We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissible in your locale.

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - R4002

Pages: 1 ... 22 23 24 25 26 27 28 29 [30] 31 32 33 34 35 36 37 38 ... 197
436
Iíve browsed through the Yahoo group and the UK guys on transmission1.  Seems like the Maxon PC-50 and Radio Shack 5 channel HTs were sold in the UK and well.  Seems like they werenít very popular over there though. 

Iím thinking about either swapping the antenna connector for SMA as recommended, or putting a (long) telescopic whip in.  The TRC-512 radios would be much easier to do an antenna upgrade on.I was also able to find the TRC-512 service manual online. 

Given the significant range increase the antenna upgrade experiments produced I am hopeful that I can bring these radios to the 1/4 or so mile range I want.  I donít want further range for the reasons SIGMA mentioned - super low power means lower probability of intercept (unless the people doing the intercepting are *very* close). 

Iíve thought about grabbing a couple MT1000s or similar Motorola lowband HTs, include the 49 MHz freqs, 6 meter stuff, the 47.420 MHz Red Cross frequency and some others.  Several utility companies in my area use 48 MHz and 49 MHz frequencies (49.580 MHz and below)...and the state Department of Transportation operates an extensive network on 45 MHz/47 MHz, with dozens and dozens of repeaters and lots of simplex use.

Iím sure there are clear frequencies in the 43/44 MHz region but there are several heavy construction contractors using those bands...and Iím not going to use the power companyís lowband frequencies for obvious reasons...

For now Iíll continue to experiment with short range/low probability of intercept purpose stuff on the 49.820 - 49.900 MHz band...49.875 being my primary frequency for now.

437
I picked up a pair of Maxon PC-50 5 channel 49MHz band FM transceivers (theyíre actually made by Midland apparently).  These radios are very similar to the Radio Shack TRC-512 and TRC-503 5-channel FM walkie talkies - same channel plan, same circuit board, etc.  The Maxon radios have removable antennas (!!) and, of course, theyíre rubber ducks.

I did some basic range testing with the stock antennas and got about 90-100 meters away before the signal started dropping out.  I replaced the rubber duck on one with a 50-foot piece of wire and the range went up to 400 meters (1300 feet, around 1/4 of a mile) before the signal started dropping in and out.  This is in a heavily built up area too.  I used 49.875 MHz as it appears to be the less-used of the 49 MHz frequencies.  The Maxon and RS radios use a standardized channeling plan,

Channel A - 49.830 MHz
Channel B - 49.845 MHz
Channel C - 49.860 MHz
Channel D - 49.875 MHz
Channel E - 49.890 MHz

But my research indicates there is no official channel plan, only the band limits per Part 15: 49.820 MHz - 49.900 MHz.  Commercial/consumer equipment is limited to 10,000 microvolts per meter at 3 meters.  Baby monitors use random channel plans, often with 2 channels - 49.850 MHz and 49.870 MHz are popular pairs, as are 49.835 MHz and 49.865 MHz.  Yes, they are still making regular 49 MHz FM baby monitors today, most of them are 2 or 3 channel units...again with arbitrary channel plans (49.830 MHz, 49.850 MHz, 49.870 MHz seems to be pretty common too).

Iíve driven around with my scanner and have noticed three different open mics/baby monitors within a mile radius of my house on 49 MHz.  Two of them are on 49.830 MHz and the other is on 49.860 MHz (it sounds just as strong on 49.865 MHz, however...maybe itís closer to 49.8625 MHz?).  The 49.860 signal is strongest in the downtown central business district away from residences and doesnít have background noise and people talking like baby monitors do.  Itís not a birdie, multiple radios hear it....and it has the range youíd expect from a 49 MHz monitor transmitter...

One of the 49.830 MHz ones carries a pretty impressive distance, and this is with a scanner and an antenna tuned for 150 MHz.  Side by side comparisons between the Maxon 49 MHz walkie talkies and the scanner show that these little HTs have excellent sensitivity.

I plan on replacing the stock rubber ducks with telescopic whips and maybe getting a pair of RadioShack TRC-512 49 MHz radios, since they come with telescopic whips that could easily be upgraded.

The rules also state that while consumer gear is limited to the 10,000 microvolts/meter at 3 meters...hobby or home built equipment can transmit up to 100mw (measured at antenna terminals at the highest level of modulation) on any frequency within the 49.82-49.90 MHz band using any modulation type as long as it stays within the band.  Certainly a beacon opportunity there. 

Anyway, I see equipment on this band as serving a niche communications need.  FRS radios, MURS, and other VHF/UHF bands (even handheld CB radios) carry a lot further than these 49 MHz rigs do.  Cheap intra-squad radios for militia types maybe?


438
It seems like a lot of stations broadcast just above or below the limits of the various SWBC bands.  It doesnít help that the band limits seem to be slightly different according to various sources...and then you have variations from country to country.

WWCR on 12160 kHz / 12.160 MHz is a good example.  Apparently 25 meters is 11600 kHz to 12100 kHz.  There are also stations that broadcast below the 11.6 MHz ďlimitĒ. 

49 meters and 60 meters appear to be even more fluid as far as shortwave broadcasters using out of band frequencies...

439
Hope you werenít too badly hit after all is said and done (with that storm anyway).

The band has been kind of meh lately, although I did catch KHB36 and KHB37 mixing together almost perfectly yesterday morning on 162.550 MHz.

440
49 MHz band (49.820 MHz to 49.900 MHz, no official standardized channels...) baby monitors, wireless mics, etc. are still newly made and sold in 2019.  Iíve found 2-3 different monitors within 1 mile of me and thatís just driving around with a scanner. 

https://youtu.be/gsgtZBfHRK4

and

https://youtu.be/6Q4iNFKAwN4



https://www.hfunderground.com/wiki/index.php/Part_15#15.235_Operation_within_the_band_49.82-49.90_MHz




441
It appears that theyíre off the air or have QSYed to another (currently unknown) frequency. 107.7 FM is currently clear - and it was this morning as well.

442
Is the flooding/storm surge from Dorian bad down there?

The band was dead this morning.  Nothing on 162.400 or 162.550 even. 

443
Virginia House Radio 107.7 MHz FM Richmond, Virginia 6 Sept 2019

Still going strong at 0645 local time 6 September 2019 in downtown Richmond with ďCity On The HillĒ some good old timey banjo music. SIO 555 at best points...now experiencing some major QRM as I type this (0647 local, likely due to distant station QRM, possibly WTOPís simulcast on 107.7 MHz or WMOV-FM).  SIO 444 now.  Good signal with a few moments of dead air at 0648 local....then more music and positive ID by OM - Virginia House Radio Richmond Virginny 0648/0649 local with music underneath - always good to hear Virginia House Radio on 107.7 FM!

444
Heard stations on all 7 WX frequencies yesterday morning and this morning, lots of mentions of Hurricane and Tropical Storm conditions, especially when listening to the stations covering coastal Virginia and North Carolina.  Noticed that 162.450 MHz was really messy at one point, generally KZZ28 is the clear winner but at points it was almost a pure hetrodyne.  WNG586 on 162.500 MHz out of Henderson, NC was nearly full quieting in my receive as well.


445
They're also still quieting 107.9 MHz pretty well.  When I checked this afternoon during lunch break I could hear bits and pieces of WBQK (itself a simulcast of WXTG-FM out of Virginia Beach, VA) out of West Point, VA, but for the most part the 107.9 FM frequency was quieted.  They're throwing a wide FM signal for sure.

Not necessarily a good thing.

Exactly.  WBQK isn't exactly a local station but still.  I think the station on 107.7 FM is throwing a wide signal out there, or they're closer to 107.75 or 107.8 MHz instead of 107.7 MHz.   I need to do more sleuthing / monitoring around with my PL-660 instead of my car radio (which can only do the FM band standard 200 kHz steps).   They sound good on 107.7 on all receivers I've used though. 

I checked this afternoon around 1300 local time and they were playing music.  Yesterday at 1620-1630 local time I heard what sounded like a preacher in a church (could hear people in the background coughing and chattering from time to time).  The preacher was offering his prayers for [list of absolutely everyone].  Literally at least 10 minutes of "and pray for the..." - was still going when I switched the car off and went inside. 

They do have an interesting mix of material, the stuff I heard yesterday could very well have been live or very recently recorded.  [/list]

446
A lot of the stuff I've heard was obviously recorded with basic equipment in a church somewhere...lots of variation in audio quality and volume.  They've also played what sounded like old vinyls (complete with lots of pops and static cracks, etc). 

They're also still quieting 107.9 MHz pretty well.  When I checked this afternoon during lunch break I could hear bits and pieces of WBQK (itself a simulcast of WXTG-FM out of Virginia Beach, VA) out of West Point, VA, but for the most part the 107.9 FM frequency was quieted.  They're throwing a wide FM signal for sure. 

447
Back to bluegrass and fiddle playiní (live) recordings at 1210 local time. 

448
Right?

Checked 107.7 FM again around 0645 local time (1045 UTC) and music was being played, sounded like old fashioned baptist church music.  Good signal SIO 444 or better.  Fully quieting my receiver on 107.9 MHz as well.  No ID heard on 107.7 MHz - presumed Virginia House Radio FM pirate station Richmond, VA.

449
I tuned back in to 107.7 FM at 1210 local (1610 UTC) 27 August 2019...and only heard a carrier.  Unmodulated as far as I can tell...107.7 MHz is quieted. I checked 107.9 MHz and itís also quieted, with bits and pieces of audio from a distant station breaking in at points.

Presuming itís still Virginia House Radio on the air on 107.7 FM - itís just a carrier / dead air. 

450
10/11 meters / 11 meters is active 2200 UTC 26 August 2019
« on: August 26, 2019, 2215 UTC »
Some late afternoon/early evening activity on the ΣSDR - CT/MA Border (COMMSIGMA KiwiSDR).

Several stations talking on channel 6 - 27.025 MHz AM and several other in-band channels, generally the usual AM high power CB channels (6, 11, etc.).  Locals talking on channel 31 / 27.315 MHz AM and some sporadic activity on 38 LSB 27.385 MHz LSB.   The usual local FSK bursts are also coming through nicely on 27.255 MHz...no sign of distant data bursts or telemetry on 27255 or 26.995/27.045/27.095/27.145/27.195. 

Edit:  weak FSK noted on the waterfall on 27.255 MHz - channel 23 at 2212 UTC.

Channel 20 27.205 MHz is active with AM DX traffic as I type this (2213 UTC).  Lots of fading though. 

Pages: 1 ... 22 23 24 25 26 27 28 29 [30] 31 32 33 34 35 36 37 38 ... 197
HFUnderground T-Shirt
HFUnderground House Flag
by MitchellTimeDesigns