From: military-radio-guy Full-Name: Dennis R Starks To: military radio collectors#2 Fcc: Sent Date: Wed, 26 May 1999 06:32:50 Subject: MILITARY COLLECTOR GROUP POST, May 26/99 Message-ID: <19990526.063154.5239.5.military-radio-guy@juno.com> X-Status: Sent X-Mailer: Juno 1.49 MILITARY COLLECTOR GROUP POST, May 26/99 Index: MORE INVERTER CONTROL IDEAS; from Ray Robinson SPECIAL EVENT REPORT; Aberdeen Proving Grounds MEMBERS WRITE; ARC-5 Web Page Up, HUMOR; *********************************************** MORE INVERTER CONTROL IDEAS; from Ray Robinson Hi Dennis, To continue my reed fetish, here is an idea for those that use a battery for the LT and an inverter for the HT. The simple circuit can be obtained from http://www.shlrc.mq.edu.au/~robinson/museum click "information" Regards Ray vk2ilv P.S. Also worth considering, is mounting a reed close to the skin of the radio case, and using a fridge magnet to turn it on. It will work better through non ferrous materials, but may need to be attached somehow. I have a diving torch, that is rated for 100 meters depth, and the switch moves a magnet over a reed to energise it. There is no case penetration for the switch and so the case waterproofing is easier. However, the case is plastic, so magnetic fields pass through unattenuated. --------------------------------------------------- AUTOMATIC CONTROL OF AN INVERTER An inverter power supply can be controlled automatically with a reed, sensing the filament current. When a valve radio has an inverter to supply the high tension, but uses batteries for the low tension, it is difficult to turn the inverter on and off conveniently. Unless it is turned off, when not required, the quiescent current will drain the battery over time. It is not always easy or desirable to modify the radio. A circuit to sense the filament current and turn the inverter on is useful. The circuit should draw no current until the radio is switched on. The use of a conventional relay is not suitable, as relay coils are designed to operate on fixed voltages. A relay coil that operates using current is required. Use a reed relay (which has normally open contacts) to supply the voltage to the inverter. When the reed is open, the inverter is not powered and so there is no current drain. The reed is activated by the filament current. Method A low resistance coil is placed between the battery and the radio's filament input. When the ON/OFF switch in the radio is in the OFF position (switch open), no current will flow through the reed coil and so nothing happens. When the radio is switched ON, the filaments are connected in series with the reed coil, which will close the contacts and energise the inverter. When the radio is switched OFF, no current will flow through the reed coil to the filaments, and the reed will switch the inverter off. A series of reeds are available for use in burglar alarm systems. They are a slim glass tube containing contacts that are activated by a magnetic field. They are intended to be activated by a magnet being in close proximity to them. The magnet and reed are usually placed on a door or window, such that when it is opened, the reed contact opens and triggers the alarm. The reed is usually specified by the contact rating and the activating magnetic field, often in Ampere/Turns (AT). The reeds I have used are 500 ma contacts, 60 AT, and 1 amp contacts, 120 AT. These are inexpensive. There are many others available. There are two things to consider when winding the coil for the reed, the number of turns and the coil resistance. The number of turns simply depends on the filament current. If the radio draws 1 amp, then you need a coil with 120 turns for the 120 AT reed (in theory). The coil resistance is important. You have to use thick wire to ensure that there is minimum voltage drop across the coil, as it is in series with the battery. If you are using a 1.5 volt battery, then the coil should not loose more than 0.1 volts. I used 0.7 mm diameter enamel copper wire and wound 100 turns on a former, such that it was a close fit to the 1 amp reed. I made it long enough to cover the whole reed up to the end pinches. It used 3 layers with no intervening insulation and then I painted it with clear nail lacquer. It activated the large reed with 1.6 amps (i.e. 160 AT) for a 0.18 volts drop, and the small reed at 0.6 amps (i.e. 60 AT) with 0.05 volts drop. I made a larger diameter coil using an aerial coil former, and wound 120 turns in 2 layers. This coil activated the large reed at 0.6 amps (i.e. 72 AT) for a 0.16 volts drop, and the small reed at 0.3 amps (i.e. 36 AT) with 0.10 volts drop. I found that with the larger diameter former, the voltage drop was greater due to the larger amount of wire used. I also found that the AT requirement, to activate the reed varied with different coil designs. There are a variety of reeds available. The Radio Spares catalogue lists the 6RSRA which has 0.5 amp contacts and 40 AT activation, and the DRG200 which has 1.3 amp contacts and 80 AT activation. These are considerably better than those I used in the tests. Testing I have tested this circuit using a power supply with an adjustable current limit, with the current set to just above the reed activating threshold. I have used a lamp as a load. I have run this continuously for 24 hours. I have also had a timer circuit (555 timer IC and a relay) that turned it on for 1 second and off for 1 second, for 48 hours. It continued to function OK. Conclusion The advantages of this circuit are that you can use the radio's ON/OFF switch to turn the filament volts on (and consequently the HT inverter) without modifying the radio. There is no current drain when the radio is switched off. The disadvantages of this circuit are that there is a voltage drop across the relay coil. End ed) the idea of using reed switches and magnets is not a new one to the military. This method was considered for tx/rec control during the development of the PRT-4. The R-1410/GR(XE-2) uses magnets on it's bands selector, and bandwidth switches. The magnets are connected to a longer rotary switch shaft, and are swung across a pair of read switches at the back of the radio to change filters in the IF. he system worked well until over time the glue that secured the magnets deteriorated and the magnets would fall off jamming up the skunk works. *********************************************** SPECIAL EVENT REPORT; Aberdeen Proving Grounds Event: Aberdeen, Md - - - East Coast Military Rally Location: Aberdeen Proving Grounds Situation: Every military nut for miles arounds shows up, lots of story telling, equipment trading, beer guzzling. Military Vehicles abound. Weather: Excellent, except for Wednesday which was a wash out. Special Dignataries Noted: Surplus Al W3UGD, Jeff Ciccone WA2YOJ Narrative Thursday: I left my home base Dover, Delaware on Thursday at 0545 hours in my Chevy "CommoVan", the plan was to do a quick recon on Thursday and then drive my M-151 up on Friday and setup real "working radios". Thursday was pretty much of a radio bust but did manage to add a survival radio to my collection and found a PRC-6 for $10 that had 50.9 Mcs crystals in it. The URC-11 was complete with a BA-1315 battery and was working. The troop that examined the radio prior to me tried it out and send out the beacon on 243.0 mcs(I dont do megahertzies), you could hear it(the beacon) from the case. He did it several times before I could get the radio out of his hand. Once I had the radio in my hand had to buy it. Then ran into Surplus AL and he was doing a brisk business selling manuals, connectors etc. Bought a lot of RF adapters from him for an excellent price. AL extended the invitation to set up next to him if I came back on Friday and I accepted. Narrative Friday: Departed Dover Delaware at 0530 with the M-151. During my preflight at 2100 hours the evening before I found that the valve in the left tire was not a valve , it would not let any air in or out The tire seemed to be full so I elected not to change any thing, I could not get the valve to unscrew. But decided to download some of the equipment to lighten the load. On my AM departure I had to wear a Watch Hat and M-65 jacket, cool breeze floating in from the ocean and I didnt have any doors or curtains on the jeep. Lonely driving North early in the morning, nothing but jeep sounds, those knobby tires hitting the pavement, sort of a buzzing sound. Approx 45 minutes out, U joint on the front right side started to make clicking sound, since the shaft was just free wheeling, press on. The jeep had ran fine the weekend before at the Dover Air Show, but now we were on a real cross country mission. Got to rendevous with Surplus AL and show the Feather Merchants some real radio operation. Stopped in Elton Maryland at MacDonalds, quick snack and had to let several kids sit in jeep. On to Aberdeen, click, click, click, the U Joint sounds nagging at me, also listening for air to exit from front left tire. Gas gage now going up and down, up and down, all most hitting the stops of the gage, plenty of gas but evidently the pot(variable resistor) in the tank was bad. What keep the gas tank from blowing up with the variable resistor making sparks in the middle of the gas, never have understood this, any way pressing on. Arrived at Aberdeen, finally found the encampment area, dodging beer cans on the street as I approach the encampment area, drive around and find Surplus AL, he is happy to see me and I place the Jeep in a strategic spot that I chose the day before during my recon run to get shade from a tree but still get the antennas partially in the clear. I dont unpack right away as I want to hit the flea market. Found a GRC-9, with canvas cover, cables, mint condition for $135, owner promises me that he will find the vehicle mount kit etc. Then I saw a RS-6 complete, even had a handcrank generator cable which I had not seen before. Started walking around, in my years of hamfesting I have never seen so much green radio equipment. But prices in general were high. The sad part is I saw no World War Two equpment or very much Korean war equipment. Only saw one small Russian piece which was a power supply, looked like aircraft stuff. But there was a lot of it. Returned to Surplus AL's site, he is doing a brisk business, mostly manuals, and he had a lot of em, every Manual needed from Search Lights to PRC-6's. Start talking to AL and for the first time that I have known him find out that he was awarded a Purple Heart, I am stunned. After a while I sat up. I ran a GRC-109 on 7.038 CW and it worked out fairly well, using a 20 foot vertical and the jeep ground via a slave connector. Also ran a PRC-47 which is on a mobile mount in the jeep. A GRC-9 was also used, using a "inverter power supply from a GE exec" one radio and it worked very well powering the GRC-9 and the GRC-109 transmitter. The CW sounds stabbed the air, the sounds floated across the encampment and lot of folks showed up, courious, asking questions, many had been radio ops in Viet Nam , looks of SF guys, lots of em, ran their fingers over the equipment, bringing back the memories of the camps and the reports to Saigon. Al came over and picked up the key and started pounded out a CQ, the receiver was slightly overloaded but I turned up the volumn as the crowd gathered. We worked up and down the East Coast on a North South path, not much on 40 to the West. Jeff Ciccone WA2YOJ drops in, invites me up to the "stealth jeep". I leave AL to man my site and his and visit jeff. Jeff has so much equipment, its hard to mention it all, and its all new stuff that I am not familiar with it, anyway he is the Official East Coast Green Radio Czar, the king, I gave him first place for "radio jeeps" but I was unofficial second. Anyway back to Surplus Al's site and my jeep. Stayed on 40 meters, band was dropping in and out. Jeff comes back, people are asking questions about installing equipment in there military vehicles, mostly jeeps, one guy even brings his jeep over- - - Jeff patiently explains what is needed and how to operate the equipment, What a green radio ambasador! I break out my two PRC-71's, ask lots of folks if they have seen the radio and if they KNOW WHERE A MANUAL IS LOCATED, no one knows , its like the radio does not exist. Tried out a couple of crystals for the PRC-71 ordered from JAN crystals for a load cap of UUFD( pf to the new guys)(I don't like to recognize pf's) Crystals worked great and were close to frequency. Worked the 71's for a while on forty and then set them up in the phone band so that the feather merchants and straight leggers could try out SSB or CW, used small antennas with a 50 ohm resistor built into the antenna to keep the RF radiation range down. 1700 hours, pack up, bid AL a farewell, he comes over to the jeep like he is worried about me and probably with good reason, tell him I will be careful etc. I give Al my last softdrink out of my cooler and wish him luck with the on coming evening, it will get cold.Lonely under the tree. On the road, click, click, click, click, the U joint talking to me. Trucks passing me at 75 MPH, tourist honking their horns because I am to slow, to slo to slo. Kids in the back seat waving. Gas gage going up and down, its making me nervious, I don't get nervious but pull over and pull the wire out of its connection, now the gage is steady, empty is the reading but steady. Click click click, Finally get to the home barn three hours later. END OF REPORT Respectfully Breck Smith K4CHE, Dover DELAWARE ed) Damn good narative. Glad to see that I'm not the only one who has mechanical troubles. Good thing though that I always have Ike close in tow with radio comms. He's had to bail me out several times now. Maybe someday soon that POS Ford mini-van of his will crap out, and I'll get to return the effort. I disappointed him though on our last long range excursion. Nothing broke, and I had affixed two spare tires, and two five gallon Jerry cans of extra gas to the Power Wagon. Didn't you get a PRC-71 from Alan during the last Library manual exchange? I just got mine with many thanks! It would seem that some of our Dayton member/attendees are not the gifted scrounger/reporters they should be. Ike came away with amoung other things, a newish GRC-9 with ALL it's accessories, including gen, canvas, ants, DY-88 etc. for $150. George R. got a PRM-10 grid dip meter, a ZM-11 bridge and an URM-10, URM-127 audio generator (total cost $50). Wake up people, there's stuff under those tables too. *********************************************** MEMBERS WRITE; ARC-5 Web Page Up, Dewayne Moore's fine ARC-5 web pages are back on line at my arc5.com domain. Check them out at: http://www.arc5.com/duck/ I'm working on updating some of the links. Some day I might even get my own pages going... Stranger things have happened ;-) 73 DE Dave AB5S *********************************************** HUMOR; Subject: UPCOMING MASTERCARD COMMERCIAL Lockheed F-16 Fighting Falcon - $25 million dollars Lockheed F-117 Nighthawk Stealth Bomber - $45 million dollars. Boeing B-52 Stratofortress - $74 million dollars. Brand new B-2 Stealth Bomber - $2.1 billion dollars. A decent map of downtown Belgrade. -- Priceless. There are some things that money can't buy... unfortunately good intelligence isn't one of them. (unless you're at Los Alamos) For the rest, there's MasterCard, the official card of the 19 member NATO alliance and those who believe that sometimes you just need to blow up something in order to restore peace. And start WWIII with a few billion Chinese. ----------------------------------------------------------------- A new service is now available at the Pentagon. Thank you for calling the United States Military. I'm sorry, but all of our units are out at the moment, or are otherwise engaged. Please leave a message with your country, name of organization, the region, the specific crisis, and a number at which we can call you. As soon as we have sorted out the Balkans, Iraq, Korea, China, the Y2K Bug, marching up and down the streets of Washington, D.C., and compulsory "Consideration Of Others" training, we will return your call. Please speak after the tone, or if you require more options, please listen to the following numbers: If your concern is distant, with a temperate climate and good hotels, and can be solved by one or two low risk, high altitude bombing runs, please press 2 for the United States Air Force. Please note this service is not available after 1630 hours, or on weekends. Special consideration will be given to customers requiring satellite or stealth technology who can provide additional research and development funding. If your crisis is small, and close to the sea, press 1 for the United States Marine Corps. If your inquiry concerns a situation which can be resolved by a bit of gray funnel, bunting, flags and a really good marching band, please write, well in advance, to the United States Navy. Please note that Tomahawk missile service is extremely limited and will be provided on a first come, first served basis. If your inquiry is not urgent, please press 3 for the Rapid Deployment Force. If you are in real hot trouble, please press 4, and your call will be routed to the United States Army Special Operations Command. Please note that a compulsory credit check will be required to ensure you can afford the inherent TDY costs. Also be aware that USASOC may bill your account at any time and is not required to tell you why, as it will be classified. Have a pleasant day, and thank you again for trying to contact the United States Military. ----------------------------------------------------------------- EXPERIENCING NAVY LIFE (Ohhh sooo true!) To experience Navy life, try a couple of these - right in the comfort of your own homes. 1. Buy a dumpster, paint it gray and live in it for 6 months straight. 2. Run all of the piping and wires inside your house on the outside of the walls. 3. Pump 10 inches of nasty, crappy water into your basement, then pump it out, clean up, and paint the basement "deck gray." 4. Every couple of weeks, dress up in your best clothes and go the scummiest part of town, find the most run down, trashy bar you can, pay $10 per beer until you're hammered, then walk home in the freezing cold. 5. Perform a weekly disassembly and inspection of your lawnmower. 6. On Mondays, Wednesdays, and Fridays turn your water temperature up to 200 degrees, then on Tuesday and Thursday turn it down to 10 degrees. On Saturdays, and Sundays declare to your entire family that they used too much water during the week, so all showering is secured. 7. Raise your bed to within 6 inches of the ceiling. 8. Have your next door neighbor come over each day at 5am, and blow a whistle so loud that Helen Keller could hear it and shout "Reveille, Reveille, all hands heave out and trice up." 9. Have your mother-in-law write down everything she's going to do the following day, then have her make you stand at attention in the back yard at 6 AM and read it to you. 10. Eat the raunchiest Mexican food you can find for three days straight, then lock the bathroom door for 12 hours, and hang a sign on it that reads "Secured - contact OA DIV at X-3053." 11. Submit a request form to your father-in-law, asking if it's OK for you to leave your house before 3 PM. 12. Invite 200 of your not-so-closest friends to come over, then board up all the windows and doors to your house for 6 months. After the 6 months is up, take down the boards, and since you're on duty, wave at your friends and family through the front window of your home. You can't leave until the next day. 13. Shower with above-mentioned friends. Try not to drop your soap. 14. Make your family qualify to operate all the appliances in your home (i.e. Dishwasher operator, blender technician, etc). 15. Walk around your car for 4 hours checking the tire pressure every fifteen minutes. 16. Sit in your car and let it run for 4 hours before going anywhere. This is to ensure your engine is properly "lit off". 17. Empty all the garbage bins in your house, and sweep your driveway 3 times a day, whether they need it or not. 18. Repaint your entire house once a month. 19. Cook all of your food blindfolded, groping for any spice and seasoning you can get your hands on. 20. Have your neighbor collect all your mail and deliver it to you once a month, randomly losing every 5th item. 21. Spend $20,000 on a satellite system for your TV, but only watch CNN and the Weather Channel. 22. Have your 5-year-old cousin give you a haircut with goat shears. 23. Sew back pockets to the front of your pants. 24. Spend 2 weeks in the red-light districts of Europe, and call it "world travel." 25. Attempt to spend 5 years working at McDonald's, and NOT get promoted. 26. Needle gun the aluminum siding on your house after your neighbors have gone to bed. ----------------------------------------------------------------- Best newspaper headlines of the year 1. Include Your Children When Baking Cookies 2. Something Went Wrong in Jet Crash, Experts Say 3. Police Begin Campaign to Run Down Jaywalkers 4. Drunks Get Nine Months in Violin Case 5. Iraqi Head Seeks Arms 6. Is There a Ring of Debris Around Uranus? 7. Prostitutes Appeal to Pope 8. Panda Mating Fails; Veterinarian Takes Over 9. British Left Waffles on Falkland Islands 10. Teacher Strikes Idle Kids 11. Clinton Wins Budget; More Lies Ahead 12. Plane Too Close to Ground, Crash Probe Told 13. Miners Refuse to Work After Death 14. Juvenile Court to Try Shooting Defendant 15. Stolen Painting Found By Tree 16. Two Sisters Reunited After 18 Years in Checkout Counter 17. War Dims Hope for Peace 18. If Strike Isn't Settled Quickly, It May Last a While 19. Couple Slain; Police Suspect Homicide 20. Man Struck By Lightning Faces Battery Charge 21. New Study of Obesity Looks for Larger Test Group 22. Astronaut Takes Blame for Gas in Space 23. Kids Make Nutritious Snacks 24. Local High School Dropouts Cut in Half 25. Typhoon Rips through Cemetery; Hundreds Dead *********************************************** The preceding was a product of the"Military Collector Group Post", an international email magazine dedicated to the preservation of history and the equipment that made it. Unlimited circulation of this material is authorized so long as the proper credits to the original authors, and publisher or this group are included. For more information concerning this group or membership contact Dennis Starks at, . A list of selected articles of interest to members can be seen at: http://www.softcom.net/users/buzz/backmail.html ***********************************************