Chronicle of Parking Lot Radio

This image of AM-Modulation-Measurements- belongs there somewhere...

Still hope to find the images of the completed unhoused unit they had posted, it was so cool

Oh! It belongs to the May 21 update, I put the wrong one, it should have been this one

Just found the September 2020 update which shows one of the images I was looking for...

Development Update, September 10:

Testing and programming has begun on the transmitter circuit board!  First, we will do a check of the main circuitry to make sure everything is in order.  Then, the software has to be installed using the programming connector at the left hand side of the board.  Once everything is up and running, then RF testing begins.  A key aspect of this testing is validating the integrated automatic antenna tuner, which is at the bottom of the circuit board.  Once we have everything dialed in, the prototype will head to the testing lab for FCC certification.  Once approved, the unit will be available for sale.  Stay tuned, we’ll keep you posted!

It's all very fragmented up there on different pages and dates, kind of frustrating, 

https://web.archive.org/web/20200513195919/https://parkinglotradio.com/development-updates/

Ahhh.. I should of waited, there was also an update in October..

In summary, there are 5 things in particular that caught my attention. The first of which were during the April updates..

•• Initially, from 100mw input he said he was "getting about 60 milliwatts output.  This is a great start, and we think we can improve the efficiency to a better level with some circuit refinements", but he never mentions that again. So I wonder if that had been improved, and it also brings  up the question of what kind of efficiency do the Rangemasters and Procasters have??

•• It said it's harmonic distortion "is running just under 1%, which is a very good". So again, it brings up the question of how do our Rangemasters and Procasters rate?

••• The May updates it says he abandoned the original audio processor circuitry they were using and "designed a circuit with a professional part that produces sound quality that rivals the sound produced by processors that radio stations pay thousands of dollars for.". Well, what "professional part"?, he implies it was based on what a "professional wireless intercom" uses, and described it was "definitely the right answer.".

•• In June updates he says designs an "automatic antenna tuner".. Does that mean like the Talking House? Was that a good idea?

••• But he said in July is what I wonder about most of all..  the "control box circuitry" that  interfaces "to the cable that connects to the remote transmitter"...  What's being said there? - Is it that the processing was a separate unit used inside that fed to the transmitter outside? Or was he talking about an outdoor ATU like the Talking House offers?

•• Lastly, when Radio World reported on October 3, 2022:
“Parking Lot Radio” Is a No-Go
Radio Design Group won’t proceed with the initiative
https://www.radioworld.com/news-and-business/parking-lot-radio-is-a-no-go

"...Hendershot now tells Radio World that the costs would have required a retail price too high relative to the market.
“It was not a decision we made lightly, because we really believe the product would set a new standard. But at a price over twice what the next lower competitor is at, we just couldn’t see it working. Add to that the supply chain issues — and there are many — and it just became infeasible.”

It's not clear to me what he meant by "the next lower competitor"   - If that meant the "second most expensive" transmitter then it referred to the Procaster, which at the time was $695 (and up),  https://www.chezradio.co m"> https://web.archive.org/web/20200922215119/https://www.chezradio.com / (incidentally I think Procasters webpage was more attractive than it now), thus meaning the new PLR Transmitter would, if they had followed through, would have cost $1,400, at least six times the price of what they originally projected it would have been..

"Units will be sold direct at first. Hendershot projects a price of under $250, though that is not set yet."

I also wonder why, after he abandoned the certified pre-built unit plans that he didn't follow through by offering a kit version of it instead 

@richpowers Seems from this it's been scrapped? Too bad if that's the case.

@mark Well yeah.. It was scrapped 5 years ago. Don't you remember hearing about the new "Parking Lot Radio" that was in the works back then by Jim Hendershot's company Radio Design Group? I thought it had been a hot topic here for a while too.. Maybe it had just been to me, I watched it closely for months, but then after it was finally finished they essentially said Nevermind, it ain't gonna happen after all.

Now, I was just kind of documenting what had happened. Thought it was an interesting look at it after the fact is all

I guess that was too much information to lay out at one time because it kind of diluted the most interesting points of the thread.

- which really was the design and components of the transmitter itself and the questions that arises from it.

Long drawn out post like mine above often times tend to not even be read, I should have taken that into consideration before posting, but my primary objective was to lay the entire story out for prosperity, as it were. Personally I thought it interesting stuff.

Just too much at once I guess.

Great summary of the history of this never completed transmitter.

As their name suggests, and if what they write is accurate, they appear to have an in depth design knowledge of this topic.  Unfortunately, it's a whole other ball of wax to take a working prototype to market, as I'm sure the heads of Chez Radio and Hamilton would attest to.

First and foremost, you have to have the requisite financial backing, which they did not appear to have.

It can cost a lot of certify your transmitter, particularly if problems are found during the process.

Then, unless you intend on building each sold unit by hand, you have to get your boards manufactured, probably offshore and in quantity to make the per unit costs reasonable.  That can cost a bundle.

You have to assemble each of the final units, with enclosure and documentation, into a retail package.

And finally, you have to market that finished product, along with advertising, a professional website, etc.  During that potentially lengthy process, you have to be able to financially weather a lack of sales until things get rolling.  That can take months, if it does ever happen.

Designing and building a prototype is probably the easiest and least expensive part of the entire process.  Sometimes the quickest as well.

Proper business and cost analysis at the beginning of the cycle might have saved them a lot of time and effort.

@artisan-radio They've been around about 40 years so I would think they know what their doing, but they don't really have much in the way of products other than some wireless intercom systems and some kind of 18" antenna that cost $1,300. So maybe that's why they didn't realize what they were getting into when they d coded to design and market a certified part 25 transmitter. They appear to deal more with services and such. They do publish a lot of rather interesting articles, mostly radio related and vintage audio stuff.. I really don't know much about them but do like their articles. https://www.radiodesigngroup.com/

I wonder if he ever considered marketing the transmitter as a kit after realizing the snags involved with a new certified device.

Knowing first hand all involved in the making of a transmitter from conception(not the medical term) to the final product. I was with Gerry from the beginning to the end of the newer Procaster FM. Not all the time but you know what I mean.

The biggest expense is is not the manufacturing but the certification. The lab here in Oakville near Toronto charges $1000.00 per hour.
Once the prototype is finalized, the manufacturer after trial and error, trying different chips, different component configurations to get performance to the standards desired, designing a cabinet, getting the final prototype, having to know the rules in manufacture as more trips to the lab, having to redo or change something can add up many $1000s of dollars. All components/chips used all cost money in the development process as the manufacturer has to buy all the stuff to do the build.
The manufacturing not so much money. He sends via email the information of the prototype to his contact in China and they can have 100 boards made to his specs and sent back in a week via DHL express. 
He has the cases made separately and the labels separately. 
When/if he gets orders he mounts the transmitter boards in the cabinet, connects the antenna and checks it over and sends it out. Same with the procaster AM but the antenna for that is a separate piece.

As for the costs of having it manufactured, when I took the Sean Cuthbert 6 band processor over for Gerry to see how it was all hand done the first thing he said was why doesn't he just have boards made with all the components marked designed for his cases and he can get 100 boards made for $30 dollars in China. Doing it all hand built like this a painstaking job, crazy.
To have the boards made with all components, finished product and getting 100 made is not that much money at all.  But getting 1000s of discrete components, IC's, transistors, other components, for each one and doing it like this is costing so much time and way more money. No, the certification is the most money. The second cost is time. It took Gerry about a year+ from the idea to the final product.
Now in the case of the Sean Cuthbert AM transmitters he doesn't certify it so no big amount of costs to recoup and fortunately in the USA certification isn't mandatory like it is in Canada as I understand. Sean Cuthbert couldn't do the same thing here. All FCC cares about is it operates as per rules but if there was a visit and an issue the user would just say it's a kit and the manufacturer states that when put together as per instructions with parts supplied it operates at part 15 rules. The manufacturer I would assume then would be responsible. That is if the end builder/user didn't do any mods.
You just need to have the money for parts, test equipment like FIM, scope, spectrum analyzer, etc and for the certification. And of course be an electronics engineer or have sufficient expertise in circuit designing.

@mark I want to come back to this later as there's a lot you laid out there and I need to let it absorb. But want to address one particular thing that really jumped out at me.

..fortunately in the USA certification isn't mandatory like it is in Canada as I understand. Sean Cuthbert couldn't do the same thing here. All FCC cares about is it operates as per rules but if there was a visit and an issue the user would just say it's a kit and the manufacturer states that when put together as per instructions with parts supplied it operates at part 15 rules. The manufacturer I would assume then would be responsible. That is if the end builder/user didn't do any mods.

Not quite. Certification is mandatory in the USA to manufactured/market a transmitter (assembled). But there is no requirements that the transmitter you broadcast on be certified. Certification is exclusively a marketing requirement.

The sole requirement for an individual, organization or business to legally broadcast is Compliance with Part 15. The person who is broadcasting bears the full responsibility of ensuring it confirms to part 15 rules.

The manufacturer (or a provider of a kit) bears absolutely no responsibility whatsoever if your broadcast is not compliant.