If the weather were friendlier I might have driven to pick it up, but .....
It'll be fun to finally have a 5-Watter to re-build and get on the grid, probably with 2.5 or 3-Watts, based on previous tests.
The 20-Watter will also be re-built, since it blinked out a few months ago, and be the official stand-by transmitter.
I want to build remote on/off panels for them, otherwise I need to trek into the basement for sign on and again at sign off. Many nights I'd just leave it on with a blank carrier, which isn't a good idea.
Spent many trips in and out to avoid freezing too much, so the driveway down to the street would be clear for Fedex. But the Fedex lady found a side way to climb through snow banks from another street, and the LPB AM-5 arrived.
Things are exactly as MrNaturalAZ said they would be, it is the exact unit shown in the pictures on E-bay, even though the description said "LPB AM-30."
Of course there is no manual. I'll contact the seller, since he seems to have a lot of these transmitters, and see if he can help.
The unit is much more tightly packed than the LPB2-20 or AM-30, and will be a beast to analyze on the bench.
Another important question comes to mind: the original label indicates it was factory built for 610kHz, but someone crossed that out and felt-penned the new frequency: 1510kHz. The important question is whether the unit was re-fitted for the frequency change.... many circuit changes would need to have taken place.
I think I'll stick this in the corner with the other disabled LPB transmitter and pace around them every day.
Great news! My shipment only just left St. Louis this (thursday 2/7) morning. Says estimated delivery is Monday. I think I can wait. It's not like I have any choice 🙂
In any case, it is reassuring to know that you received exactly what you ordered, Carl.
What I will do is carefully un-solder and remove the two circuit cards, add many new capacitors... it looks like it has original caps from the 1980s....
And while it's open I will carefully draw the schematic, with details about the torroids.
By comparing the torroids to the ones that were in my LPB2-20, thinking that all units used the same output filters, I might be able to tell if they're wound for the low frequency or high frequency range. The other clue will be the filter capacitors, which also follow the same rules across models.... I think.
The AM-5 has a different exciter than the bigger transmitters, smaller and marked "AM-5 Exciter."
Just checked FedEx tracking - mine's getting delivered TODAY!
Oh, and it looks like the guy still has plenty of couplers and AM-5 transmitters. Some seperately and some stuck together in pairs. He even seems to have come down a bit in his asking price (and still taking "Make Offer" too) so anybody interested in getting into Carrier Current AM at a rock-bottom price (but willing to take a chance on as-is gear) should have a look. It seems most of them are on 610 KHz (but can be easily re-crystalled to any frequency from 530-830 with no other changes). With Carrier Current, the lower third of the band is the place to be for best range; just the opposite of free-radiation, where the top of the band is preferred.
I looked very hard for a frequency in the low band for the reason given by NaturalAZ... the low end is known to be best for CC.
But on 530 we have a TIS station, 550 and 590 are locals....
I actually got a crystal for 570 because all I hear there is a Cuban time station, but with only one guard band at either side it was uncomfortable being crammed... some cheap radios tended to smear all those frequencies together.
Next local station is 630, but again with 610 there would be only 1 guard band on either side.... no good.
650 WSM Nashville comes banging in here, and although 660 would otherwise be good, it actually picks up splash from WSM.
I had a crystal for 670, but a local at 690 seemed too close.
And so on up until 970, which is the lowest open frequency I have been able to chisel from the MW dial for carrier current work.
Do couplers ever go bad? It looks like all the parts would be easy to replace, so why did I just buy my third coupler?
I scrolled around on eBay and there it was. It looked like I wanted it. That's the way the picture looked.
A fresh clean LPB-TCU-30.
I made a low offer. The seller counter-offered but kept it very modest, so I typed a credit card number and soon I'll have more couplers than anyone in town.
This will be the end of the line for coupler collecting.
This new unit I just ordered from eBay is listed as a LPB TCU-30, which means "Transmitter Coupling Unit" for use with electric lines.
But while paging through my LPB literature this morning, I see another type coupler called the ATU-30, which is intended to drive a T.I.S. antenna. The ATU-30 circuit board looks just like the TCU-board, but the enclosure, judging from pictures, is a lower profile darker gray outdoor box.
The eBay picture of the unit I just ordered appears to have the outdoor enclosure, so the question arises, which unit will I actually receive?
If I bought an ATU-30, is it the same electronically as the TCU-30? Or, if not, should I modify it? Or should I start a T.I.S. station?
The TCU-30 LPB Coupler I ordered from eBay is here, and it is in very good condition, mounted in a lovely, heavy-duty, outdoor encloser.
The circuit card is labeled "TCU-30," whereas the box is labeled "ATU-30."
My question is almost answered... I think the two units are the same circuit-card, with different boxes, and the ATU has a brass mounting screw for connecting a T.I.S. antenna.
The antenna connection is a white wire inside the box connected to one of the "Line Outputs," the same ones that otherwise would connect to an electric line.
Since also I have a TCU-30, I will place them side-by-side for a part-by-part comparison, to see if there are any differences in the circuitry. One question is whether the fuses are the same value.
I do a lot of reading on part 15 forums, and this is the first time I've seen the ATU and TCU compared.
Just for the book, "TCU" is "Transmitter Coupling Unit" and "ATU" is "Antenna Coupling Unit."
While searching for useful frequencies many of us use radio-locator.com, where all the licensed stations are listed.
As we've found this morning, they also list some CC stations.
http://www.radio-locator.com/info/KJAK-CC