don't forget to file for renewal with the FCC. 10 years goes by fast!
Communications Plan
- Thread starter Captjim_NM
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May as well scrap the licencing system over here, all I ever hear is only old guys doing radio checks ans Russian taxi drivers with 200 watt burners . Satelite phones are gaining in popularity in some quarters.
Frequency hopping does not come without challenges ~ and it is more of a means to prevent eavesdropping than a means to conceal location. The days of the Realistic police scanner are gone. With moderately capable test equipment becoming cheap enough for the radio enthusiast, if you transmit, you can be found. And with frequency hopping, the frequencies are not in the same band so now you will need multi-band antennas with the same radiation pattern on all bands.
Anyone with a spectrum analyzer can drive around and find where the signals get stronger, even if they are not tuned into and listening to any of them. In fact, I was just watching the signals from my phone pop up on the spectrum as I was texting a friend yesterday. Yagi's are ok for VHF and UHF foxhunts but I think doppler shift and TDOA interferometer techniques are easier for VHF frequencies. Adcock arrays's and variable phase antenna arrays (like using a radio goniometer), are great for HF. The null of a bar antenna or loop antenna is very sharp, just like the adcock, sharper than the main lobe by far. Same applies to many antennas so by using a balanced loop antenna etc, you can get a very accurate direction using the null (when the signal disappears) in the patters as opposed to the 50° to 60° 3dB directivity of a 5 or 6 element yagi.
Using VHF and UHF for local comms is ideal since those signals won't go far. NVIS is great for lower frequency HF work because it goes up and comes back down meaning that instead of a dipole at a half wavelength above ground that illuminates two directions and travels (for the most part) along the ground hitting the ionosphere 800 miles away before refracting back down, NVIS antennas near good ground (10-20 feet) illuminates a 600 mile radius with no dead zones. Locating a signal that comes from above is much harder because less people are going to try to find the angle of incidence and make predictions about the amount of ionospheric refraction and ducting to guess where you are.
Use only enough power on a band that has just sufficient propagation to get the message sent.
Anyone with a spectrum analyzer can drive around and find where the signals get stronger, even if they are not tuned into and listening to any of them. In fact, I was just watching the signals from my phone pop up on the spectrum as I was texting a friend yesterday. Yagi's are ok for VHF and UHF foxhunts but I think doppler shift and TDOA interferometer techniques are easier for VHF frequencies. Adcock arrays's and variable phase antenna arrays (like using a radio goniometer), are great for HF. The null of a bar antenna or loop antenna is very sharp, just like the adcock, sharper than the main lobe by far. Same applies to many antennas so by using a balanced loop antenna etc, you can get a very accurate direction using the null (when the signal disappears) in the patters as opposed to the 50° to 60° 3dB directivity of a 5 or 6 element yagi.
Using VHF and UHF for local comms is ideal since those signals won't go far. NVIS is great for lower frequency HF work because it goes up and comes back down meaning that instead of a dipole at a half wavelength above ground that illuminates two directions and travels (for the most part) along the ground hitting the ionosphere 800 miles away before refracting back down, NVIS antennas near good ground (10-20 feet) illuminates a 600 mile radius with no dead zones. Locating a signal that comes from above is much harder because less people are going to try to find the angle of incidence and make predictions about the amount of ionospheric refraction and ducting to guess where you are.
Use only enough power on a band that has just sufficient propagation to get the message sent.
Amish Heart
A True Doomsday Prepper
Good info
firewallsrus
Member
If you think there is a possibility of being obscure while communicating online then I don't know how to begin to explain how open people are. I don't know what part of the world you are in, but the fact that you are online means you are very trackable. I spent 30 years in data communications security.
HT radios can't be "tweaked" to put out more power and if they did there would be little point as going from the "out of the box" 5 Watts up to 8 Watts wouldn't even show up on an S meter. There are children (with entry-level licenses) using 5 Watt HT's to communicate with astronauts on the International Space Station. Whatever nation you are in, there are authorities who can pin down your location within less than a second if they want to find you.
As for OPSEC? There are a lot of ways of ensuring OPSEC and they are ALL relative. Every modern warfare unit uses communications which can be pinpointed using direction finding gear. I do agree that you would not set up and operate a base station in my home. I however would for many reasons you probably cannot imagine.
Other than plug and play handi talkies, someone without a license and practice would be very unlikely to be able to get a useable signal out for reasons spelled out in detail elsewhere.
The FCC has my PO Box in the next town for an address. I do not have a physical mailbox here.
firewallsrus
Member
I toss this article about ham radio for the prepper as an invitation to discussion. Folks that don't want to ever use a radio are not really the target audience, but I will do my best to answer any questions and will edit the article as needed. Introduction to ham radio
Amish Heart
A True Doomsday Prepper
Good info, firewallsrus
firewallsrus
Member
Thank you, but my knowledge is limited and I would love to see others throwing ideas up.
Amish Heart
A True Doomsday Prepper
I'm only a tech. You're doing fine.
EricB1970
Active Member
For local comms up to 500-600 miles I prefer NVIS on 40m and 80m. VHF and UHF for patrolling small areas, say up to 5 miles. Daily rolling frequencies are a good idea, as well as using duplex. Switching the duplex during daily use also adds to confusion. If things are getting hot, switching frequencies more often, say every hour will also help. There's plenty of ways to keep the enemy confused. Always use code words and phrases and no one will know what the hell you're talking about.
OPSEC with a licence is easy, just use a PO box, problem solved.
OPSEC with a licence is easy, just use a PO box, problem solved.
Opsec is vital AFTER TSHTF but not an issue in normal times, I know my ISP etc can be traced, but TS has not yet HTF so I'm not overly concerned. BUT when the balloon goes up OPSEC is paramount. After TSHTF Radio stations in fixed locations are easy to triangulate, so having an operational ham base at your retreat or BOL is simply inviting trouble. They find your radio they find your supplies. I like Ham gear but again after TSHTF your address is easily available in libraries, council offices etc from the Ham register, thats why I wont get a licence.
But in all fairness to the ham community I also do not broadcast on Ham bands mainly out of respect, though I do listen.
I've managed to achieve short range comms using the UV5s on the PMR 446 channels, which meets my local needs. I've got a 40 watt Pres Grant 2 Export model AM/FM/ SSB CB Ham unit for greater reach to the families vehicles, its hardly ever turned on because of Russian and Polish idiots blasting out noise.
UK market PMR (FRS) radios are limited by law to .5 watt, we get round it by using UV5 Rs on the same 440 frequencies but using 5 or 8 watts through nagoya 771s , they more than meet our local needs. Naturally in the US ranges and distance are huge and require a different approach. We are also trying out ABBREE ants with improving results over the 771s.
I like this thread.
Interest in HAM radio is picking up around here too, Im president of our radio club and we have a list waiting to take their radio tests for a lisc, We currently have 183 members and lots of them are involved with emergency prepardness on statewide basis, last night from our club we were talking to scotland, south america and japan!!! ITS a VERY interesting hobby and can be a great help when SHTF!!!!
I doubt anyone will have their station located by enemy forces. Identify the working conditions and classify your threats... A government, they won't need your food and won't RDF you unless you have directly kicked their hornets nest (not saying kicking it is a bad thing). An educated, well-prepared person that actually has the knowledge and experience to fabricate a means of timely direction finding is likely doing fine without your stuff. A group of insurgents, mostly acting to enter pulic eye and will be unlikely to take their chaos into residential zones. A super-smart criminal that never applied himself, this guy might be an issue, but with the vast number of radio stations coming online when SHTF (some unlicensed radio enthusiasts with bad equipment, not to mention all the legit stations now handling 10x their normal message load), his RDF skills will need to be honed as now you need to use your ears along with that dB signal bar. I think that guy will just use his eyes to find what he needs.
I agree with firewallsrus on the power thing. Its roughly 3dB every time one doubles or halfs the power. Going from 5w to 8w is not even getting you 3 dB, which when one S-unit on the receiver is 6dB, you are just stressing your final amplifier having it cranked up for something that wont help a line-of-sight radio much. The magic is in the antenna and feed line. VHF and UHF can do some cool stuff. Unlike HF that depends on the ionosphere and solar conditions, VHF and higher experiences enhanced propagation primarily by means of the troposphere and is influenced by weather. If you have a yagi, aim your signal along the back edge of a cold front once or aim it along a coastline just after sunset
You might talk 1000 miles. I hit an Ohio repeater on the coast of Lake Erie from Minnesota with my HT by accident once. I think a temperature inversion set up over Superior, Michigan and Erie that day.
There is a fun part of radio which does makes it valuable post SHTF with respect to morale and sanity (i go to town once a month in the winter). Anyone can shoot some 1200 mile skip on a CB, but when those unusual modes propagation shine, so does my hillbilly toothless smile! We had auroral propagation a while back that lasted forever and us 5 locals suddenly heard a group of 3 canadian locals talking (all 3 on a lake about 350-400 miles from here ~ a difficult distance for CB) and us 8 spent the whole night passing the mic around. The interesting part was that it remained stable for hours and it was just our two locations. Usually auroral propagation moves around. The chaos of normal F2 daytime to the south cant even begin to compare with how awesome that evening of auroral propagation was! Then you get into the books and learn about all the other neat ways signals can propagate and next thing you know you have your house buried in countless antennas
I agree with firewallsrus on the power thing. Its roughly 3dB every time one doubles or halfs the power. Going from 5w to 8w is not even getting you 3 dB, which when one S-unit on the receiver is 6dB, you are just stressing your final amplifier having it cranked up for something that wont help a line-of-sight radio much. The magic is in the antenna and feed line. VHF and UHF can do some cool stuff. Unlike HF that depends on the ionosphere and solar conditions, VHF and higher experiences enhanced propagation primarily by means of the troposphere and is influenced by weather. If you have a yagi, aim your signal along the back edge of a cold front once or aim it along a coastline just after sunset
You might talk 1000 miles. I hit an Ohio repeater on the coast of Lake Erie from Minnesota with my HT by accident once. I think a temperature inversion set up over Superior, Michigan and Erie that day.There is a fun part of radio which does makes it valuable post SHTF with respect to morale and sanity (i go to town once a month in the winter). Anyone can shoot some 1200 mile skip on a CB, but when those unusual modes propagation shine, so does my hillbilly toothless smile! We had auroral propagation a while back that lasted forever and us 5 locals suddenly heard a group of 3 canadian locals talking (all 3 on a lake about 350-400 miles from here ~ a difficult distance for CB) and us 8 spent the whole night passing the mic around. The interesting part was that it remained stable for hours and it was just our two locations. Usually auroral propagation moves around. The chaos of normal F2 daytime to the south cant even begin to compare with how awesome that evening of auroral propagation was! Then you get into the books and learn about all the other neat ways signals can propagate and next thing you know you have your house buried in countless antennas
just a thought, but wont it be a real pickle if all the two way radios we have bought made in China, Japan, Tiawan and Korea have kill switches built in?? I'm told many circuit boards and chip sets for radios produced OUTSIDE China are made with boards and chips made IN China.
A guy from another forum said the same thing a while back. He was a self-proclaimed "electrical engineer" and had absolutely zero evidence to prove his claim. With youtube channels like The Signal Path and other REAL electrical engineers doing teardowns of various products, I highly doubt it. Why would the Chinese want to turn off your ability to communicate a few miles? You using them if they invaded would be to their benefit anyhow.
True I was just thinking aloud after many government have banned Chinese companies from getting 5G telecoms contracts because they believe they are vulnerable to hacking. Many fear they could hack and close down or hack and steal data if their technology was allowed to be used.
If the much brighter than me governments and Sigint experts fear that level of intrusion I just wondered if they could design an offswitch into the systems of their Ham gear??
Captjim_NM
Active Member
Hacking can be a software issue, as such can be solved with software refinements. MNwe786 has a VERY STRONG point about propagation of a 5 watt vs 8 watt VHF radio. Remember people, we are talking about a handheld battery powered device. More power eats up your battery time. If you had enough land were this would be a problem, then set-up observation posts and have a stealth antenna hoisted up into a tree. When the observer arrives at the opservation post, just connect his HT to the tree mounted antenna. With the antenna 20 to 30 feet up in the tree he would more than double his communication range, much more effective than increasing power and eating more battery. de KA5SIW
Slot antennas!!!
Very true! Here's a fun calculator for that
https://www.easycalculation.com/physics/electromagnetism/line-of-sight.php
And to further the topic, lets talk coax cable. All coax has loss that increases with frequency, its specified the datasheet of every coax. At VHF and UHF, these losses are significant (and work in both directions). Lets quickly compare just two very common 50ohm coax cables to illustrate the issue...
RG-8X has a loss of 4.3dB/100ft at 150MHz and 7.5dB/100ft at 450MHz (as opposed to the tolerable 1.94dB/100ft @ 30MHz). LMR-400 has a loss of 1.5dB/100ft loss at 150MHz and 2.7dB/100ft at 450MHz.
In other words, if you are running FRS frequencies through 30ft of RG-8X coax (assuming a perfect impedance match at the antenna, 1:1 SWR), almost half of your transmitter power is used warming up the coax (every 3dB change represents roughly 50% of the power remaining so 100w sees 3dB loss, now its 50w. that 50w sees 3dB more, now its 25w and so on). I recommend for base stations to buy some LMR-400 or Heliax LDF4-50 (and don't bend the heliax too many times
for a very cool .85dB and 1.51dB loss/100ft respectively).EDIT: It's easy to stop by radio shack and grab some of their truck stop coax, but that junk is single shield with horrible braid coverage. Don't use that stuff on UHF. Its funny that the CB and HF ham antenna jacks (the SO-239 connectors) are called "UHF" connectors when they SUCK at UHF lol. And those SO-239 (UHF female) to SMA adapters online for 2 bucks used to connect your handhelds to an external antenna... get off ebay or amazon and go buy a real 50ohm connector from a reputable source like RFParts. If it isn't at least $20, its probably a junk connector thats not 50ohm due to the low-melting mystery plastic they use as an insulator. Here I go, If its radio, i never know where to stop lol
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Thats why i LOVE field days, learning to operate from mobile positions with limited or alternative power supplies!!!
