2m Skip?

[K0RGR]

Thanks, Cory - my understanding of these little marvels is greatly enhanced!
The radios don't have an IF. They are little software defined radios under the covers! They use the RDA1846 chip, which is a fully self-contained transceiver on a chip. They merely add a microcontroller to run the radio's functions, and receive and transmit amplifiers. The RDA1846 takes the receive input through a pair of mixers with a 90 degree phase shift on one to produce a quadrature output. This is fed into two ADC's, which feed the built in digital signal processor.

[KC2UGV]

Thanks, Cory - my understanding of these little marvels is greatly enhanced!
The radios don't have an IF. They are little software defined radios under the covers! They use the RDA1846 chip, which is a fully self-contained transceiver on a chip. They merely add a microcontroller to run the radio's functions, and receive and transmit amplifiers. The RDA1846 takes the receive input through a pair of mixers with a 90 degree phase shift on one to produce a quadrature output. This is fed into two ADC's, which feed the built in digital signal processor.

Hmmm.... Which makes me wonder: Can you put a Arduino/RaspPi/Parralax in there to turn them into full SDR's?

[W7XF]

I concur , Corey. The Baofeng is a SDR. Although I have determined the clock reference as 32.768 KHz. But, there is what looks like a 26MHz xtal connected in series with a 10pFd cap and in parallel with a variable cap and another unspecified cap to ground.... what I did was look at the CPU's specs here.

[N8OBM]

So I'm monitoring my local repeaters with my BooFunky HT, and I'm in the bedroom.... Folding clothes! The radio is on the dresser (next to the bail money) and it stops scanning in 147.220.

147.220 is a repeater for the Pearland Radio Club, and its about 12 miles from me, but all of a sudden I'm hearing fire tones. Deer Park Pd was dispatching the FD to an unconscious person.

Now the repeater is 12mi from me, but the Deer Park PD is only like 2.

I've NEVER heard DP police dispatch on ANY frequency, and I was pretty sure they were on an 800mhz system.

Is this just a fluke thing based on the location of my radio, the weather, and the proximity of the transmitting station? I wouldn't think they would be using frequencies so close to amateur bands...

I have seen where a corroded antenna clamp can act as a simple mixer. Just add water. When I help maintain the club repeater back home we shared antenna space with a bunch of pager transmitters years ago. There were two pager transmitters that were 600KHZ apart from each other. If it was raining or very humid, When the pager transmitters were transmitting and our repeater would come up, we would get a feed back loop. our output would get cycled back into our input. If not for the delay in the controller the thing would have just howled. Instead it sounded like a cheap CB echo mic on over drive.

The other likely avenue is weak filtering. It's not at all uncommon for cities to use frequencies in VHF high and VHF low bands that duplicate the trunk systems traffic so they can more easily communicate with neighboring services. Sometimes they leave these secondary frequencies running sometimes they don't. This is what you most likely heard. Most trunked systems at very least channel hop and many are digitized like cell phones are. It's unlikely even if you did hear them, that you would be able to make heads of tails out of them. That said, If you put a big enough signal at the antenna, You will get some kind of audio out.

I used to work in the shaddows of a 300ft+ building with a 10KW FM broadcast transmitter on it. We went through about a dozen different radios before we found one that could hear anything besides the one station. We found two the worked. An old KLH desk top radio from the late 60's or early 70's and an old Heathkit AR15 receiver from 72 that my grandfather and I built. Well, OK, he built it and I mostly messed things up for him. What can I say, I was 8 at the time. We could not find a modern receiver that would work.

Archie N8OBM

[N8OBM]

Not skip, tropospheric ducting. It happens a lot in the late summer. Sometimes I hear repeaters from way up north down here in San Diego and SoCal hams QSO with hams in Hawaii on 2m.

A cool tropo-ducting story. Years ago I was talking to friend of mine across town in Ann Arbor on the 145.15 repeater. This machine needs a 100hz PL to open up. After we were talking for a few minutes I noticed the tails were a little slow and the courtesy tone was different when I stopped transmitting. It seemed that I forgot to turn my tone on and My signal was going trough a repeater on the other side of Lake Erie in Cleveland Ohio. That was a good 200+ miles away. Not bad for a 5 watt HT. It also happens pretty regularly in the FM broadcast band. My evil twin brother lives near Cleveland so I visit often. It's not uncommon to hear Detroit FM stations in summer in Cleveland.

Archie N8OBM

[K7SGJ]

A cool tropo-ducting story. Years ago I was talking to friend of mine across town in Ann Arbor on the 145.15 repeater. This machine needs a 100hz PL to open up. After we were talking for a few minutes I noticed the tails were a little slow and the courtesy tone was different when I stopped transmitting. It seemed that I forgot to turn my tone on and My signal was going trough a repeater on the other side of Lake Erie in Cleveland Ohio. That was a good 200+ miles away. Not bad for a 5 watt HT. It also happens pretty regularly in the FM broadcast band. My evil twin brother lives near Cleveland so I visit often. It's not uncommon to hear Detroit FM stations in summer in Cleveland.

Archie N8OBM

They still have radio stations in Detroit? Who gnu?

[NQ6U]

Who gnu?

Wildebeest who made that pun please excuse himself?

[N8OBM]

They still have radio stations in Detroit? Who gnu?

Even more unbelievable, They have radios in Cleveland!

Archie N8OBM

[K7SGJ]

After noticing the title of this thread, I was reminded of a kid in high school. He stood a little under six feet, and had an animated walk. We nick named him...............well.......you get the idea.

[kb2vxa]

Cleveland?