This is a theoretical question in which I am wondering about the difference between daytime AM operation, and nighttime operation.
This is a theoretical question in which I am wondering about the difference between daytime AM operation, and nighttime operation.
At high noon, when your groundwave signal is most prominent, a calibrated Potomac field strength meter is set at 30-meters from your antenna, and the field strength reading is a perfect 24,000-microvolts / meter, in exact compliance with 15.209.
Everything continues without a change for the rest of the day, the sun goes down and darkness comes. Now what would the field strength reading be?
guess
Your first mistake is assuming it continues the rest of the day without changing,it wont. It will change constantly with the time of day, weather,temperature,humidity and proximity. At night,the noise from distant stations will exceed your 24,000 and bury your signal.The meter cant tell the difference and will measure the total signal and noise together.
If Then
IF the nighttime reading from the AM transmitter is “lost in the noise,” which of course is true and WILCOM is stating what we have experienced many times, THEN we should be able to boost power at night my some amount to still be compliant with 15.209.
What I am thinking is that we should be able to keep our signal constant across all the day/night and weather changes and still satisfy 15.209.
If my reasoning makes sense, by how much could we…
A.) increase milliWattage;
B.) extend antenna length…
and still be compliant with 15.209…?
Of course the numbers would be “ballpark estimates.”
Have One?
Unless you got a Potomac, how are you to determine you are still complying when raising the power to overcome natural signal propagation factors between the different hours of the day and night?
15.209 is NOT the only rule you have to follow. 15.219 as well, which CLEARLY says 100mW FINAL RF INPUT.
You cannot adhere to one while violating the other. You will still get tagged.
RFB
I Would Never Do This But
I have always thought it would be fun to
put a signal on one of the local channels –
i.e. – 1230 1240 1340 1400 1450 1490.
I would not do it because you would have
to be a pirate station to get any range.
However, you would be surrounded by all
kinds of signals at night. I guess it has to
do with this vision I have had in
my head all my life. The small hometown
250 watt station (back when that’s what they
were) with the little building (studio and transmitter)
the little yard in back, and the single stick out
there. Playing Big Band Music. When I was a kid in Junior High, there
was a book called, “This Is Your Announcer.”
It was the story of exactly that – a small 250
watt station on 1400 and what it was like and
how it was run in about 1950. Only two kids in the school
ever took out that book. One was me. The other
kid who took it out – well I didn’t know him then.
But sometime after that we became friends, and
we are still friends now. In fact, I just saw him
about two hours ago.
It’s just a fantasy of course. My Part 15 station has
filled this hole fairly well. Especially with the
vintage equipment it has.
It’s just a weird idea that I wanted to share just
for the humor of the thing.
Actually, all of those frequencies are in use day
and night at my listening post.
Bruce, DOGRADIO STUDIO 2
And Listening Post WPE1POI (i forgot about that)
with various receivers in use at various times.
Some of my receivers I have not mentioned on this
board:
ICOM R-70A, Yeasu FRG-7700, SONY ICF-2010,
KAITO 1103, GE Superadio, Hammarlund HQ-140X,
Hammarlund HQ-100, Sony SRF-A100, Heathkit
HR-10B, Heathkit GR-81, Grundig S-350, Grundig
S-350DL, Sony SW-20, Sony ICR-4800, Sangean
DT-400W, Sangean DT-200VX, Grundig FR-200,
ICOM IC-720A, Radio Shack PRO-30, PRO-60,
PRO-2005, Tecsun PL-380, Kenwood KT-8300
Technics ST-9030, Radiosophy HD-100, and
Sony’s AM/FM HD tuner (I can’t remember the
model number.)
Before you think I’m crazy because I went out
and bought all of these radios, I’ll explain –
many of them I got for free. It is a long long
story. But I will be the janitor/caretaker of
these radios until I pass on and they go to
another good home – I hope.
OH Yeah, I Forgot
Some of the radios don’t work.
The Hammarlund HQ-100 (Actually an
HQ-100A) looks like it was run over by
a trailer truck, although it works in the poor
to fair range. The HR-10B – I would never
use for any reason. (But I love it a lot anyway.)
The Sony SRF-A100
is cosmetically in poor shape, although I
have been trying to fix it up. The Yeasu
FRG-7700 and the HQ-140X need to be
recapped. The Grundig S-350 and S-350DL
and not working right because of very heavy
use. The 350DL is mostly dead. The 350 is
hanging on.
I also have some All American Five radios. They
all need to be recapped.
So actually a lot of these radios have issues.
I just had another one fail the other day. I can’t
remember which one…
Bruce, DOGRADIO STUDIO 2
Signed In For This
When I saw the long list of radios I had to log back on to register my absolute astonishment.
I have about six radios and fight the impulse to get some more, but now I know a guy with enough radios to fill an entire wall from floor to ceiling…..
Bruce Dog Radio Studio 2 gets the “Number of Radios Award.”
Now I’m logging off and looking through radio catalogs.
I Should Really Clarify This
It’s a funny thing. I don’t know
if the radio guys around here feel
sorry for me because of my severe
vision problem… But the kindness
of my friends has been huge. Many
of these radios were given to me,
many of them have issues, but I
consider that to be fun.
A lot of these radios are small and
are in storage. My set-up here is
sort of like a little radio museum.
One radio I didn’t mention(?) is a
Lafayette VHF/UHF public service band
monitor. Probably from the early
seventies. The model number is PF-300.
It is beautiful and works great.
Probably worthless to most people but
I love the thing. I have NEVER been able
to find any info about this radio on the
web anywhere. I am also looking for my
first 100 mW CB walkie talkie from 1967.
I am sure they are all gone. But it was
a Radio Shack TRC-22 – a 2 channel rig.
If I never find that, a TRC-33 would be
fine, too. But again, I know they must
be in land fills. I have never been able
to find them.
My ham station, listening post, and DOGRADIO
90.9/1690 are actually small low profile
set-ups – as small as I can get them to be.
I sort of want them to blend in with the
other things in the house.
It funny – but when I started in ham radio
I actually gave away a lot of gear – either
for free – or for very low cost. It was
to help other ham stations to get on the
air.
Now a bunch of radios have come back. Like
I said, I will give them a good home as
long as I can.
So I hope that explains why I have so much
stuff.
Best Wishes,
Bruce, DOGRADIO STUDIO 2
MICRO 1700 – Don’t Give Up!
I was able to find 2 of my first rigs by setting up an automatic search on e-bay. Just plug in what you’re looking for and it will automatically check for you and report every day for up to 6 months.
I found a working model of my first walkie-talkie, a 1964 100mw Lafayette HE-29C….NEVER thought I’d see one of those again…AND my first Part 15 transmitter, a Lafayette LA-23. Didn’t take that long to find, either. A couple of months maybe. Try it! (but be careful…)
Recapturing Our Youth…
Yes, I too bought a few pieces of my childhood from Ebay.
The REMCO CARAVELLE a combo AM RX/TX with mic and code key. Then there’s the Lafayette KT-195 tube broadcaster. A REMCO TINY TIM CRYSTAL RADIO, some CUB SCOUT CRYSTAL RADIOs.
I’m looking for my first real CB, a Lafayette HB-115A.
Treasure Hunting
Two things are in high demand in the used marketplace, great old radios and decent 8MM movie projectors.
A few times every year I hit the Goodwill Stores and pawn shops looking for something, and someone has always just beat me to some great find. What I suspect is that someone just like me has a head-start advantage, perhaps because of regular church attendance, and gets the good stuff.
But you should never give up. There will come a day when you are the early worm.
Cool!
Great stuff you guys! Wow, It’s amazing
you found those radios.
I had a friend in 1967 who had a five watt
Lafayette HE-20A. It was a vacuum tube base
rig. His first antenna was a coat hanger on
the front porch. He did live up on top of
a big hill. He was supposed to get an HE-20T,
but ended up with the A model instead.
I remember some of those early Lafayette radios
because people here liked them better than Radio Shack.
The old CB rigs you found interest me – in just
what they looked like.
I remember when the Lafayette DynaComm 5 walkie
talkie came out. “Five Watts You Can Hold In
Your Hand!” I remember those words in the catalog
and the picture like it was yesterday.
There was cool Radio Shack stuff too for CB.
My early things were TV DXing because my parents
had a roof TV antenna and a pretty good TV –
and then CB radio. But when a friend mentioned ham radio,
and the 75 watt Novice license, I started to go
in that direction.
I’ll try the E-bay thing – and maybe go to Church too.
Best Wishes,
Bruce, DOGRADIO STUDIO 2
More cool stuff!
“I remember those words in the catalog and the picture like in was yesterday!”
Me Too! But I wasn’t completely happy with just the memories….so about 5 years ago I attempted to find those old catalogs with an e-bay search. Success!! I now have a ’65 Lafayette catalog and a ’63 Allied on my bookshelf. Talk about memories!! I put ’em in Saran wrap to keep ’em nice. Only problem is having to unwrap them every time I want to reminisce. But it’s worth it!