Guess I upset somebody on a forum...
Most of the experiences with people I've met of the forums have been positive, but occasionally you get one that doesn't like criticism, especially from a female...The worst example was an elderly gent from the USA who really should know better. He claims to be a licensed "radio ham" and says he has been since 1977.
There was a debate on the forum about a modulation hack called the "npc/rc modification" which is usually accompanied by butchering (deliberately disabling) limiters present in the radio that are designed to prevent clipping and to keep the modulation index to less than 1.
These modifications certainly increase the "loudness" of a transmitted signal, but at a cost. The "npc/rc" works by allowing the modulation index to go well above 1, sometimes to 3 or 4, and uses a diode to prevent cutting the carrier off. Any sensible RF engineer will be cringing severely at this point - the baseband is cut off in the negative going direction only, generating plenty of in-band (baseband signal) harmonics. The very high modulation index then gives them the means to leave via the modulator and subsequently the antenna. Some users also employ extremal power amplifiers, sometimes with an output of over 1KW (or so they think / claim!).
The result sounds very loud, but so distorted it's unusable: For you listening (dis)pleasure, have a listen here.
A much bigger concern is what happens to all of that RF they are radiating. As any RF engineer knows, the above scenario will be radiating up to 90% of it's signal on frequencies other that the one they have selected - their "1000 watts" consists of 100W of on-channel energy and 900 watts of spurious (unwanted signal that can interfere with other users and does nothing for their communication efforts). These guys worship their power meters and oscilloscopes, and either don't know or choose to ignore (for financial reasons?) that neither of these two pieces of test equipment cannot tell the difference between wanted signal and spurious - they simply show all of the RF energy present, wanted or not.
I pointed out on a forum that these "hack" modifications are rather inconsiderate to other users on the band. Even posted a few spectrum analyzer screenshots to show that their baseband increase was mediocre to minimal, and that they were increasing two things - their power meter reading and their distortion.
The replies were far from what was expected. PM (private message) pleas to NOT point out the information I posted to start with. Hack mods were a good source of income for a few people, and they said they needed to put food on the table for their families. One user sent me a link to a rather depressing documentary video, made just months before, showing people begging in the streets and rows of abandoned / decrepit housing, and huge queues for basic employment such as fast food joint "crew" and supermarket shelf stackers. This was a huge eye opener for me, after seeing locally "rental auctions" (where the landlord agrees to rent a house to the person who offers the highest rent) and having to offer $35+ per hour with 4 weeks paid vacation per year just to get people to apply for a job on offer at our family business. We eventually got a taker, but it took months. The contrast between conditions here and in the USA was enormous.
Within a few days, it got worse, with subjects / threads being deleted as soon as the realities about these hack mods started to get out. I backed off a little bit by continuing our online chats in private messages. Things quietened down again. Except for two users, the main one being our "I've been a licensed radio ham since 1977" man.
It started out with racist messages, clearly designed to offend, being sent to our Yahoo webmail contact address on the forum:
The first one was a "joke" about why African-Americans don't use ham radio (image below). Charming.
I don't know why blacks though, maybe he thought I was of African-American descent. Eventually he worked out I'm not black but Vietnamese (a last name of Nguyen is a bit of giveaway here!) He then changed his focus from blacks to Asians (another image below):
At this point things started to get a bit creepy. Another message was received, with a picture of a long brass bullet attached. At this point I got our IT guru to block him from our webmail and network, and another forum user showed me how easy it was to "hide" him from our private messages. No more Mr. Creepy... but it didn't last long. He joined up to the AVRF forum and tried the same there, but a forwarding of his earlier emails to the moderator got his AVRF account deleted and his IP address blocked from rejoining. I never heard from him again.
Two of the emails shown below (Warning: Extremely offensive racist material If easily offended, do NOT read further!)
There was a debate on the forum about a modulation hack called the "npc/rc modification" which is usually accompanied by butchering (deliberately disabling) limiters present in the radio that are designed to prevent clipping and to keep the modulation index to less than 1.
These modifications certainly increase the "loudness" of a transmitted signal, but at a cost. The "npc/rc" works by allowing the modulation index to go well above 1, sometimes to 3 or 4, and uses a diode to prevent cutting the carrier off. Any sensible RF engineer will be cringing severely at this point - the baseband is cut off in the negative going direction only, generating plenty of in-band (baseband signal) harmonics. The very high modulation index then gives them the means to leave via the modulator and subsequently the antenna. Some users also employ extremal power amplifiers, sometimes with an output of over 1KW (or so they think / claim!).
The result sounds very loud, but so distorted it's unusable: For you listening (dis)pleasure, have a listen here.
A much bigger concern is what happens to all of that RF they are radiating. As any RF engineer knows, the above scenario will be radiating up to 90% of it's signal on frequencies other that the one they have selected - their "1000 watts" consists of 100W of on-channel energy and 900 watts of spurious (unwanted signal that can interfere with other users and does nothing for their communication efforts). These guys worship their power meters and oscilloscopes, and either don't know or choose to ignore (for financial reasons?) that neither of these two pieces of test equipment cannot tell the difference between wanted signal and spurious - they simply show all of the RF energy present, wanted or not.
I pointed out on a forum that these "hack" modifications are rather inconsiderate to other users on the band. Even posted a few spectrum analyzer screenshots to show that their baseband increase was mediocre to minimal, and that they were increasing two things - their power meter reading and their distortion.
The replies were far from what was expected. PM (private message) pleas to NOT point out the information I posted to start with. Hack mods were a good source of income for a few people, and they said they needed to put food on the table for their families. One user sent me a link to a rather depressing documentary video, made just months before, showing people begging in the streets and rows of abandoned / decrepit housing, and huge queues for basic employment such as fast food joint "crew" and supermarket shelf stackers. This was a huge eye opener for me, after seeing locally "rental auctions" (where the landlord agrees to rent a house to the person who offers the highest rent) and having to offer $35+ per hour with 4 weeks paid vacation per year just to get people to apply for a job on offer at our family business. We eventually got a taker, but it took months. The contrast between conditions here and in the USA was enormous.
Within a few days, it got worse, with subjects / threads being deleted as soon as the realities about these hack mods started to get out. I backed off a little bit by continuing our online chats in private messages. Things quietened down again. Except for two users, the main one being our "I've been a licensed radio ham since 1977" man.
It started out with racist messages, clearly designed to offend, being sent to our Yahoo webmail contact address on the forum:
The first one was a "joke" about why African-Americans don't use ham radio (image below). Charming.
I don't know why blacks though, maybe he thought I was of African-American descent. Eventually he worked out I'm not black but Vietnamese (a last name of Nguyen is a bit of giveaway here!) He then changed his focus from blacks to Asians (another image below):
At this point things started to get a bit creepy. Another message was received, with a picture of a long brass bullet attached. At this point I got our IT guru to block him from our webmail and network, and another forum user showed me how easy it was to "hide" him from our private messages. No more Mr. Creepy... but it didn't last long. He joined up to the AVRF forum and tried the same there, but a forwarding of his earlier emails to the moderator got his AVRF account deleted and his IP address blocked from rejoining. I never heard from him again.
Two of the emails shown below (Warning: Extremely offensive racist material If easily offended, do NOT read further!)