[MRCA] [ARC5] Reading Airshow AAR
Tim
timsamm at gmail.com
Sat Jun 13 12:09:14 EDT 2026
Good on ya Mark ..That's a lot of work....You're showing the rest of us how
it's done...
BZ!
Tim
N6CC
On Sat, Jun 13, 2026 at 8:22 AM Mark K3MSB via ARC5 <arc5 at mailman.qth.net>
wrote:
> Here's my attempt at a somewhat decent AAR.....
>
> [image: image.png]
>
> [image: image.png]
>
> I spent 4 days at the Mid Atlantic Air Museum's World War II weekend as
> part of a regional reenactor group. Setup was Thursday June 4th with the
> event running Friday June 5th through Sunday June 7th.
>
> This was my second time at Reading as part of the reenactor group, and the
> start of my second year of reenacting in general. Weather was hot and
> somewhat humid, but I had a nice breeze through the Comms Tent on all three
> days.
>
> It was great to see the B-17 “Sentimental Journey” in the skies over
> Reading, as well as the A-26 Invader “Silver Dragon”.
>
> Overall, I had a steady stream of visitors in the Comms Tent all three
> days, and did numerous demos each day.
>
> Objectives:
> Educate people on the HF / VHF radios used on Allied Aircraft in WW II.
> Describe the differences between the SCR-274N Command Radios and SCR-287
> Liaison radios.
> Demonstrate how a DF unit works.
> Demonstrate a BC-611.
> Explain that during the Battle of Britain, the British not only had to
> determine the position and speed of the German aircraft, but also of the
> British aircraft in order to formulate a least time / least fuel intercept
> solution.
>
>
> Equipment used:
> SCR-274N system. Working on 40 & 75M AM. 40/80 TX, 40/80/LF RX. New
> this year were two remote tuning cables and a new Pilots Control box that
> was in better shape than my old one. Powered by a pair of 12V 100 AH
> Lifepo4 batteries in series. Dynamotors used for the transmitter and
> receivers.
>
> SCR-287 System. The BC-375 and 2 additional tuning units were static
> display only. The BC-348Q was working and has it's original dynamotor.
> Powered by a pair of 12V lawn tractor batteries in series.
>
> DF Setup consisting of a DU-1 and an ATA CBY-46145 Broadcast Band
> Navigation Receiver. Due to the lack of NDBs in the area, I did not
> attempt to use my BC-453 Beacon Band Navigation Receiver this year. The
> BC-453 was in the SCR-274N rack. The ATA receiver used a dynamotor. It
> was powered by a pair of 12V lawn tractor batteries in series (the same
> ones used for the BC-348Q). HV for the DU-1 was obtained from the center
> connector of the ATA receiver.
>
> BC-611. Working on 75M AM. Used 4 D batteries and the DC-DC converter
> that used to be made by the Italian fellow. Worked well!
>
> SCR-522 VHF system with BC-608 Pipsqueak unit – Display only.
>
> Setchell Carlson BC-1206 LF Receiver. Display only.
>
> MN-36 Loop Antenna. Display only.
>
> BC-221 Frequency Meter. Display only.
>
>
> What did I expect to happen:
> Use the HF radios to talk to others at the event;
> Use the DU-1 and associated receiver to illustrate how an aircraft found
> it's position by the DF process.
> Use the HF radios to “talk to each other” during demos.
>
> What Happened:
> I made two BC-611 to BC-611 contacts with Mark WW2RDO who was also at the
> event.
> I made one contact with Don K3OP with my SCR-274N. He was in the parking
> lot with a TS-480.
> All three contacts were on 75M AM.
>
> Demos of the DF setup, BC-611, and SCR-274N worked extremely well and was
> well received.
>
>
> What went well and why:
>
> The DF demo went well. I had the ATA receiver tuned to an AM broadcast
> station about 50 miles away. I explained how the operator would manually
> turn the DU-1 loop to find the maximum signal then report the bearing to
> the pilot (yes, I know they went for the null, but I didn't think that
> detail was relevant for my purposes). I explained that the DU-1 loop was
> normally mounted on the fuselage with an extension shaft to the operator's
> table, and I showed them the scales the radio operator used to determine
> the bearing to the station. I had an MN-36 Football next to the DU-1 for
> static display, and I explained that there was a loop inside the MN-36 that
> was motorized and worked the same way as the manual DU-1.
>
> I then mentioned that our equipment tent has a Gibson Girl and explained
> what it did, how it was used, and that downed crews were found using the
> same DF process from land bases or flying boats. I explained these were
> examples of “Passive DF”. I then explained how the SCR-247N could be used
> by a lost pilot to get a bearing to a known ground station by pushing the
> transmit button on the Transmitter Control Box in order for a ground
> station to give a pilot a bearing to the station.
>
> I explained the function of the Command sets (short range air to ground /
> air to air) and contrasted that to the function of the Liaison radios
> (long distance). I showed them the inside of a command receiver as many of
> the younger people had never seen a vacuum tube. I explained what each
> box did and how they could be located in different parts of the airplane,
> and what the pilot's receiver and transmitter control boxes did.
>
> Demos were varied.
> Transmit on the 274N and listen to the signal on the 274N receiver or the
> BC-348Q.
> Transmit on the BC-611 and listen to the signal on the 274N receiver or
> the BC-348Q.
> Feedback considerations aside, these demos worked fine and were well
> received by the visitors.
>
> The SCR-247N was on 3885. Last year, my antenna was a 45 foot wire that
> exited the CommsTent, went over the top and down the other side, then ran
> parallel to ground around the perimeter of the tent at a height of just
> over 6 feet. This year, I used a Hustler 75M Mobile antenna attached to
> one of my wife's biggest baking pan (yes, with prior approval....you don't
> get to be married for 44 years without asking about something like this
> first....). The assembly was hidden behind a canvas partition in another
> part of the tent. A counterpoise was used. Matching was accomplished by
> my custom box of a 4:1 UNUN and series matching capacitor and MFJ Tuner.
> Matching was not a problem
>
> I explained the use of the BC-221 Frequency Meter and explained how all
> the various radios were netted to the mission frequencies before a mission.
>
> I explained the use of the SCR-522 and how it was used alongside the
> SCR-274N and SCR-287 radios. I had the BC-608 “Pipsqueak” unit running and
> explained that this was used to aid the British in determining the position
> of their own aircraft. I explained that every minute for 14 seconds, the
> Pipsqueak would cause the SCR-522 to send out a signal, and the ground
> stations would DF (triangulate) on the signals to get an accurate position
> of the Spitfires, Hurricanes, etc. That position, combined with known
> winds at altitude and the specific performance of the various aircraft
> types, the best intercept solution to intercept the German aircraft would
> be determined. Explained this was pre IFF. Most visitors had no idea the
> British had to do this. My goal was to get the visitors to understand the
> complexity of how the British got their planes to intercept the Germans;
> it was a LOT more complicated than “Go East young man”....... and the
> computations were done without computers!
>
> To tune and net the SCR-274N each morning, I had an ICOM transceiver in a
> plastic container under a canvas tarp on the bottom shelf of my big table.
> Day to day tuning of the antenna was minimal, and surprisingly the radios
> held frequency very well day to day. Netting the SCR-247N TX to 3885 was
> quick using the ICOMs band-scope.
>
> What can be improved and how?
>
> Antenna for the SCR-274N. The mobile whip worked OK, but others not on
> the field were unable to hear me at the appointed times. And, since I was
> making short transmissions during my demos (with proper FCC ID.....) that
> may be a good thing. I need to get a wire antenna vertically up through
> the top of the tent then horizontally to another tent. There are
> non-technical reasons why this is a challenge, but I will try again next
> time. I enjoy POTA (Parks on the Air) and I use a 55 foot wire to a 9:1
> balun for 40M. No counterpoise, and it works very well. I'm doing to try
> that on 80M as well. Try as I might, I've never gotten a 274N
> transmitter to work directly to a wire regardless of using a counterpoise
> or not. This is why I go from the 274N via a 4:1 UNUN and series matching
> capacitor into the MFJ tuner; I can get 50 ohms unbalanced into the tuner
> and let the MFJ handle matching whatever I put on the other end. The
> visitors never see this stuff.
>
> Build a DC-DC converter for the BC-221 so I can actually demo it. It
> currently runs off of 110 VAC and that doesn't do me any good in the field.
>
> Get dud tubes for the BC-375 to display them.
>
> Have a code practice oscillator available for the young kids to play with.
>
> My mic for the SCR-274N went belly up on Sunday afternoon. Bring a second
> mic.
>
> Conclusion / comments
>
> Being able to demo the SCR-274N and BC-611 at will for people was a huge
> success. Most people assumed that radios were just replicas until I turned
> on the SCR-274N and they heard the dynamotors spin up. “You mean this
> stuff works?”..... “Yup, let me show you”....
>
> My setup was well received by young people. I had kids turn the DF loop
> if they wanted to for a “hands on” experience.
>
> A father and daughter came into the tent. He said his father (her
> grandfather) was a radio operator on a B-17 during the war. I told them
> the radios I had were the ones he would have used. After I gave them a
> demo, I noted some tears starting to form in the granddaughters eyes.
> Encounters like this make all the time and aggravation of getting these
> radios restored and working in the field worth it. We talked for quite a
> few minutes afterwards.
>
> A young girl, maybe a teenager, came in and I gave her a demo. She then
> asked me “that's good, but how do you address the battery issue on the
> BC-611? They can't be good after so many years”. I said that was a great
> observation and told her about the DC-DC converter inside the unit. We
> talked a bit more about restoration and she then said she enjoys restoring
> first generation computers and runs into some of the same kinds of problems
> I run into. OK, she's not restoring radios, but she is restoring! That's
> a start!
>
> Saturday night around sunset we had weather warnings about a severe squall
> line that was approaching. Heavy rain and strong winds, but the line was
> pretty narrow. Each night I cover my radios with a vinyl tarp, even
> though the radios are in a zipped canvass tent. The tent is old and
> leaks a bit..... So, I got the tarp over the radios and we secured the
> tent, double checked the tie downs etc. The squall line hit and the
> winds were strong. All of sudden people were yelling as one of the main
> sleeping tents that housed about 10 cots and people's belongings went
> airborne. Apparently wind got under the tent. So, it was all hands on
> deck to get the tent back over people's belongings and we sat on the tent
> getting drenched to the skin for several minutes. We spent about an hour
> afterwards helping to get the tent back up.... all was completely soaked.
>
> Afterwards I realized that in the Comms tent, under the vinyl tarp, in a
> tight plastic box, in a small canvas bag.... was my poncho..... nice and
> dry.....
>
> 73 Mark K3MSB
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