13 years later…

Most of us are old enough to remember the events that happened on a sunny September morning, 13 years ago. What many may not have realized , was in the north tower, there were six television transmitter engineers for five of the eight TV stations located on the 104th and 110th floors. These six engineers where just doing their normal job until that morning when the cowards attacked their building. Take a moment out of your day to remember them, in remembrance of the other almost 3000 who died that very day.

If you haven’t had a chance to visit my tribute site to the engineers, and the World Trade Center broadcast facility, please do so when you have a chance.

Robert Pattison , transmitter engineer for WCBS-TV.
Robert Pattison , transmitter engineer for WCBS-TV.
Isaias Rivera, Transmitter engineer for WCBS-TV
Isaias Rivera, transmitter engineer for WCBS-TV
William Steckman, Transmitter engineer for WNBC-TV
William Steckman, transmitter engineer for WNBC-TV
Steven Jacobson, transmitter engineer for WPIX-TV
Steven Jacobson, transmitter engineer for WPIX-TV
Don DiFranco, transmitter engineer for WABC-TV
Don DiFranco, transmitter engineer for WABC-TV
Gerard "Rod" Coppola, transmitter engineer for WNET-TV
Gerard “Rod” Coppola, transmitter engineer for WNET-TV

Changing the fluid… on your transmitter… P1

On most high power UHF, some VHF and some FM transmitters, the transmitter’s “residual transmission heat” is dissipated by liquid cooling systems.

Transmitter Liquid Cooling Plumbing for a Comark high power UHF transmitter.
Transmitter Liquid Cooling Plumbing for a Comark high power UHF transmitter.

Here in the US, it is very common to use a mixture of distilled water and Propylene Glycol (“Glycol”). The mixture varies based on the environment of the transmitter and the location of the external cooling systems (heat exchangers).

Transmitter heat exchangers mounted outside.
Transmitter heat exchangers mounted outside.

Glycol is used because it will prevent the outdoor systems from freezing. It also prevents the water from boiling when transferring heat. Glycol is a nasty substance if you have to handle it, with an invasive pink dye, which is very difficult to wash out when dried, and a perfume agent that is pungent at best. However Propylene Glycol is considered non toxic. (Unlike Ethylene Glycol, which is used in radiator fluid and plastics manufacturing.).  Glycol is a chemical that can leave behind residue, which over time, especially when mixing with water, can cause the pH balance and other properties of the glycol to change. This breakdown of the elements of the glycol, causing deposit buildups in both transmission components and the cooling system itself. It is important when using a piece of transmission gear, that this chemical be tested every other year, to determine if it needs to be changed out before that damage occurs.

We take the sample using the drain port on the IOT tube bottom.
This is done by running the fluid into a small bucket for about 15 seconds to flush out the crusted contaminants. Then using the sample container, we fill it slowly with the fluid.

Glycol sample collected underneath the IOT
Glycol sample collected underneath the IOT

The company we use, Dow Chemicals, provides the sample containers to put the samples in. They give you documentation and a little box to ship the samples out.  Because we have two discreet cooling systems, two samples of the chemical are sent.

Dowtherm SR-1 contained and ready to be sent for analysis
Dowtherm SR-1 contained from both systems and ready to be sent for analysis.

In a few weeks, we will get the results, and based on the results, will determine if we need to flush the entire cooling system and replace the Glycol in it.

Da Crane, Da Crane!

WGBH-FM (89.7 Boston) on Blue Hill in Milton is undergoing an antenna replacement. As part of the replacement, the top mast  is also being replaced with a new mast. This morning I caught this on the way into work, the crane is up working on the replacement.

(Sorry for the fuzzy picture. Smart phone picture!)

WGBH-FM crane setup to replace antenna and pole.
WGBH-FM crane setup to replace antenna and pole.

What lurks behind the walls…

We had an ongoing issue in the “satellite office” (bathroom) where the light would cycle, like we took a quick power hit. I always just attributed it to the ballast or the bulbs being funky, but today I decided to inspect the wall-switch, just to check. Sure enough, this is what I found. Those who know electrical theory know why this is extremely dangerous. The “electrician” who may have installed this switch, never pre-twisted the wires before the wirenut, and never twisted the wirenut tight. So the neutrals both became loose and over time arced to the point of creating oxidation on the wires.

Needless to say, the switch has been replaced and the wiring is all cleaned up now.  You never know what lurks behind the walls sometimes…

Well cooked neutrals.


After waiting for the floor buffers to finish drying, I was hanging outside , watching these ominous clouds go by outside.

Storm Clouds at the transmitter in Needham.
Storm Clouds at the transmitter in Needham.


It’s the return of the NECRAT-QUIZ

Update. This WILL be the LAST NECRAT Quiz, seeing how little response I’ve received.

I have decided to bring back a classic!! It’s the NECRAT QUIZ!!
While there aren’t any prizes yet, there could be down the road…

So with that……

Can you identify this transmitter site?

QUIZ Aug 2014

You can guess by registering here, or by using the Facebook page. Hints will be given before the end of the month!  Good luck!!


Welcome to the NEW NECRAT

Welcome to the new style of NECRAT. I call it NECRAT version 5.0!

This brings NECRAT into the 21st century with a fresh look, more detailed updates, and an exciting way to keep this site on the top of your frequently visited list! The new format will allow me to go into greater detail the changes I made here, and the updates. It will also allow me to start some new features that will make you want to come back to the site often. While there was a lot on the original site, this will just add to it. Don’t worry, the very hefty indexes of pictures and descriptions remains free to view (in fact the whole site is free, still!!). Just go to The NECRAT Wiki to see all the content you known and love here on NECRAT. I hope you enjoy these changes i’ve made, as I have put a lot of hard work and effort into this upgrade for you my fans!!

Mike Fitzpatrick
NECRAT founder and owner.

P.S.! feel free to sign up for an account to add your comments to the site. If you sign up but don’t receive the email activation , just email me and I will square it away! – Mike

A Broadcast Engineering Website