Excellent Dave! Many of us get a headache trying to figure out the nuances of the various radios that we may use. As usual, you always bring the technology to the everyday user in plain language so that we actually can understand what things are all about. Thank you so much.
After watching your videos on the General License with the old intro music I have to say the new intro music is much better. Thanks for all the great videos.
Thanks, Dave. Working with my TH-9800 without a programming cable has been less than enjoyable. It helped to 'pirate' a copy of the Yeasu FT-8900 manual. Using the FTdx 3000 is far more enjoyable but that's HF and a different world. In the meantime, a programming cable is on a slow boat from China. A girlfriend once said 'Patience is a Virtue'. Sam aka KK4VTC or 304X0.
Most of the repeaters here transmit tones, so TSQL works. Further, most drop the tone before dropping the carrier. When it does so, the receiver mutes so the squelch tail when the carrier drops is not heard.
Always very informative. Your videos are always a pleasure to view. Dave can we have a video based on making traps for multi band Dipole antennas. 73's
In DTCS, I would refer to the "polarity" as endianness: en.wikipedia.org/wiki/Endianness . That said, very fine video! Thanks for all your contributions in furthering Ham Radio!
I am new and still learning so I may be wrong. But I think that your example about the repeater offset, beginning around 11:55, has the repeater transmit and receive frequencies reversed. If the repeater is listed as "147.195+" then I think the repeater transmits (and the operator receives) on 147.195; and the repeater receives (and the operator transmits) on 147.795. But again I could be wrong.
No, I agree with you, CJ. The discussion at 3:42 to 4:18 is correct: when I listen to a repeater the numbers on my radio show the frequency I'm listening to, which is the frequency the repeater is transmitting on. The plus sign next to that frequency in a list of repeaters (for example), says the second channel (my transmit, the repeater's receive frequency) for the communication is _above_ the one I dial into my radio.
I have a question for you Dave. What is puzzling me is which type of antenna would be best for me for OTA TV viewing pleasure. My preference is to make either a Gray-Hoverman or a Channel-Master double bay whiskers type ultimate antenna. Would you give me an overview what is going on with both, gain, reception, signal to noise ?? Maybe a video would be great for everyone on UA-cam to be able to know for their TV over the air viewing. Thanks vf
Good video, Dave. I enjoy all of them you do. Did you misspeak at 12:05 talking about the "+" for the repeater frequency? You said the 147.195+ repeater will transmit 600kHz above that at 147.795. Earlier in the video (at 4:01) you said the listed frequency is the frequency you need to listen on, and is the frequency the repeater transmits on.
Aviation still use AM because if two stations send at the same time, both stations can be heard. If they transmitted using FM, both stations would be canceled out.
That’s Simply NOT TRUE...If 2 aircraft end up on the Same Frequency, the Stronger Signal will be “Captured” while the other station will have to wait...it’s called the “Capture Effect”...just thought you’d like to know...
Hi Bill! You're absolutely correct that the capture effect is a real phenomenon and does occur, however it only occurs with FM and PM modes. The capture effect does not occur with AM. You can read more about this at the link Bob provided, or this one: en.m.wikipedia.org/wiki/Capture_effect Just thought you'd like to know!
question... if i have 2 gmrs walkie talkies and i want transmit to the same channel like one will be on channel 7 then the other one is on channel 22 only one can recieve transmit if i put them both on the same channel they dont transmit at all wat am i doing wrong
aircraft use AM tx/rx for air to ground because of the wave pattern is better then FM which is generaly a line of sight flat signal and with an aircraft at say 30.000 ft it's signal would go straight over the ground station/airfield or somthing along those lines ( not trying to condescending either ) 2E0FOK
I'm a pilot and a ham, and though that does not make me an expert on either, I think Dave is much closer to the mark than this. Aviation comms channels are spaced at 25 kHz in the US and 8.33 kHz in Europe. The bandwidth of a typical aviation comms transmitter is on the order of 6-8 kHz, and for the narrower spacing, necessarily closer to the lower end of that. As Dave said in the vid, hams use 30 kHz spacing for FM, and the signals are typically 15 kHz wide. But this is apples and oranges as the FM signals sound better. :-) In any case, aviation could double the number of channels in its band by switching to SSB and would experience no loss in sound quality (though the accuracy of tuning would have to be much better than is typical in the flying museum pieces that most of the aviation fleet is using). I think the "real" answer here has to do with what was feasible in an aviation comms radio at the time the decision to use AM was made. Radios could not be too big, use too much power, or weigh to much. They had to be robust in a high-vibration environment, etc. AM is very forgiving of mistuning, for example, and using 6-8 kHz of a 25 kHz channel allowed you to use simpler/lighter/more robust input filters. Fast forward to today, and it's "easy" to implement just about any modulation, filtering scheme, whatever, using digital technologies, and so the aviation world could modernize to something that would allow more channels and sound better. But there are a lot of radios flying, and aircraft owners hate, hate, HATE being forced to upgrade equipment that "Works Just Fine". Avionics also cost a lot. The typical 40W combined "NAV/COM" radio with flip/flop tuning that was standard for decades is still going to set you back $3000-6000 (www.aircraftspruce.com/categories/pilot_supplies/ps/menus/av/navcom_0browse.html) and that does NOT include installation. Meanwhile, your junky old NARCO soldiers on. Also complicating matters would be the need to have radios that could support the old and new standards simultaneously, as you cannot convert every aircraft and controller station overnight. The radio navaids in use (VORs) are also AM modulated, and can share similar receiver designs to the comms receivers. Actually, the format of a VOR signal is quite interesting and is worth some time if you are interested in such things. The signal contains an AM modulated carrier that contains a morse identifier and often, voice weather information. There is also a 9960 Hz subcarrier in which a 30 Hz signal is FM modulated. The entire signals is "rotated" around the transmitting antenna at 30 Hz (this is done electronically today) at 30 Hz, and the phase difference between the 30 Hz FM signal and the 30 Hz modulation of the overall signal gives you the azimuth to the station. Clever and weird. Did I mention that VORs are being phased out for GPS and other RNAV? Of course they are ... but somehow the FAA is in no rush to decommission too many of its VORs. (en.wikipedia.org/wiki/VHF_omnidirectional_range) In short: it's complicated.
Hi Dave, I have an ICON IC 7000 and have set up a solar panel and two 70Ah deep cycle batteries. The problem is the IC7000 needs 13.5 volts and when the batteries drop down in voltage to 12.5 volts the rig starts to reset. Any ideas how to address the problem.
Hi Dave, I have a question about making a rf choke for my new mosely beam and lightning arrester. ..any info would be great. ..if I need longer coax should I replace or can I use a barrel between 2 pl259...thanks Dave
You should follow the instructions in the Moseley beam manual. Ideally you won't have any breaks in cables, but that's not usually possible, so connecting two cables with a barrel connector is normal.
New Hams, life's too short to be dealing with those Chinese HT radios. Get a Kenwood TH-K20A HT and move on to more important things - like being able to program your HT, without a data cable, after several months without the manual and watching a YT. Being able to program your HT in the field cannot be overstated. Trust me, I am a relatively new Ham and bought the Baofeng HTs and they are fine - if you program them with a cable and the CHIRP software. The TH-K20A is an excellent HT - it charges quickly, and works great with the stock antenna! And don't bother buying a third-party antenna like the Diamond or Nagoya - the stock TH-K20A antenna is shocking good. The Baofeng data cable and mics work great with the TH-K20A - most of the Chinese HTs use "Kenwood" connector! And on the subject of the data cable - spend the extra $$$ and get the Baofeng data cable that uses the FTDI chipset. It will save you more time, and cause less driver frustration under Windows. It's too bad that Kenwood stopped making the TH-F6A or I'd recommend that radio - one HT, three bands 2m/1.25m/70cm.
The only plausible explanation I've heard for AM being kept for Aeronautical VHF: AM has no "capture effect" that FM promoters are quick to point out. If two signals are transmitted on the same frequency, the presence of both of them is more likely to be detected even if one is substantially weaker than the other. If the carriers are very precisely tuned, sidebands from both signals can be heard. If not, the beat frequency-usually a tone-is a giveaway that there's something else under the biggest signal. There are arguments to be made that given the band's use for distress communications and location beacons, it might be good if weak signals aren't buried under the locals.
When two aircraft transmit at the same time on AM, the controller will hear them both. However, if two people transmit on FM, they will be wiped out. The aircraft band doesn't transmit AM by tradition. They do that so no communication is lost.
Robert Shorkey : have you ever used an airband radio? I have several hundred hours as a pilot. When two pilots double on a given frequency everyone hears an annoying squeal and it is very rare that one, much less both signals are intelligible. I suppose a trained ear can do better than mine, but what usually happens is the controller tells the pilot he was stepped on,the and he tries again. That is the reality of airband comms. I didn't say anything about tradition. I said something about history. If you knew anything about aviation, you would know that it is exceedingly difficult to get aircraft operators to re-equip their aircraft. A wholesale changeover to a new transmission mode is a huge political challenge, not a technical one.
+David Jacobowitz _"For one, you don't want to hear weak signals mixed with strong ones for the most part."_ You certainly do if the weak signal is a distress call. _"I'd much prefer a system where you could just hear both transmitters!"_ FM won't help you, then.
Excellent Dave! Many of us get a headache trying to figure out the nuances of the various radios that we may use. As usual, you always bring the technology to the everyday user in plain language so that we actually can understand what things are all about. Thank you so much.
Dave, thanks so much for the clarification. You give great explanations. I really appreciate your videos. Joy
Mr. Casler, the knowledge you provide helped me to expand my professional services, thank you Sir.
Wish I could have watched this back when I just got my license. Thanks for the video.
After watching your videos on the General License with the old intro music I have to say the new intro music is much better. Thanks for all the great videos.
Thank you so much for this.. Going through the columns on Chrip, that's something I found missing from the other videos I watch on how to use Chirp..
New Ham operator here.... THANK YOU SOOOOOO much!!
You're welcome!
I just ordered the MFJ1982 EF, and going to QS radio tomorrow, they are about 20 minutes from me. Thanks for the leads.
Thanks, Dave. Working with my TH-9800 without a programming cable has been less than enjoyable. It helped to 'pirate' a copy of the Yeasu FT-8900 manual. Using the FTdx 3000 is far more enjoyable but that's HF and a different world. In the meantime, a programming cable is on a slow boat from China. A girlfriend once said 'Patience is a Virtue'. Sam aka KK4VTC or 304X0.
Most of the repeaters here transmit tones, so TSQL works. Further, most drop the tone before dropping the carrier. When it does so, the receiver mutes so the squelch tail when the carrier drops is not heard.
Nice job, Dave. Thank you.
Always very informative.
Your videos are always a pleasure to view.
Dave can we have a video based on making traps for multi band Dipole antennas.
73's
I'm hoping to get a trapped antenna from MFJ for analysis and review.
Very good video, especially for the new ham.
Good vid Dave, good info for the newbie
In DTCS, I would refer to the "polarity" as endianness: en.wikipedia.org/wiki/Endianness . That said, very fine video! Thanks for all your contributions in furthering Ham Radio!
Dear Dave thanks a lot for excellent Videos 73!! from YV5IUA
Great information for me, the newbie!
Fantastic!
Great explanation, learning a lot , thanks
Thanks Dave. Great stuff as usual.
Thank you!
aircraft does use SSB but only on HF. I monitor HF here.
great video
Thank you!!!
You're welcome!
I am new and still learning so I may be wrong. But I think that your example about the repeater offset, beginning around 11:55, has the repeater transmit and receive frequencies reversed. If the repeater is listed as "147.195+" then I think the repeater transmits (and the operator receives) on 147.195; and the repeater receives (and the operator transmits) on 147.795. But again I could be wrong.
If I'm wrong, can someone please correct me. Did I totally misunderstand the discussion from 3:42 - 4:18?
No, I agree with you, CJ. The discussion at 3:42 to 4:18 is correct: when I listen to a repeater the numbers on my radio show the frequency I'm listening to, which is the frequency the repeater is transmitting on. The plus sign next to that frequency in a list of repeaters (for example), says the second channel (my transmit, the repeater's receive frequency) for the communication is _above_ the one I dial into my radio.
Donald Miller, thanks! I was beginning to wonder if I had misunderstood.
Yep, I got it backwards.
I have a question for you Dave. What is puzzling me is which type of antenna would be best for me for OTA TV viewing pleasure. My preference is to make either a Gray-Hoverman or a Channel-Master double bay whiskers type ultimate antenna. Would you give me an overview what is going on with both, gain, reception, signal to noise ?? Maybe a video would be great for everyone on UA-cam to be able to know for their TV over the air viewing. Thanks vf
Can someone please tell me what the tune is at the beginning of Dave's videos. Been driving me nuts knowing I've heard it before
Good video, Dave. I enjoy all of them you do.
Did you misspeak at 12:05 talking about the "+" for
the repeater frequency? You said the 147.195+ repeater will transmit
600kHz above that at 147.795. Earlier in the video (at 4:01) you said the listed
frequency is the frequency you need to listen on, and is the
frequency the repeater transmits on.
Oops, looks like I got that backwards. The user's handheld transmits 600 kHz above. Good catch!
Aviation still use AM because if two stations send at the same time, both stations can be heard. If they transmitted using FM, both stations would be canceled out.
More to support my answer. en.wikipedia.org/wiki/Airband
Good point.
That’s Simply NOT TRUE...If 2 aircraft end up on the Same Frequency, the Stronger Signal will be “Captured” while the other station will have to wait...it’s called the “Capture Effect”...just thought you’d like to know...
Hi Bill! You're absolutely correct that the capture effect is a real phenomenon and does occur, however it only occurs with FM and PM modes. The capture effect does not occur with AM. You can read more about this at the link Bob provided, or this one: en.m.wikipedia.org/wiki/Capture_effect
Just thought you'd like to know!
question... if i have 2 gmrs walkie talkies and i want transmit to the same channel like one will be on channel 7 then the other one is on channel 22 only one can recieve transmit if i put them both on the same channel they dont transmit at all wat am i doing wrong
aircraft use AM tx/rx for air to ground because of the wave pattern is better then FM which is generaly a line of sight flat signal and with an aircraft at say 30.000 ft it's signal would go straight over the ground station/airfield or somthing along those lines ( not trying to condescending either ) 2E0FOK
Radio propagation is actually pretty much mode-agnostic, and AM and FM signals using the same antennas will propagate across the same path.
aha just been speaking with an aviation historian and its to do with signal band width you can get more on am than fm apparently
I'm a pilot and a ham, and though that does not make me an expert on either, I think Dave is much closer to the mark than this. Aviation comms channels are spaced at 25 kHz in the US and 8.33 kHz in Europe. The bandwidth of a typical aviation comms transmitter is on the order of 6-8 kHz, and for the narrower spacing, necessarily closer to the lower end of that. As Dave said in the vid, hams use 30 kHz spacing for FM, and the signals are typically 15 kHz wide.
But this is apples and oranges as the FM signals sound better. :-) In any case, aviation could double the number of channels in its band by switching to SSB and would experience no loss in sound quality (though the accuracy of tuning would have to be much better than is typical in the flying museum pieces that most of the aviation fleet is using).
I think the "real" answer here has to do with what was feasible in an aviation comms radio at the time the decision to use AM was made. Radios could not be too big, use too much power, or weigh to much. They had to be robust in a high-vibration environment, etc. AM is very forgiving of mistuning, for example, and using 6-8 kHz of a 25 kHz channel allowed you to use simpler/lighter/more robust input filters.
Fast forward to today, and it's "easy" to implement just about any modulation, filtering scheme, whatever, using digital technologies, and so the aviation world could modernize to something that would allow more channels and sound better. But there are a lot of radios flying, and aircraft owners hate, hate, HATE being forced to upgrade equipment that "Works Just Fine". Avionics also cost a lot. The typical 40W combined "NAV/COM" radio with flip/flop tuning that was standard for decades is still going to set you back $3000-6000 (www.aircraftspruce.com/categories/pilot_supplies/ps/menus/av/navcom_0browse.html) and that does NOT include installation. Meanwhile, your junky old NARCO soldiers on. Also complicating matters would be the need to have radios that could support the old and new standards simultaneously, as you cannot convert every aircraft and controller station overnight.
The radio navaids in use (VORs) are also AM modulated, and can share similar receiver designs to the comms receivers. Actually, the format of a VOR signal is quite interesting and is worth some time if you are interested in such things. The signal contains an AM modulated carrier that contains a morse identifier and often, voice weather information. There is also a 9960 Hz subcarrier in which a 30 Hz signal is FM modulated. The entire signals is "rotated" around the transmitting antenna at 30 Hz (this is done electronically today) at 30 Hz, and the phase difference between the 30 Hz FM signal and the 30 Hz modulation of the overall signal gives you the azimuth to the station. Clever and weird. Did I mention that VORs are being phased out for GPS and other RNAV? Of course they are ... but somehow the FAA is in no rush to decommission too many of its VORs. (en.wikipedia.org/wiki/VHF_omnidirectional_range)
In short: it's complicated.
Hi Dave,
I have an ICON IC 7000 and have set up a solar panel and two 70Ah deep cycle batteries. The problem is the IC7000 needs 13.5 volts and when the batteries drop down in voltage to 12.5 volts the rig starts to reset. Any ideas how to address the problem.
Yes. Here's what I use: stores.tgelectronics.org/the-new-n8xjk-boost-regulator/. MFJ has something similar.
Hi Dave, I have a question about making a rf choke for my new mosely beam and lightning arrester. ..any info would be great. ..if I need longer coax should I replace or can I use a barrel between 2 pl259...thanks Dave
You should follow the instructions in the Moseley beam manual. Ideally you won't have any breaks in cables, but that's not usually possible, so connecting two cables with a barrel connector is normal.
thanks for all the great videos~ very informative as always.
73s!
4G1KMT
New Hams, life's too short to be dealing with those Chinese HT radios. Get a Kenwood TH-K20A HT and move on to more important things - like being able to program your HT, without a data cable, after several months without the manual and watching a YT. Being able to program your HT in the field cannot be overstated.
Trust me, I am a relatively new Ham and bought the Baofeng HTs and they are fine - if you program them with a cable and the CHIRP software. The TH-K20A is an excellent HT - it charges quickly, and works great with the stock antenna! And don't bother buying a third-party antenna like the Diamond or Nagoya - the stock TH-K20A antenna is shocking good.
The Baofeng data cable and mics work great with the TH-K20A - most of the Chinese HTs use "Kenwood" connector! And on the subject of the data cable - spend the extra $$$ and get the Baofeng data cable that uses the FTDI chipset. It will save you more time, and cause less driver frustration under Windows.
It's too bad that Kenwood stopped making the TH-F6A or I'd recommend that radio - one HT, three bands 2m/1.25m/70cm.
So how do i donate $$ to this radio advancing channel.
Am ve3myr in Canada...exchange rate?
Do i just send u ten bucks American in the int'l mail ?
The only plausible explanation I've heard for AM being kept for Aeronautical VHF: AM has no "capture effect" that FM promoters are quick to point out. If two signals are transmitted on the same frequency, the presence of both of them is more likely to be detected even if one is substantially weaker than the other. If the carriers are very precisely tuned, sidebands from both signals can be heard. If not, the beat frequency-usually a tone-is a giveaway that there's something else under the biggest signal.
There are arguments to be made that given the band's use for distress communications and location beacons, it might be good if weak signals aren't buried under the locals.
Good points all.
When two aircraft transmit at the same time on AM, the controller will hear them both. However, if two people transmit on FM, they will be wiped out. The aircraft band doesn't transmit AM by tradition. They do that so no communication is lost.
Robert Shorkey : have you ever used an airband radio? I have several hundred hours as a pilot. When two pilots double on a given frequency everyone hears an annoying squeal and it is very rare that one, much less both signals are intelligible. I suppose a trained ear can do better than mine, but what usually happens is the controller tells the pilot he was stepped on,the and he tries again. That is the reality of airband comms.
I didn't say anything about tradition. I said something about history. If you knew anything about aviation, you would know that it is exceedingly difficult to get aircraft operators to re-equip their aircraft. A wholesale changeover to a new transmission mode is a huge political challenge, not a technical one.
+David Jacobowitz _"For one, you don't want to hear weak signals mixed with strong ones for the most part."_
You certainly do if the weak signal is a distress call.
_"I'd much prefer a system where you could just hear both transmitters!"_
FM won't help you, then.