1
Amateur Radio / HAMS on 3927 lsb talking about hfunderpants
« on: November 22, 2023, 0323 UTC »
Lol welcome HAMs checking out hfunderpants and extolling its virtues, there is much to explore at hfhouseplants!
Shortwave Pirate Radio In North America And Around The World, And Other Signals That Go Bump In The Night
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2
Utility / KPH 12585.6 BFSK 50/170 Baudot
« on: March 12, 2023, 2008 UTC »
KPH 12585.6 BFSK 50/170 Baudot 2130Z 11MAR23
Weather warnings and other items of interest to mariners.
Their sheet says they tx on 12585.5 but I got them on 12585.6
Weak but the formed filter in the 756 Pro brought it up to clean decode level.
No hard copy as the Icom doesn't provide for that.
Here's their sched;
https://www.radiomarine.org/mrhs-operations
Weather warnings and other items of interest to mariners.
Their sheet says they tx on 12585.5 but I got them on 12585.6
Weak but the formed filter in the 756 Pro brought it up to clean decode level.
No hard copy as the Icom doesn't provide for that.
Here's their sched;
https://www.radiomarine.org/mrhs-operations
3
Shortwave Broadcast / 12050 WEWN 1859Z 24DEC22
« on: December 24, 2022, 1904 UTC »
Om/yl Sp block Xmas music halleluja, 100kw via Birmingham Al metro area, s9 +10 short flutter fade
4
Shortwave Broadcast / 13820 R Marti 1850Z 24DEC22
« on: December 24, 2022, 1853 UTC »
Om in discussion with yl via fone, 250kw via Edward R Murrow Transmitting Station of the International Broadcasting Bureau, VOA Site B, Greenville, NC
S9 +20, strongest sig on band // with 11860 & 11930 @s7/8
S9 +20, strongest sig on band // with 11860 & 11930 @s7/8
5
Shortwave Broadcast / 13700 RHC (presumed) 1845Z 24DEC22
« on: December 24, 2022, 1849 UTC »
Om in SP presumed running yanqui dogs xmas bcast, 100kw from Bauta Cuba not scheduled or // with 13740
6
Shortwave Broadcast / 13670 World Christian Broadcast 1840Z 24DEC22
« on: December 24, 2022, 1843 UTC »
2 om in EE discussion regarding risks of diseases common to missionary work, 100kw from Mahajanga Madagascar, 10 over s9, stable
7
Shortwave Broadcast / VoA 15580 AM 1830Z 24DEC22
« on: December 24, 2022, 1837 UTC »
2 om in EE discussion re inflation in Liberia and elsewhere, 100kw from Selebi-phikwe, Botswana, s3/5 with slow rolling fade
8
General Radio Discussion / HAARP To Bounce Signal Off Asteroid 2010 XC15 In NASA Experiment
« on: December 23, 2022, 2224 UTC »
HAARP will transmit a continually chirping signal to asteroid 2010 XC15 at slightly above and below 9.6 megahertz (9.6 million times per second). The chirp will repeat at two-second intervals. Distance will be a challenge, Haynes said, because the asteroid will be twice as far from Earth as the moon is.
https://spaceref.com/newspace-and-tech/haarp-to-bounce-signal-off-asteroid-2010-xc15-in-nasa-experiment/#:~:text=An%20experiment%20to%20bounce%20a,satellites%20that%20orbit%20our%20planet.
https://spaceref.com/newspace-and-tech/haarp-to-bounce-signal-off-asteroid-2010-xc15-in-nasa-experiment/#:~:text=An%20experiment%20to%20bounce%20a,satellites%20that%20orbit%20our%20planet.
9
Amateur Radio / Project IC-R71A
« on: December 15, 2022, 0129 UTC »
Whilst perusing qth (for parts for yet another project) I ran across an ad for The Ham Station, and I had to take a look. Dan's linked url displayed his wares and I noted something dear to my heart, namely an Icom IC-R71A for sale, and for sale cheap! I called to see if he still had it, he did and mentioned some details, it was clean but had a few issues. I made arrangements to meet and purchase, we met behind his old building in Evansville as if he was my pusher and me a radio junkie needing a fix. I mean who would turn down an Icom IC-R71A for a lousy $135?
So I get it home and fired up, immediately noting it seemed to have a narrow cw filter installed (yay!) and the bespoke issues. The volume/rf gain knob is fooched so the volume pot has no rotation stop, and the pbt knob was a bit bent, I surmise both were victims to shipping via one of the "drop it or you're fired" companies.
I've been a fan of these rigs since dirt was new, had like 10 of them over the years, and often wondered if I'd ever get rid of the surplus of parts to mod them with, to include a rom board with programming to go from 10kc to 32mc plus a newer battery, stock they tune 100kc to 30mc. The issue here is many Icoms of the era need a good cmos battery or the radio literally forgets how to run if the battery dies before replacement.
Icom stopped building these things a few decades ago and some of them are from the mid 80s so if the cmos battery is original, well, you have been warned. So I opened the rig up to install the rom board and see if it had a cw filter, sure enough an optional Icom cw filter (worth about $50) was in place and the innards were very clean to boot.
Something I almost always do with a new rig is check to see if the various screws are snug, and this time the chassis was fine but each and every pcb was just a bit over finger tight. I wondered how that works if it was like that all the way from Hirano-ku, Osaka, 547-0003, Japan, but I tightened them up and it seemed to quiet down some odd but brief pll/vco/cpu noise it had at first startup that has yet to reappear.
The addition of the new rom board went fine and the initial startup after brain surgery showed it worked fine too, still had the same memories it had when I put the board into a static proof bag years ago. Now this baby tunes all the way down to about 9.4kc in cw mode. Copied wwvb (60kc) last nite with about 10ft of wire fed into a Grove TUN3 (if you remember those) and am fairly impressed with the rig, shamefully lacking a fish finder unlike most of my other rigs.
So this one is going to get the knobs sorted, a fresh alignment, and various mods, some of wich still have parts for.
One of the mods is to replace the pn rf bandpass switching diodes with pin types; the illustrious MI204 PIN diode, bought a mess of them from Icom years ago. These diodes have a much longer carrier lifetime than standard pn diodes, if the rf passing thru the diode isn't high enough frequency, the diode can contribute to imd.
See here for some empirical data on diode caused imd;
https://www.radioamatore.info/attachments/508_TS-940%20-%20PROMOTIONAL%20BROCHURE.pdf
Above say 11mc the as-installed diodes work great, below they start to contribute imd to a slight degree. Replacing the bandpass diodes for all ranges below 11mc will improve performance but not to a startling degree. More or less I just want to use the parts for what I bought them for.
Below 3mc, Icom used the MI204 diodes so they don't have to be replaced, just 3mc to 11mc bandpasses.
The next mod will be a better IF filter for am mode, better as in there is none as stock. The Icom R70 had enough slots for filters for most every mode, the 71 gives you two optional slots, one in the 9mc IF strip and the other in the 455kc strip. The filter I propose here will be around 6kc wide and as it's a monolithic filter, looking like a large canned crystal, will be soldered in the 9mc strip, replacing a cap. I do have a proper Icom 9mc 6kc wide xtal filter but I don't wanna have mini coax going all over, wich that would necessitate.
Then the neat mod, an infinite impedance detector in place of the simple diode detector as present. A good diode detector is fine but a infinite z detectors finer.
See here for more;
http://www.pan-tex.net/usr/r/receivers/elrpicamdetect.htm
Another mod is the nb diodes, the 71 has much better nb action than my other project, Project IC756, and that should not be, yet it is. The 71 hardly distorts sigs when nb is on and it does a great job filtering out the leaking pole insulator down the block but the 756 grossly distorts sigs when nb is enabled and anything over medium or weak sigs are present. Some schottky or hot carrier diodes may make for superior blanking, the 71 will be the test bed for both rigs nb sections.
So I get it home and fired up, immediately noting it seemed to have a narrow cw filter installed (yay!) and the bespoke issues. The volume/rf gain knob is fooched so the volume pot has no rotation stop, and the pbt knob was a bit bent, I surmise both were victims to shipping via one of the "drop it or you're fired" companies.
I've been a fan of these rigs since dirt was new, had like 10 of them over the years, and often wondered if I'd ever get rid of the surplus of parts to mod them with, to include a rom board with programming to go from 10kc to 32mc plus a newer battery, stock they tune 100kc to 30mc. The issue here is many Icoms of the era need a good cmos battery or the radio literally forgets how to run if the battery dies before replacement.
Icom stopped building these things a few decades ago and some of them are from the mid 80s so if the cmos battery is original, well, you have been warned. So I opened the rig up to install the rom board and see if it had a cw filter, sure enough an optional Icom cw filter (worth about $50) was in place and the innards were very clean to boot.
Something I almost always do with a new rig is check to see if the various screws are snug, and this time the chassis was fine but each and every pcb was just a bit over finger tight. I wondered how that works if it was like that all the way from Hirano-ku, Osaka, 547-0003, Japan, but I tightened them up and it seemed to quiet down some odd but brief pll/vco/cpu noise it had at first startup that has yet to reappear.
The addition of the new rom board went fine and the initial startup after brain surgery showed it worked fine too, still had the same memories it had when I put the board into a static proof bag years ago. Now this baby tunes all the way down to about 9.4kc in cw mode. Copied wwvb (60kc) last nite with about 10ft of wire fed into a Grove TUN3 (if you remember those) and am fairly impressed with the rig, shamefully lacking a fish finder unlike most of my other rigs.
So this one is going to get the knobs sorted, a fresh alignment, and various mods, some of wich still have parts for.
One of the mods is to replace the pn rf bandpass switching diodes with pin types; the illustrious MI204 PIN diode, bought a mess of them from Icom years ago. These diodes have a much longer carrier lifetime than standard pn diodes, if the rf passing thru the diode isn't high enough frequency, the diode can contribute to imd.
See here for some empirical data on diode caused imd;
https://www.radioamatore.info/attachments/508_TS-940%20-%20PROMOTIONAL%20BROCHURE.pdf
Above say 11mc the as-installed diodes work great, below they start to contribute imd to a slight degree. Replacing the bandpass diodes for all ranges below 11mc will improve performance but not to a startling degree. More or less I just want to use the parts for what I bought them for.
Below 3mc, Icom used the MI204 diodes so they don't have to be replaced, just 3mc to 11mc bandpasses.
The next mod will be a better IF filter for am mode, better as in there is none as stock. The Icom R70 had enough slots for filters for most every mode, the 71 gives you two optional slots, one in the 9mc IF strip and the other in the 455kc strip. The filter I propose here will be around 6kc wide and as it's a monolithic filter, looking like a large canned crystal, will be soldered in the 9mc strip, replacing a cap. I do have a proper Icom 9mc 6kc wide xtal filter but I don't wanna have mini coax going all over, wich that would necessitate.
Then the neat mod, an infinite impedance detector in place of the simple diode detector as present. A good diode detector is fine but a infinite z detectors finer.
See here for more;
http://www.pan-tex.net/usr/r/receivers/elrpicamdetect.htm
Another mod is the nb diodes, the 71 has much better nb action than my other project, Project IC756, and that should not be, yet it is. The 71 hardly distorts sigs when nb is on and it does a great job filtering out the leaking pole insulator down the block but the 756 grossly distorts sigs when nb is enabled and anything over medium or weak sigs are present. Some schottky or hot carrier diodes may make for superior blanking, the 71 will be the test bed for both rigs nb sections.
10
Amateur Radio / Project 756 Pro
« on: October 26, 2022, 2158 UTC »
Perusing QTH one day a few weeks ago, an advert touted a bespoke IC-756 PRO hf rig at a tantalising price. Sad to say it was spoken for, listed as sale pending, I pm'd the proprietor and asked to be put on "the list" if the deal fell through. Needless to say the deal fell through and a very clean almost new looking 756 Pro made its way to new ownership.
Total cost with shipping was $360 USD. Even if the tx section was gone forever the Pro series make for outstanding rx rigs, plus they have that neat fish finder! So $360 for a rig with a fish finder and the same dsp chip as the illustrious JRC NRD 545 was, to put it bluntly, a steal.
It seems this rig as delivered indeed had tx issues, and I immediately recalled similar issues with other Icom rigs from past experience, particularly the 746 series. Sad to say the same issue also affects the 756 Pro series. To wit, static or rf can impinge upon the rx grounding silicon innards (activated when in tx mode) and eat them. They're in line when the rig is off, and when an antenna is connected anything coming down that antenna can pop the doodads, due to the Icom's rx/tx switching scheme. After testing (apply rx max attenuation via the front panel button and if the tx is good with the rx attenuator enabled, well, you have the disease) this rig def had "the disease".
This is a link to a fix of the malady;
https://www.youtube.com/watch?v=EPnglEOLChE
So the rf section in question was investigated and bad diodes and a transistor were noted and replaced. In this condition the receiver section is active during tx and puts all sorts of garbage into the tx signal, it also attenuates the rx signal. This repair fixed the tx howling issue. Note the component placement and road map of the Pro differs slightly from the Pro 3 but you can figure it out as they do the same job. Enough about that, done and done, sorted.
But wait!
The original Pro flavour (subsequently remedied in the Pro2 and later rigs) was designed with another malady that often went unnoticed! Some early adopters of the OG (Original Gansta) Pro noted a weak audio trace of band activity present below the much stronger audio as delivered by the filter setting. In my case the rig would have several kc of the band tuned to present in the audio, this is best heard via headphone but it was present and hard to ignore once you knew what it was. There is a well founded fix for this;
"Correcting the IC756Pro Noise Blanker Drive-Signal Leakage Problem"
https://www.ab4oj.com/icom/756pro_nb/main.html
HA HA! Listen to the rumble! HA HA!
This is a simple fix consisting of a single lytic cap, and the dif is night and day, seriously. Once modded the rig has none, nada, zilch, zero, null, of the garbage present in the audio all the unmodded rigs have. Enough about that, done and done, sorted.
Then on to some mods to enhance longevity of Project 756 PRO.
The inputs of most modern hf rigs have some form of impulse suppression, a gas discharge thingy or two, most commonly the input to the rx section, and the PRO has such, but what about the dual UHF socket inputs? No protection offered to the tx section at those menacing sockets, so some gdts (gas discharge thingy) good for a bit over 100w were placed across the UHF sockets; center terminal to nearby ground.
https://www.littelfuse.com/products/gas-discharge-tubes/low-to-medium-surge-gdt.aspx
Enough about that, done and done, sorted.
Ok but what about the 12v dc input?
What about that?
What if the psu goes wild and delivers 20v or more?!?
Well, for that you employ a mov, a metal oxide varistor, a resistor that changes resistance when confronted by a voltage over a certain set value;
https://en.wikipedia.org/wiki/Varistor
I selected a 20v mov for that duty and now the PRO is about as well protected from external threats as can be cheaply afforded. Enough about that, done and done, sorted.
So in summary here we are with a running Icom IC-756 Pro on the cheap, and as you might have suspected, more mods are forthcoming!
Total cost with shipping was $360 USD. Even if the tx section was gone forever the Pro series make for outstanding rx rigs, plus they have that neat fish finder! So $360 for a rig with a fish finder and the same dsp chip as the illustrious JRC NRD 545 was, to put it bluntly, a steal.
It seems this rig as delivered indeed had tx issues, and I immediately recalled similar issues with other Icom rigs from past experience, particularly the 746 series. Sad to say the same issue also affects the 756 Pro series. To wit, static or rf can impinge upon the rx grounding silicon innards (activated when in tx mode) and eat them. They're in line when the rig is off, and when an antenna is connected anything coming down that antenna can pop the doodads, due to the Icom's rx/tx switching scheme. After testing (apply rx max attenuation via the front panel button and if the tx is good with the rx attenuator enabled, well, you have the disease) this rig def had "the disease".
This is a link to a fix of the malady;
https://www.youtube.com/watch?v=EPnglEOLChE
So the rf section in question was investigated and bad diodes and a transistor were noted and replaced. In this condition the receiver section is active during tx and puts all sorts of garbage into the tx signal, it also attenuates the rx signal. This repair fixed the tx howling issue. Note the component placement and road map of the Pro differs slightly from the Pro 3 but you can figure it out as they do the same job. Enough about that, done and done, sorted.
But wait!
The original Pro flavour (subsequently remedied in the Pro2 and later rigs) was designed with another malady that often went unnoticed! Some early adopters of the OG (Original Gansta) Pro noted a weak audio trace of band activity present below the much stronger audio as delivered by the filter setting. In my case the rig would have several kc of the band tuned to present in the audio, this is best heard via headphone but it was present and hard to ignore once you knew what it was. There is a well founded fix for this;
"Correcting the IC756Pro Noise Blanker Drive-Signal Leakage Problem"
https://www.ab4oj.com/icom/756pro_nb/main.html
HA HA! Listen to the rumble! HA HA!
This is a simple fix consisting of a single lytic cap, and the dif is night and day, seriously. Once modded the rig has none, nada, zilch, zero, null, of the garbage present in the audio all the unmodded rigs have. Enough about that, done and done, sorted.
Then on to some mods to enhance longevity of Project 756 PRO.
The inputs of most modern hf rigs have some form of impulse suppression, a gas discharge thingy or two, most commonly the input to the rx section, and the PRO has such, but what about the dual UHF socket inputs? No protection offered to the tx section at those menacing sockets, so some gdts (gas discharge thingy) good for a bit over 100w were placed across the UHF sockets; center terminal to nearby ground.
https://www.littelfuse.com/products/gas-discharge-tubes/low-to-medium-surge-gdt.aspx
Enough about that, done and done, sorted.
Ok but what about the 12v dc input?
What about that?
What if the psu goes wild and delivers 20v or more?!?
Well, for that you employ a mov, a metal oxide varistor, a resistor that changes resistance when confronted by a voltage over a certain set value;
https://en.wikipedia.org/wiki/Varistor
I selected a 20v mov for that duty and now the PRO is about as well protected from external threats as can be cheaply afforded. Enough about that, done and done, sorted.
So in summary here we are with a running Icom IC-756 Pro on the cheap, and as you might have suspected, more mods are forthcoming!
11
Equipment / Sometimes a blob is better.
« on: May 04, 2022, 2044 UTC »
A HAM friend and I were discussing antennae of various bands and configurations one day. He mentioned once having a 600ft dipole up for a while, the center insulator up about 75ft on the tower. The ends were secured to some fencing used to pen the cattle. I was awestruck by this wonderous dipole revelation and asked how it performed, expecting legendary dx from such a monstrosity.
Nope.
He ran it on all the lower bands and it worked ok but not much better than the dipoles had had curt for each band, and expected it to be the cats meow on 10m as that was the band he had no antenna cut for. He heard no one on 10m and apparently no one heard him despite hours of calling. He wondered wtf was going on as he had multiple wavelengths of dipole out there to get massive gain on 10m but nope, nada, zilch.
So he finally ran a antennae sim and saw wtf was going on.
No one was going to hear him (nor he them) unless the receiving station was directly in line with the legs of that fabulous dipole. if he had simply moved the legs so it beamed, for example, into JA land he might have the killer signal in Tokyo. Did I mention when the wind blew, or even worse a storm was imminent, you could arc weld with the socket at the end of that titanic dipole's coax? When he saw that he decided it was a bit too dangerous of an antenna to let live.
Then as he was still speaking I recalled the simple 2wl wire I ran on 11m, up about a wavelength. A guy across town had me s9 plus on that antennae while a guy two blocks from him never heard me and wondered who he was talking to - yet I could hear them both fb, several others in town couldn't hear me either. All could hear me when I went vertical.
I modeled a 2wl wire on 10m and noted the many and deep nulls, explaining the reception oddity noted, and here I thought my breath just smelled bad.
So.... sometimes an undefined blob of rf (here meaning a halfwave dipole or wire) is better than rf pattern with steep jaggy edges, depending on what one wants to do with it of course.
Nope.
He ran it on all the lower bands and it worked ok but not much better than the dipoles had had curt for each band, and expected it to be the cats meow on 10m as that was the band he had no antenna cut for. He heard no one on 10m and apparently no one heard him despite hours of calling. He wondered wtf was going on as he had multiple wavelengths of dipole out there to get massive gain on 10m but nope, nada, zilch.
So he finally ran a antennae sim and saw wtf was going on.
No one was going to hear him (nor he them) unless the receiving station was directly in line with the legs of that fabulous dipole. if he had simply moved the legs so it beamed, for example, into JA land he might have the killer signal in Tokyo. Did I mention when the wind blew, or even worse a storm was imminent, you could arc weld with the socket at the end of that titanic dipole's coax? When he saw that he decided it was a bit too dangerous of an antenna to let live.
Then as he was still speaking I recalled the simple 2wl wire I ran on 11m, up about a wavelength. A guy across town had me s9 plus on that antennae while a guy two blocks from him never heard me and wondered who he was talking to - yet I could hear them both fb, several others in town couldn't hear me either. All could hear me when I went vertical.
I modeled a 2wl wire on 10m and noted the many and deep nulls, explaining the reception oddity noted, and here I thought my breath just smelled bad.
So.... sometimes an undefined blob of rf (here meaning a halfwave dipole or wire) is better than rf pattern with steep jaggy edges, depending on what one wants to do with it of course.
12
Utility / Russian mil comms info on innernets
« on: March 12, 2022, 1909 UTC »
https://cidxclub.ca/ukraine/
multiple links to informative sites
https://rusi.org/explore-our-research/publications/commentary/russian-comms-ukraine-world-hertz
excellent overview on the festivities so far, and as they like to say in mother russia, vsyo na bumage
multiple links to informative sites
https://rusi.org/explore-our-research/publications/commentary/russian-comms-ukraine-world-hertz
excellent overview on the festivities so far, and as they like to say in mother russia, vsyo na bumage
13
Shortwave Broadcast / 9420 Helliniki Radiophonia
« on: February 03, 2022, 2103 UTC »
9420 Helliniki Radiophonia from Avlis 150 KW, just making it over the background noise with Greek music. 2101Z 03FEB22
14
General Radio Discussion / A WARNING TO UKRAINE BASED RTL-SDR HOBBYISTS
« on: February 03, 2022, 2040 UTC »
"While we usually don't encourage politics on this blog, with the possibility of a Ukraine invasion by Russia we just wanted to issue a general warning to Ukrainian SDR owners. Last year we saw Stanislav Stetsenko a resident of Crimea arrested by the Russian Federal Security Service under suspicion of being a Ukrainian informant. The evidence against him was that he was an aviation and plane spotter hobbyist who used RTL-SDRs for tracking and listening in to aircraft communications - something of which many of us do in safety.
Back in June 2021 Stanislav was facing 25 years in prison. We still don't know what has happened to him. If anyone local has heard any updates please let us know."
https://www.rtl-sdr.com/a-warning-to-ukraine-based-rtl-sdr-hobbyists/
shades of the former soviet onion!
Back in June 2021 Stanislav was facing 25 years in prison. We still don't know what has happened to him. If anyone local has heard any updates please let us know."
https://www.rtl-sdr.com/a-warning-to-ukraine-based-rtl-sdr-hobbyists/
shades of the former soviet onion!
15
Shortwave Broadcast / RHC 11760 2215Z 11DEC22
« on: January 11, 2022, 2223 UTC »
RHC 11760 2215Z 11DEC22
Rousing speech from Dan Ortega of Nicaragua into solo by yl.
-81dBm sigs
ai yi yi!
Rousing speech from Dan Ortega of Nicaragua into solo by yl.
-81dBm sigs
ai yi yi!
