rydeyz Posted June 7, 2010 Share Posted June 7, 2010 Have any of you ever heard UHF transmissions on your VHF radio? Generally only occurs when the UHF freq is double the VHF freq. (VHF @ 122; UHF @ 244) Even if you haven't experienced it, you can throw out any info you've got! Quote Link to comment Share on other sites More sharing options...
tinyclark Posted June 7, 2010 Share Posted June 7, 2010 Yes, it's called a harmonic. That's just the way it is, there's no magic to it. That's why the ELT transmits at 121.5 only. It's also picked up on 243, the first harmonic. If you transmit on say 121.000, you can pick it up on UHF 363.000, the second harmonic. Quote Link to comment Share on other sites More sharing options...
donwon Posted June 7, 2010 Share Posted June 7, 2010 I heard about that back in the early 70,s. I only had the money to tinker with CB radios but I learned to make some killer antinnas. I used old tube tipe radios back then. I cophased 2 antinnas made of .o32 safety wire that would out talk anything I had ever heard of back then. Each had 204" of wire on them and hooked up to a 25 watt 10 channel blackface Johnson tube tipe radio. I could switch the transmit and receave christals around and get on a frequency lower than the CB. The problem was getting someone to talk to me. It was illigle for the Ham operators to talk to me but every now and then some of them would. I think I still got 2 of them radios packed back in boxes somewhere. All one of them needs is a modulation tube. It put out 25 watts last time I used it. Quote Link to comment Share on other sites More sharing options...
donwon Posted June 7, 2010 Share Posted June 7, 2010 I heard about that back in the early 70,s. I only had the money to tinker with CB radios but I learned to make some killer antennas. I used old tube type radios back then. I co-phased 2 antennas made of .o32 safety wire that would out talk anything I had ever heard of back then. Each had 204" of wire on them and hooked up to a 25 watt 10 channel black-face Johnson tube type radio. I could switch the transmit and receive crystals around and get on a frequency lower than the CB. The problem was getting someone to talk to me. It was illegal for the Ham operators to talk to me but every now and then some of them would. I think I still got 2 of them radios packed back in boxes somewhere. All one of them needs is a modulation tube. It put out 25 watts last time I used it. Quote Link to comment Share on other sites More sharing options...
rydeyz Posted June 7, 2010 Author Share Posted June 7, 2010 Yes, it's called a harmonic. That's just the way it is, there's no magic to it. That's why the ELT transmits at 121.5 only. It's also picked up on 243, the first harmonic. If you transmit on say 121.000, you can pick it up on UHF 363.000, the second harmonic. You know, I almost just called you directly, but I figured I'd poll the audience... Well, that and to make this a little more widely known. But can you explain the math there? B/c I understand the guard freqs, 243 is double 121.5, but how does 121 come out on 363? Quote Link to comment Share on other sites More sharing options...
Coaster Posted June 7, 2010 Share Posted June 7, 2010 my math might be a little rusty but I think 121+121+121=363 Quote Link to comment Share on other sites More sharing options...
tinyclark Posted June 7, 2010 Share Posted June 7, 2010 Eggsactly, it's the second harmonic of 121, the first is 242, the second is 363, the third is 484. Each harmonic is much weaker than the original frequency. The harmonics also work in reverse, Half of UHF 263 would be 131.5. The next time you are out on an airplane, try this. transmit on HF at 10 MHZ with the VOR on. If I remember correctly, all the marker beacon lights will come on. 10 MHZ is the IF freq of the MB receiver. Oh yea, HF 27.185 is channel 19 on the CB. Quote Link to comment Share on other sites More sharing options...
INS/Dopplertroop Posted June 8, 2010 Share Posted June 8, 2010 Talk about CB 19. There have been incidents, I heard tell (maybe even seen tell), usually mid shift incidents, when the 18 wheelers rolling down Del U.S. 113, passed Dover AFB, would get a "Breaker-Breaker 1-9" that would peg their meters and darn near knock their doors off once in a blue moon. That always seem to raise a stink with Comm Sqdn Freq managers. Always got a "Holy Sh-- what was that?" out of the truckers too. Quote Link to comment Share on other sites More sharing options...
INS/Dopplertroop Posted June 8, 2010 Share Posted June 8, 2010 I'll tell you too. Being able to tune in some music on the ADF when working an all night problem or just waitin for parts, the truck, etc. sure was nice. Quote Link to comment Share on other sites More sharing options...
tinyclark Posted June 8, 2010 Share Posted June 8, 2010 The radio was better on a C141, as there was a speaker in the fligth deck. We used to listen to AFN sports in Germany. The tuner of the DFA-73 was a bit better than the ARN-6, it had transistors. I still can't believe we have systems with vacuum tubes on our aircraft. It's a frikkin' travesty. But hey, we do have blue force tracker, SADL, Whizbang-the-crap-out-of-it-to display-it-on-the-RADAR-screen and do a temp install. If we could buy a frikkin vowel, or a war, it would be nice. Quote Link to comment Share on other sites More sharing options...
KF4DVG Posted June 8, 2010 Share Posted June 8, 2010 I'll tell you too. Being able to tune in some music on the ADF when working an all night problem or just waitin for parts, the truck, etc. sure was nice. .... or listening to FEN AFRTS on the ARN-6 over the PA while working a priority C-130 (gray bird) after a heavy snow at Yokota...an announcement.... "the following offices are closed due to inclement wx ....CBPO (now MPF), Finance, flight line chow hall, etc....." Tromping thru shin high wet snow was so awesome while trying to fix a pressure feed thru coax connector for the marker beacon in the left main wheel well. A heater was no good, only made things wetter! Bob Quote Link to comment Share on other sites More sharing options...
INS/Dopplertroop Posted June 8, 2010 Share Posted June 8, 2010 .... or listening to FEN AFRTS on the ARN-6 over the PA while working a priority C-130 (gray bird) after a heavy snow at Yokota...an announcement.... "the following offices are closed due to inclement wx ....CBPO (now MPF), Finance, flight line chow hall, etc....." Tromping thru shin high wet snow was so awesome while trying to fix a pressure feed thru coax connector for the marker beacon in the left main wheel well. A heater was no good, only made things wetter! Bob Wow...where was supervision? Home in bed? I'd say that called for demanding hanger time. Troops safety first. Quote Link to comment Share on other sites More sharing options...
tinyclark Posted June 8, 2010 Share Posted June 8, 2010 Put it in a hangar for avionics work? HAH! I started crimping center pins on coax lines on the AWADS RADAR system during one winter at Ramstein, circa 1979. It was so cold in the radome the solder iron wouldn't work. I think I've said on here before that it was always a break to have to work an enroute C141 when all the radar toads in the 435OMS were on leave or whatever. The crew chief usually had the APU running with the heat on. Quote Link to comment Share on other sites More sharing options...
CGRetired Posted June 8, 2010 Share Posted June 8, 2010 In case you REALLY miss it, you can get one of these... Quote Link to comment Share on other sites More sharing options...
INS/Dopplertroop Posted June 9, 2010 Share Posted June 9, 2010 Hahahahaha That's great. That would be quite the conversation piece for the rec room. What are they asking for it? Quote Link to comment Share on other sites More sharing options...
CGRetired Posted June 11, 2010 Share Posted June 11, 2010 Sorry to disappoint. That came out of the bird that lost it's crew door in flight. The repairs required the galley to come out. So.....since you NEVER pass up an oppourtunity for training (and busting on another rate) the sign appeared. Senior sends Quote Link to comment Share on other sites More sharing options...
n1dp Posted June 11, 2010 Share Posted June 11, 2010 Did the RO keep track of cups served in the green Radio Logbook? That is darn funny! Thanks! Quote Link to comment Share on other sites More sharing options...
EClark Posted June 11, 2010 Share Posted June 11, 2010 Did any of you men get with your radio man in the middle of the night in Mildenhall talk to you Mom back in the states mind being Ky. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.