See following post with same title.
Thanks Rich, very enlightening information.
From best to worst case less than 2db difference translating to a 17 microvolt spread.
I suppose 17 microvolts could make or break hearing your signal on the edge but is it worth the hassle? The table puts us at 1 km to start with.
This thread was opened by Horatio Caine, and by chance I just encountered Mr. Caine posting at Radio Talk, where he has put his Spitfire up for sale and mentioned that he is not a part 15 broadcaster.
So much for spinning our wheels on this thread.
this post was made about 2 weeks "AFTER" the RT.net for sale post. he may have changed his mind about selling it.
Thank You gentlemen for your suggestions. Yes, I am selling the Spitfire Transmitter and buy a Hamilton Rangmaster or the the SS Tran, but for now, I am just playing around with the Spitfire Transmitter to see what I can make it do.
With the supplied antenna from the manufacture, it's ATU tuned at it's peak, seems like I only got a block or two. My wife and I are talking about selling our house and move to a home with no HomeOwners Association over it. This way, I can put up about approx. 30' of Rohn Tower, with the transmitter at the top of the tower with the antenna. From what I understand, Hamilton makes an outdoor transmitter.
The 1400 channel, we'll there has been a change in plans. Somebody in 2004 filed an application for 1410 in the next county away from us. I plan on using 1710 now. For now, I was just trying to find a way to put up a antenna in the attic of the house and just see what I could make 1/10th of a watt do.
Thanks,
H.
SSTran.com also offers an outdoor version of the AMT5000, I think the designation is AMT5000X.
AMT5000EX
🙂
I think indoor antennas are something
to keep working on, just for fun.
I have mentioned in the past that I worked
with Part 15 AM for years until I knew enough
to achieve - getting the signal to leave my
front yard!
My first successful set-up had some unusual
components. The transmitter was a Ramsey
AM-1 modified for crystal control. The loading
coil was from a crystal set. And the antenna
was a 5 foot TV antenna mast. Wow. That weighed
a ton. I didn't even know about copper poles.
So I was inside an enclosed front porch with a
5 foot antenna. There was no dedicated ground
connection to the transmitter. It got about 1000
feet down the street until it faded out on the car
radio. However, oddly enough, the signal would
reappear in front of the local fire station, about
1/2 mille away. And all of that with a 5 foot pole.
It was a big thrill to see things start to happen
back then. It was fun!
Bruce
"The 1400 channel, we'll there has been a change in plans. Somebody in 2004 filed an application for 1410 in the next county away from us. I plan on using 1710 now. "
Be careful using 1710 Khz, that techically is not a part 15 approved channel unless you attenuate the signal per fcc rules.
15.219 Operation in the band 510–1705 kHz.
(a) The total input power to the final radio frequency stage (exclusive of filament or heater power) shall not exceed 100 milliwatts.
(b) The total length of the transmission line, antenna and ground lead (if used) shall not exceed 3 meters.
(c) All emissions below 510 kHz or above 1705 kHz shall be attenuated at least 20 dB below the level of the unmodulated carrier. Determination of compliance with the 20 dB attenuation specification may be based on measurements at the intentional radiator’s antenna output terminal unless the intentional radiator uses a permanently attached antenna, in which case compliance shall be demonstrated by measuring the radiated emissions.
I never understood why with 10 Kc spacing the upper end of the band would end on 1705 Kc
1700 is the fundamental frequency and 1705 is the upper limit of one sideband of a 10khz modulated carrier 1695 would be the lower limit.
That makes purrfect sense.
In that case, I'll just find a clean channel between 1620-1700. Thanks for the tip.