Frequency hoarder

Frequency hoarder (n). One who desires to add so many frequencies to the internal memory of their scanner or other radio device that they can easily fill the 1000 channels on a GRE scanner or any of the recent Yaesu radios* and find themselves dejectedly trying to figure out what won’t make the cut.


I am guilty of being a frequency hoarder. When will the scanners just read a CSV file off a microsd? I’m waiting…

* except for the 817/857/897 which only have 200!! Why, yaesu? Why did you make three rigs that beautifully span DC to 512 megacycles with no gaps in am/FM/ssb/cw/wide FM and then only give us 200 pigeon holes for our frequencies?!

The MotoTRBO chirp

Motorola XPR6550

In case you’re curious, that four tone chirp your MotoTRBO radio emits as a talk permit tone is G6, C6, G6, E6; that’s 1569, 1046, 1569, 1317 hz. Each tone sounds for 40mSec with no silence between.

I’d heard that you can customize it on Hytera DMR radios, so if you want them to all sound alike, there you go.

High and dry – the Dielectric/SPX Dehydrator

This little monster showed up at my doorstep and I decided to see if I could get it running again. It’s an air dehydrator, which compresses air, separates the moisture out and ejects that, then uses it to pressurize an RF transmission line to avoid moisture intrusion.



The instructions mentioned a humidity sensor inside that has to be replaced every couple years of operation. I removed it and took a look, it showed no signs of wear or contamination. Upon powering the unit up I got a humidity alarm and the unit would just vent air via a “humidity bypass” burp valve inside which prevents it from firing wet air up the feedline should something go wrong internally.



After it ran on my bench for a while, the humidity alarm cleared and it pressurized its tank and was ready for business. The humidity sensor goes in that brass block with the 115V warning on it; the two cylinder blocks behind it contain the moisture absorbing material. The timer to its right controls some pneumatic valves which drop the pressure in the dessicant cylinders to zero every 30 seconds while the pump is running, firing air (and WATER!) out a waste hose in the back.image


On the right is the Gast pump that compresses air up to 40 PSI to run the works. On the left is all the control logic. The other unit I’ve worked with before is an Andrew DryLine, which just has one simple programmable logic controller board in it. This one, well, looking at it makes me think that the people who designed it chose to build their job security into the control logic – what even IS all of that?! 😉 The four pole contactor at the bottom doesn’t appear to actually be what controls the pump turning on and off. I… don’t even know. It works, that’s the important part. The humidity bypass valve is under that threaded hex nut/nipple on the left, and the time delay relay brick below it appears to be responsible for firing off the Excess Run alarm should a pump run cycle last too long (usually, this would signify an air leak!)image



The pump is cycled on and off by a simple Square D Pumptrol air pressure switch… off at 40 PSI, on at 20 PSI.image

An amusing note I found on the Gast pump. I’ve seen similar pumps used for a lot of laboratory applications including as low vacuum pumps, for things such as providing suction in dental offices (that slobber extraction hose they hang in your mouth)… Well, once the pump’s been used like THAT, they don’t want it back! Can you really blame Gast? 😉

imageThe Gast pumps are field rebuildable with a seal/gasket kit to keep the unit in service. On this unit, loosening four screws flanking the gray upper front cover is all you need to do to be able to reach in there and pop open the air inlet filter on the pump for cleaning, check the tank pressure, and get to most of the control logic. This is a sharp contrast to the Andrew unit I’ve worked on where you have to remove the whole thing from the rack and pop eight screws from the top cover to get to the filter, which the datasheet claims is behind the front access panel (NOPE!!!).


So long, and thanks for all the mold.

American Tower bought out Dickland.. I mean Richland… And they started cleaning house.



The mold on the walls is being removed… And the HVAC works now



The gaping holes in the entry panel have been plugged



A door mat!



I’m a happy engineer.



Boo yeah.

They still have some work ahead of them though. The tower’s elevator is hosed.



Unlike Richland, they are actually trying to get it fixed… Dickland had told me before that they wouldn’t even touch it till October. Foul demons. Ding dong the witch is….. Downsized out of a job.

Those weird fittings on the Andrew pressurization gear

High power broadcast feedlines are usually pressurized with dry air or nitrogen gas to lock out moisture (which would lead to a Very Expensive Problem). The Andrew/Commscope pressurization gear for doing this has weird tubing fittings on it for the air hoses that hook up to the feedlines. I tried doing a job on one of these systems using little brass tubing fittings from Home Depot and it just didn’t all work right, it was a pain in the /dev/ARSE to get everything to stop leaking. Come to find out, well… The fittings are actually a different system – Parker Poly-Tite.They’re apparently most common in dental office equipment and car washes.

Thank you, Dan Houg, for solving this mystery.

…And any other unspecified duties that may be added as necessary.

From Wm Watt Hairston on the fantastic “I Take Pictures of Transmitter Sites” group:

“Radio Engineer NEEDED ASAP, Duties shall include: Plumbing and toilet repair; Vehicle maintenance and repair; General building and grounds upkeep, modifications and repair; Removal of derelicts and other undesirables from building; Jewelry repair; emergency shoe and garment repair; kitchen appliance repair; office moves and logistics as requested; repair employees electronic equipment; equip, setup and tear down for remote broadcast as requested; install, maintain all phones, computers, as well as associated routers and networks; provide instant desktop support for all running OS and installed applications; Maintenance and upkeep of all FCC related compliance and record keeping matters; repair and maintain towers, transmitters and other broadcast equipment. Must supply own transportation and communications; On-call 24/7 is a must as well as a good attitude and willingness to take direction from anyone who ask….”

Telecom secrets revealed – A Sprint PCS cell site!!

What you can't see in this photo is that it's over 100 degrees in the room, lolz
The Now -- Failing --Network

This is what a particular Sprint PCS cell site in southwestern Miami-Dade County, Florida, looks like inside.

Shield your eyes, it’s horrible. No, actually, you will want to shield your eyes because the batteries were installed so badly that I felt the need to place some cut-up pieces of a plastic container in between the battery terminals and some aluminum-cased monitoring widgets that were sitting on top of them to avoid an electrical fire. (Upon testing the batteries I found then to be at about 10.1 volts DC. FAIL.)

And this kind of thing is why I trust ham radio for communications more than anything I pay a mystery team for “service” on. 🙂