerous times with zero positive results.

Finally sold it for a few pennies on the dollar to some other poor fool in the club (with full disclosure of problems, of course, which he already knew anyway).

Perfect company to go out of business and good riddance, if you ask me. A true determent to the sport all the way.

Used the money from the sale to buy a used Kraft system and it was smooth sailin' from then on.

Mark Powell

Interesting comment.
About a year ago I purchased a two stick Pro Line Competition 7 from a guy on another North American forum. Mostly out of curiosity as they were never marketed here in the UK where I live (the Japanese were already beginning to take over by the time Pro Line got started) and I suspect mine may be the only one in the UK. It is a complete set with receiver, 7 servos, wiring harnesses, servo trays, etc. and appears to have never been used. The transmitter battery was leaking but thankfully it was disconnected so corrosion did not reach the rest of it.
Your experience seems unfortunate - mine, made, I think, in 1975, worked perfectly in all respects when I replaced the batteries. It was on 72 MHz, illegal in the UK, but I flew it for a couple of short flights without problems. Then I converted it with a Multiplex (popular in Europe) 2.4 GHz module. I used a Multiplex module because I use Multiplex already and it keeps everything compatible. This was very simple to do and took less than an hour - the Pro Line encoder output/power connector even fits the JR type connector that Multiplex use on their module and it all fits in the same space that the original RF section used. Other than my first test I have not used the Pro Line servos as by modern standards they are large and heavy, but I did make one 'pulse inverter' (one transistor and a couple of resistors, plus a JR type plug and socket) to try the servos out (Pro Line servos used a negative pulse) and with that pulse inverter they work fine with the modern Multiplex 2.4 GHz receivers..

Sticks. It has the all metal open gimbal sticks, which were made by Pro Line, though the actual part stamping was done by a local contractor. Ron Chidgey designed the all metal single stick version but the simpler all metal sticks used in the two stick radios were probably not designed by him. They are superb in function, if rather crude in construction. Kraft purchased them from Pro Line and used them in the 'Signature' series.
I see the single stick radio in Soar RC's post #29 uses a Kraft plastic stick, rather than the 'Chidgey' metal one, even though it is from the 'Competition Series'. Maybe it is from one of the several times Pro Line were in financial difficulties.
It would appear that there was a 'two way traffic' - Kraft buying the Pro Line sticks for their top 'Signature' radio and Pro Line buying the 'regular' Kraft plastic stick for their lower cost 'Sport Series' radios and some of the 6 channel 'Competition Series' radios. AFAIK the 7 channel Pro Line 'Competition Series' version always used Pro Line's own metal sticks, in either the 'Chidgey' single stick form or the simpler two stick form.

Jim Fosgate later produced the world's first multi channel car audio. He then went on to work for Dolby Labs and actually designed their 'Dolby Pro Logic' multi channel movie sound system so is well known in the movie and audio world. There is a Wiki entry about him, but it says nothing about his R/C days.

Pro Line quality. It seems reasonably well made, though the encoder board is terribly cramped. They even had to cut a lug off the charge/trainer socket to give room for a transistor. At least it is very simple (rather old-fashioned, even for 1975) but it doesn't use any ICs, which means it is easy to maintain in the event of a fault as it contains no components that will become obsolete, as ICs tend to do.

I have not 'investigated' the receiver as apart from my initial try out I have not used it. It's in a nicely made black metal case with a Pro Line sticker on one side and a sticker with their name, address, and FCC stuff on the other. I have thought of removing its insides and inserting a (much smaller) Multiplex 7 channel 2.4 receiver to make it look 'authentic' but as it will be buried inside a plane there seems little point.

My transmitter works fine and is in regular use.
But I see NOTHING to justify its (then) high price and over-hyped reputation.
Other than the sticks it is a simple and low cost design, which is good of course, but it is no more 'sophisticated' than any other US system of its day - they were ALL satisfactory, unlike some of the British efforts.

Truckracer

My Feedback: (19)

Responding to an old post but much of the above also reflected my experience with Pro Line. In the early 70's and in my early 20's, I didn't have a lot of money but thought I needed a Pro Line radio so spent just under $500 for a new Competition 6 with every fancy gadget they offered at the time. It never did work right and had to be returned to the factory twice for major modifications to both the RF section and the servos. It never crashed an airplane but I never felt secure flying it. I sold it at a great loss and went back to Kraft radios where I stayed until their end. My Pro Line phase was quite the expensive lesson for a broke kid.

Mark Powell

The strange thing about the problems both you and jpooch00 had is how can these things NOT work correctly?

I've not looked closely at any other system than Pro Line but the Pro Line system is EXTREMELY simple. There is almost nothing to go wrong. The transmitter encoder circuitry is a discrete component 'multivibrator' consisting of two transistors, a couple of capacitors, and a few resistors. This is a 'standard' circuit found in any basic electronics book and is used in tens of thousands of electronic boxes for all sorts of purposes.
In the Pro Line transmitters it provides the 'frame rate'.
It is followed by a string of 'half shots', one for each control which provide the pulse widths, the first one triggered by the multivibrator and the others triggered by the previous one. All done, it starts over again for the next frame.
Unless a component fails this thing is so simple it CANNOT go wrong. The components are very high quality - for example, the control pots on the sticks and ancilliary controls are all Bourne's, the best there is. The pre-sets inside are also Bourne's.

And although these things are referred to as 'digital proportionel' there is nothing 'digital' about any of it. Doug Spreng's original idea of replacing variable voltages to the servos with variable pulse widths as above is good and was used in all of them, but it isn't 'digital' by any stretch of the imagination. It's all simple, basic, analog stuff.

And the servos are basically Kraft.

As for the RF sections, both in the transmitter and receiver, they are no more complicated than a kid's walkie-talkie. (How any manufacturer could justify the several hundred dollar prices for this simple stuff I cannot imagine.)

So you have to be a real BAD electronics designer to screw it up . And all I can say about Jim Fosgate is he left R/C and went on to much higher things and AFAIK he is still successfully designing highly regarded stuff today, at the age of about 70, so he must have some degree of ability.

Truckracer

My Feedback: (19)

My problems were mainly centered around the servos. Though Kraft mechanics, the electronics and pots were all Pro Line .... actually more similar to EK than Kraft. For my radio, Pro Line had just switched away from the all metal pot wipers to the then new carbon button type and these were good for about 10 flights before some maintenance was required. They replaced these with different wipers ( I no longer remember what kind) but the maintenance cycle was still excessive at something like 50 flights. I know many other people complained about these at the time and the problem wasn't limited to Pro Line. There were two or three types of pot elements in common use then and one of them was quite abrasive to the wiper. Another problem was the extremely tight deadband in the servo electronics that exaggerated the pot issues. Any pot issue at all was made completely intolerable by the tight deadband. While the tight deadband was desirable for improved flight performance, it just wasn't tolerated very well by mechanics and electronics of the period. One learned to do servo maintenance at the field as problems developed.

My radio also had an RF problem (range) that may have been simple tuning. I don't remember or know for sure the exact nature of the problem all these years later.

While the radio had a fairly simple design, the component count was extremely high which can add to the number of potential failure points. Boards were extremely crowded and in the receiver each servo and power connector had it's individual wire lead and Deans connector. The huge wire bundles were horrible to deal with in some cases. As with all Deans connectors, one had to be careful to guard and not flex the solder connections for fear of wire fracture. This was in a period where most radio brands were reducing component counts with IC's and going to simpler crimped connectors with block connectors on the receiver.

I have nothing against Jim Fosgate as the radio was pretty much standard fare for the day. I do believe the Hype was perhaps better than the product and I regretfully bought into that. At the time I could have paid for a pretty nice pattern plane for the $$ I lost on that radio.

grotto2

My Feedback: (2)

I seem to recall reading an article about PL back in the day touting some "safety" circuitry to justify how great a radio it was.

One feature was reverse diodes across all battery cells in case any went to an open circuit. I don't think anyone ever saw a nicad cell do this and the additional parts effectively lowered the MTBF.

Another feature was something called a Pulse Omission Detector in the receiver decoder. I forget the exact details, but it was supposed to detect unusually short received pulses and suppress their path to the servos. The idea being that you could fly through interference glitches.

Does anyone have more information on this?

[email protected]

Sid Gates - you have already been given the new about Jim Martin. His Craftmanship Museum is still open and worth spending a day. It is not far from San Diego, for those of you who come there to see the fish and the monkeys. .
An update on Mike Pezak/Custom Injection Molding! Mike sold the company, maybe as much as three years ago, to one of his previous customers who has no interest in the model stuff and let it all die. Eloy Marez (Orbit, Airtronics, Model Builder Magazine, etc!)

Mark Powell

truckracer/grotto2

All interesting stuff. I confess I bought the Pro Line a year or so ago purely for 'nostalgic' reasons (I'm about the same age as Fosgate) and because of the hype surrounding them (unlike Bonner, Kraft, F&M, and Orbit they were unknown in the UK at the time and today my fellow UK flyers seem to think it was some small and inferior USA manufacturer but I know different ).

AFAIK Fosgate never had any great financial interest in Pro Line, he was just an 'employee', hired away from EK to do the electronic design for the expert and well-known flyers who had little radio knowledge but hoped to sell a radio on the strength of their flying expertise. But he must have been good (I never intended to imply that he wasn't) as he went on to great success and a certin 'renown' in other fields.

It worked for a time, (Having 'Champions' endorse the product is always good marketing and those particular champions not only endorsed Pro Line. they owned it. But Pro Line was too late in the market for big sales - the Japanese were already appearing when Pro Line was just starting. And because the Japanese merely copied existing US circuitry they didn't have to do any 'research' or much in the way of testing so had a price advantage.

I see from truckracers post that most of his problems were 'mechanical' rather than electronic. And those carbon wiper buttons never worked well in anything, despite experiments with different sorts of carbon 'derivatives'. I think most modern pots use beryllium wipers and beryllium would have been difficult to obtain in those days. Multiplex certainly use it, and the wiper is separated into two separate 'fingers' which halves the wiper pressure. Their servos last 'forever', but unfortunately they are no longer made - the latest ones are re-labelled Hitec servos but with red cases.

Component count. Yes, the Pro Line stuff does have a high component count, which is an inevitable result of not using ICs. But it gives the modern restorer an easy time. Many of the ICs were custom designed by Texas Instruments, Signetics and others specifically for the R/C market and are no longer available.
And the Pro Line transmitter encoder board is horribly cramped, which is completely unnecessary as there is plenty of space in the transmitter. They are all cramped on the receiver and servo side as all makes were trying to outdo each other on low weight and small size. This was done by most manufacturers in the servos by using a now long discontinued Signetics IC amplifier, rendering those servos unrepairable today.

grotto2

The pulse omission detector you mention was an attempt at reviving some sort of function to replace the 'failsafe' used in several early makes, notably Bonner (Digimite) and the first Krafts. The complication of this failsafe resulted in the prices being too high and that compilcation decreased the reliability anyway so it was quickly dropped. Multiplex used a 'computerised' version of a POD which they called an 'Intelligent Pulse Detector' in their last pre 2.4 GHz receivers. It worked extremely well (the servos slowing slightly rather than glitching) but would have been near-impossible to do with 1970's technology.

Truckracer

My Feedback: (19)

I'm not sure about Pro Line's approach to receiver / decoder design as I have never seen their schematics. I was part of a discussion with Phil Kraft at Toledo in the early 70's regarding receiver design. Part of the problem with many decoders was that when a receiver was being flown constantly through varying signal strength areas and sometimes momentary lacks of signal (a normal condition with any RC receiver) some decoders would go crazy for a bit and output all sorts of random pulses to the servos causing the very common glitch we were all familiar with. Kraft and others knew it was important for a receiver to "drop out and recover" quickly and without glitching during these poor signal periods. Some designers understood this concept but others never quite got it. Some designed more sensitive receivers than necessary but this caused other problems I won't go into here. The fix was fairly simple and involved having the decoder just shut down when there was a lack of a clear sync frame and / or when there was a low ACG voltage. Shut down meaning there was no pulse outputs to the servos during this time. Most servos would just do nothing when there was no pulse input so this was a sort of poor mans "hold" during bad signal periods. The concept being that most flyers would hardly notice the lack of control for a fraction of a second where they would certainly notice a glitch that showed up as an incorrect control input. This all seems so simple today but through the 70's more than a few receiver designs from some companies continued to have free running decoders that would output all sorts of trash to the servos during bad signal conditions. IC decoders were just as vulnerable as discrete component designs depending on how they were designed and incorporated.

I don't remember what IC the Pro Line servos were using but I don't believe they were the common Signetics or the Kraft TI design. I don't know if the Signetics IC was even available yet. One positive note about Pro Line servos (and EK in many cases), they used a much higher quality servo motor (read that more expensive) than what Kraft and many others were using. I won't go on about servo motor quality and reliability here though.

HighPlains

My Feedback: (1)

As I recall, F&M and Bonner used fail safe. The thinking of Kraft was make it simple, less parts gave higher reliability, lower weight and lower cost. The early systems also used 7 cell battery packs, but Don Mathes did four cell systems with the center tap and his fingerprints are all over Kraft and Orbit. EK pushed the two wire battery/3wire servo which was a fantastic advance with the bridged amplifier. Proline did the diode batteries, but NiCads almost never failed with an open circuit so it seemed more as a marketing ploy.

I always assumed the Kraft "Z" stick with the folded metal vale was made by Kraft, I've got a few with that stick, plus a Proline Custom Competition with the cast aluminum and machined sticks. What I liked best from transmitters of that era was the availability of cross trims on high end rigs.

jaymen

Great post.
Final chapter for Pro Line was the Ace R/C years. The Silver Seven receiver was used, with a deans style connector block, and the servos were typically D&R mechanics, with Geizendaner style pot wipers, which worked pretty well. I believe these were about the most reliable and simplified versions of the Pro Line, plus Ace offered some options like dual rates and servo reversing.

I have a few of the really small black metal cased Pro Line receivers, and they have four IF tuning cans, whereas most radios only had three. I have tested them and they have fantastic sensitivity and adjacent channel rejection for an AM wideband receiver. In my opinion, it was a really good receiver for it's day.

What I never liked about the original Pro Line systems was that their servos used a negative going pulse, so you had to buy pulse inverters and put them inline with the servo to use them with other brands, or to use say a Kraft servo, you also needed the pulse inverter. Before Ace took over, they sold a ton of the pulse inverters.

g-rock

My Feedback: (1)

I bought a 6 channel Pro Line back in 1971 mainly because of it's RF rejection. Had Logic Troll at that time but wanted something better (at least that's what I thought). My models at that time were almost all metal and some still are to this day. Kraft just wouldn't do.

My Pro Line still works. I made a hex buffer using a C4049 chip to convert the output to positive pulse. It now can use any positive pulse servo such as Futaba.

Gene

OhD

I came across this thread accidentally and while I didn't read everything, I did see many, shall we say bad recollections. Number one is that, Jim Fosgate did have a financial interest in Proline along with a number of top pattern pilots of the day. They started in Alabama in or near Huntsville but soon moved to Phoenix due to Jim's wife's health concerns. His design of the electronics was unique and had no resemblance to Kraft except for the fact he used Kraft/Hayes servo mechanics. The open gimbal stick assemblies were designed by Ed Keck and were the best gimbals made at that time and what made the system so popular with top pilots. Eventually Kraft actually used Proline gimbals in his top of the line Signature Series. Proline was sold to Pace who actually made a better gimbal but they eventually ran the company into the ground and Joe Bridi and Lou Stanley bought the pieces but never produced and systems to my knowledge.
I thought I would help by pointing everyone towards the Radio Control Hall of Fame. When I checked it out (googled it) I found photos but no history. We should probably get all the folks who have info, to contribute to some kind of document so this history is not lost forever.

Jim Oddino

Dave Harmon

Hi Jim......
Just to add to the history of PL I thought I should mention that in about 83' I bumped into Lou Stanley at the BIRD field which was then located at the Dominguez Hill site in Long Beach/Carson.
We got to talking and he mentioned he had the residue of PL and was going to dumpster everything if he could not find someone who would take it all.
He had all of it in his car so he just gave it all to me.
It consisted of a Tektronix scope, a test set to plug into the tx to select each channel for display on the scope during alignment, a box of finished receiver/decoders, several 6m and 72mhz tx modules, a complete Competition 6 tx with the Keck gimbals equipped with the Spectrol pots, a cabinet of various resistor and small pots totaling about 200 pieces and a set of full documentation including mechanical assembly cartoons .
I really don't think they realized what they were getting into because as you know there is quite a bit of commitment to mfgr a R/C radio.....and they certainly could not do it with the tidbits Lou gave me all those years ago. More than likely there was more components that he had already disposed of.
I still have all of it.

Best.....
Dave...

OhD

Hi Dave, Sounds right. I had dropped out of RC in1981 and was getting interested again in 1983/84. I went to Bridi's shop and remember they had loads of stuff including finished subassemblies. I got one of the transmitter cases with the newer gimbals (single scissors) with New England Instrument Pots and built new electronics using the Signetics IC encoder. I still have it. I was also talking to Kraft in those days encouraging them to consider PCM. This was after Phil had sold and was no longer part of the operation. Then one day I went down there and they had acquired a Futaba PCM system and I concluded they were too late. That was the end of PPM transmission as far as I was concerned.
By the way ,why did you leave sunny Southern Cal?

Regards, Jim

Dave Harmon

Hi Jim.....PM sent.

Dave