Battleship Iowa's "Original" 1980's Transmitters Possibly ON-THE-AIR This Coming Wednesday!

WELL....it's been a long, slow, slog, but we're 90+% there.

We have two "Red Phones" mapped out through the "Coke Machine", the audio interface boxes, the transmit and receive switchboards, and the R-1051 receivers and the AN/URT-23A transmitters.

We've verified that we have correct receive audio through the receive path, and the transmit audio from the "Red Phones" also makes it down to the Transmitter Room, and drive the #3 transmitter to full (1000 Watts +) power into a dummy load.

For the receive antennas we're using the "Twin Whips" mounted up on the bridge, and for transmit, we'll be using the "Goal Post" or "Bull's Horns" antenna located just forward of the #2 stack. The "Goal Post" antenna is fed with (I think) 3-1/2" Heliax cable from the transmitter room, and some time ago I made up an adapter that connected the Andrew flange to a Type-N female so we could run coax into one of the large antenna couplers down in the transmit room.

I used my Comet CAA-500 Antenna Analyzer to verify that adjusting the controls on the coupler caused the impedance to vary, and the manner in which it varied it varied in "looked" just like we were tuning a random length antenna with a good old Johnson Matchbox.


The players are as follows:



A "Red Phone":

The Infamous "Coke Machine":

R-1051 Receiver:

Receive Antenna Couplers:

"Twin Whips" Receive Antennas:

AN/URT-23 Transmitter:

Transmit Antenna Coupler(s):

"Goal Post" Transmit Antenna:

I'm posting this early so those who are interested in trying work us will have plenty of time to get ready. We know we transmit better than we receive, even running 100 Watts from the Amateur Radio gear, so please be patient with us if we manage to make this happen.

Not all of us are "Contest Operators", so pile-ups will be dealt with "Loudest Heard First", and then we'll try to get to the weaker stations.

Look for us in the upper half of the General section of the 20 Meter phone band. *IF* we get the gear On-The-Air, it will be after 2000 UTC, and before 2359 UTC.

We'll be using an individual's callsign, not NI6BB, and we'll include "Battleship Iowa" in all our CQ's.

Hope to see you On The Air!


I'll have my tablet computer with me, so if this is a "GO!", I'll make a post here right before we go live OTA.

Antenna Work, Part II

OK, so I dropped the antenna down today, and swapped out my homebrew PVC adapter for the OEM metal version.

I took a bunch of pictures....BUT.....I had my camera set wrong, and the pix came out so overexposed that I couldn't even save them with GIMP.

So, all I have to show are some before and after plots, and those didn't covert very well, either.

Here's the 2 Meter VSWR graph with the plastic mounting:

And here it is with the OEM metal mounting:

Here's the 70cm plot wth plastic:

And here's the plot with the OEM metal mount:

Sorry for the terrible size disparity with the plots. I had to "print to file" on the Windoze machine, then convert them to png's on the Linux machine, and the "print to file" utility that creates the pdf dows whacky stuff.

I have the Linux version of the capture/display software for my AA-520 analyzer, and I think it's high time I install it, and learn to use it!

ANYWAY......the plastic vs metal plots don't look much different, so I'm not expecting much difference in performance. I called "CQ" on our "club-comm" frequency of 145.510, but couldn't raise anybody on either radio, so I assume they're all busy tonight.

Now one thing kind of jumps out at me, and that's how FLAT the VSWR curve is on 2 Meters. That kind of "flatness" over a wider bandwidth than the antenna is rated for can be indicative of an excessively lossy feedline.

I'm going to run some plots on the little GP-1 antenna, and see if it looks more like the published curves. I physically inspected the feedline on the GP-3 today, and there's no external evidence of damage to it, the PL-259's are properly soldered and the one at the antenna was still nice and shiny and clean after I took the tape off of it.

Yeah, I know, I should have made some loss measurements, but I got clobbered with some Honey Dews right in the middle of this today.

It's an easy 10-minute job to lower the antenna and disconnect the coax, so if the plots on the GP-1 look like the ones Comet publishes, I have a feeling I'll be dropping the GP-3 down again on Monday......