How make AM antenna Homemade?
Andrew Kiszely
"local" AM station (WTAM, 50KW, Cleveland, OH).
Anybody have any tips on making a "homebrew" AM antenna?
(Some of us have radios that have an external AM antenna screw terminal
on the radio).
Appreciate any help!
Kazee
CommQuart
Basically a large diameter coil tuned with a 365 capacitor. Either
link couple or inductively couple to the ferrite antenna in your receiver.
Peter
Andrew Kiszely wrote in message <36C95C68...@earthlink.net>...
Danny R. Barnes
SHORT & EASY MEDIUM WAVE LOOP ANTENNA
Short and easy MW tuned loop construction, with Radio Shack parts:
Build an 18" square wooden frame, 2" wide, to wrap wire on; wrap 14 turns of thin insulated solid copper hookup wire around it (buy 100' of say #22 insulated wire, $5.00), spacing it out, and attach the ends to the leads of a variable capacitor. (You can extract the variable capacitor from a Radio Shack crystal set kit $8.00) Duct Tape the capacitor to the wooden frame of the loop.
Done!
Place a radio inside the loop, tune to a station, and wiggle the capacitor knob for maximum; there's an amazing increase in signal strength DURING THE DAY. There's not much effect seen at night because the signals are already too strong.
If the capacitor is too noisy when tuned (you have to wiggle for a sweet spot)? You could get a real one from an old radio, or buy one also at Radio Shack. The variable capacitor should be 365 pf or higher value.
Removing a turn of wire raises the frequency range of the loop; adding a turn lowers it. The thing tunes slightly less than the whole band,
This at least gets you started and you can see what you'll get.
You can also turn this into a crystal set by adding a high impedance earphone, and a diode. Wire the earphone in series with the diode and place these in parallel across the capacitor/loop.
Also check out the Select-A-Tenna from many sources on the web.
Danny
Shanon Lee Herron KA8SPW
locations. They can even supply you with an AM broad band receive
booster. The stuff is not cheep but then again it works great. One
note in doing AM distribution, DO NOT use standard FM/TV splitters.
They act as a SHORT below 5 mhz. I use PECA's models 1502A and 1504
splitters and use their antenna balun (AC-1 or AC-2)on EVERY AM
antenna. It matches the antenna to the coax and cuts the noise way
down. All their stuff can be ordered with BNC or F connectors. By the
way it is all 75 ohm impedance so use RG-6 or RG-59 preferably with a
foil shield. You can join AM and FM too. Use an outside antenna (don't
forget to ground and lightning protect), amplify the signals, strech a
"redistribution" antenna in the cieling above the area you want signals
in. I do this in a large area and serve all the radios even the ones
with loopstick antenna's. 73 Shanon KA8SPW
PECA, Inc.
(Professional Electronic Component Assembly, Inc.)
592 Winks Lane
Bensalem, PA 19020
(215) 245-1550
Mark Keith
>
> At work, many of us have trouble getting reception of our local 1100 khz
> "local" AM station (WTAM, 50KW, Cleveland, OH).
> Anybody have any tips on making a "homebrew" AM antenna?
> (Some of us have radios that have an external AM antenna screw terminal
> on the radio).
> Appreciate any help!
I'm curious, are you in a metal building or one with a metal framework?
Sounds like your building is the problem maybe more than your antenna. I
can't imagine not being to pick up a 50 kw station anywhere in that
local area, unless you are shielded from the signal by metal or
something. Most any decent AM radio with a ferrite antenna should be
good enough. If no built in ferrite antenna on the radio, I'd try one
that has one. If no good, you may need an outdoor antenna of some type.
The built in ferrite antennas are normally quite good and should do the
job if not blocked. MK
Smitty
>
> Give PECA a call and ask for spec sheets.
What's a PECA? Do they have a web site?
Smitty.....
Richard Harrison
At work, many of us have trouble getting reception of our local 1100 khz
"local" AM station (WTAM, 50KW, Cleveland, OH).
My 1959 broadcast allocations book shows KYW in Cleveland with 50 KW on
1100 KHz.
If only the call letters have changed, to WTAM, the station operates
with an eccentric directional pattern, directed Southward to cover Ohio,
West Virginia, Western Pennsylvania, Western New York, and parts of
Michigan, Indiana, Kentucky, Virginia, and Maryland.
If you can get any sort of an aerial outside of a shielded or shadowed
environment, you should be able to receive this station well. Walk
around with a transistor radio to find a good spot for your receiving
antenna.
Best regards, Richard Harrison, KB5WZI
Mark Keith
>
> Andrew Kiszely wrote:
> At work, many of us have trouble getting reception of our local 1100 khz
> "local" AM station (WTAM, 50KW, Cleveland, OH).
>
> My 1959 broadcast allocations book shows KYW in Cleveland with 50 KW on
> 1100 KHz.
> If only the call letters have changed, to WTAM, the station operates
> with an eccentric directional pattern, directed Southward to cover Ohio,
> West Virginia, Western Pennsylvania, Western New York, and parts of
> Michigan, Indiana, Kentucky, Virginia, and Maryland.
checked the current fcc database and they are now WTAM. I looked at the
specs, and they show 50kw, omni, with a 185 degree antenna for primary.
? "weird height". They show sec. as 50kw,omni, with a 68 degree antenna.
"appx 5/8".
Station Call : WTAM Frequency : 1100 kHz
City CLEVELAND , State: OH Country : US
N 41 16 50 W 81 37 22 File number : - Domestic status:
License
Coordination Status Canada : A Mexico : Region 2 :
Hours of operation for this record : UnlimitedDomestic Class: A
Power : 50.00000 kw Antenna RMS : 387.85 mV/m/kw@1km
Comment: PRIROITY HAS BEEN ESTABLISHED FOR OPER WITH FRANKLIN ANT WITH
ND-290 MV/M. 0
Twr tower
No. Field Phase Spacing Orient. Height Ref Sec A B
C D
1 1.0000 0.0 0.000 0.00 185.20 0 0 0.0 0.00
0.00 0.00
I guess they are using a vertical colinear??? IE: the franklin ant???
Any comments from the BC pro's? Also at 387.85 mV/m/kw@1km I would
think they are fairly stout. MK
Mark Keith
> Station Call : WTAM Frequency : 1100 kHz
> City CLEVELAND , State: OH Country : US
> N 41 16 50 W 81 37 22 File number : - Domestic status:
> License
> Coordination Status Canada : A Mexico : Region 2 :
> Hours of operation for this record : UnlimitedDomestic Class: A
> Power : 50.00000 kw Antenna RMS : 387.85 mV/m/kw@1km
> Comment: PRIROITY HAS BEEN ESTABLISHED FOR OPER WITH FRANKLIN ANT WITH
> ND-290 MV/M. 0
> Twr tower
> No. Field Phase Spacing Orient. Height Ref Sec A B
> C D
> 1 1.0000 0.0 0.000 0.00 185.20 0 0 0.0 0.00
> 0.00 0.00
>
> I guess they are using a vertical colinear??? IE: the franklin ant???
> Any comments from the BC pro's? Also at 387.85 mV/m/kw@1km I would
> think they are fairly stout. MK
Something else I noticed, If I read this thing right, it would seem that
using the new antenna they are restricted to the mv/m level that they
have using their sec. antenna, which I assume is probably their old
antenna that used to be primary. I notice they say for the primary,
nd-290 mv/m . That is about equal to their old one. Is this correct in
this restriction, or am I just reading this thing wrong? It would seem
silly to upgrade an antenna and then have to reduce power or whatever. I
would think they always run 50kw wouldn't they under normal cdx? I'll
post the sec antenna also for comparison.
Station Call : WTAM Frequency : 1100 kHz
City CLEVELAND , State: OH Country : US
N 41 16 57 W 81 37 17 File number : BL-970411AD Domestic status:
License
Coordination Status Canada : U Mexico : U Region 2 : U
Hours of operation for this record : UnlimitedDomestic Class: A
Power : 50.00000 kw Antenna RMS : 291.80 mV/m/kw@1km
Comment: AUXILIARY
ANTENNA 0
Twr tower
No. Field Phase Spacing Orient. Height Ref Sec A B
C D
1 1.0000 0.0 0.000 0.00 68.70 0 0 0.0 0.00
0.00 0.00
Mark Keith
they would save quite a bit of power by running a gain antenna to get
the same level as the 5/8 tower.Could make quite a difference in the
light bill every month. MK
--
http://web.wt.net/~nm5k
Richard Harrison
I guess they (WTAM, 50KW Cleveland) would save quite a bit of power by
running a gain antenna to get the same level as a 5/8 tower.
Broadcast stations are required to emit their licensed power regardless
of antenna gain.
A 5/8 tower is a gain radiator as compared with the usual 1/4 wave
radiator. It extends the groundwave coverage and moves the fading zone,
where the skywave competes with the groundwave and causes the fading, to
a larger ring farther away. This is a big plus.
Directional arrays with non-uniform horizontal patterns are used for
placing more of the power into areas of dense population, and for
placing nulls in the patterns towards stations` coverage areas that
might receive harmful interference from the new station arriving on the
scene.
Stations are concerned with their steep electric power bills. This has
prompted upgrading from low-level modulated rigs with inefficient linear
amplifiers to more efficient high-level modulated rigs. Further upgrades
trade high-level modulated rigs for phase-shift modulated
(high-efficiency modulated) scheme rigs, like the infamous RCA
Ampliphase.
The Southward radiation pattern for a Cleveland, Ohio station makes
sense. The U.S. market is to the South. Canada is to the North.
Advertisers are buying access to ears in the U.S. market, primarily.
Mark Keith
>
> Ampliphase.
>
> The Southward radiation pattern for a Cleveland, Ohio station makes
> sense. The U.S. market is to the South. Canada is to the North.
> Advertisers are buying access to ears in the U.S. market, primarily.
>
> Best regards, Richard Harrison, KB5WZI
in my head , between the length in degrees and wavelength. A 180 degree
tower would be a halfwave.
I guess it must be from being a monday... So the shorter sec. tower
would be appx a 3/8 wave or whatever. I thought something seemed strange
running a colinear... So you confirmed what I had thought, when they say
running 50kw , they always run the full 50kw,except I guess for
maintenance,etc. So their new tower much better than their old short
one. I wasn't sure if they ever ran a gain antenna with reduced power
and claimed the effective legal limit ERP with reduced actual power to
the antenna. Guess not on the AM BC band. MK
--
http://web.wt.net/~nm5k
Richard Harrison
I`ll post the sec antenna also for comparison.
Broadcast stations often run with a daytime radiation pattern and a
different nighttime pattern, with local sunrise and sunset times
dictating the switch. This is caused by the skywave`s ability to
interfere with distant stations at night.
At least two vertical radiators are needed to produce a non-uniform
horizontal pattern. By spacing, phasing, and current ratio between only
two towers, large variations can be made in the horizontal radiation
pattern. Multiple nulls often require more towers. But, with just two
towers you can get a large variety of cardioid, figure of eight, and
cloverleaf patterns. You can also get the slightly eccentric pattern
which was shown in my 1959 book for 1100 KHz in Cleveland, Ohio.
Mark Keith
> At least two vertical radiators are needed to produce a non-uniform
> horizontal pattern. By spacing, phasing, and current ratio between only
> two towers, large variations can be made in the horizontal radiation
> pattern. Multiple nulls often require more towers. But, with just two
> towers you can get a large variety of cardioid, figure of eight, and
> cloverleaf patterns. You can also get the slightly eccentric pattern
> which was shown in my 1959 book for 1100 KHz in Cleveland, Ohio.
>
> Best regards, Richard Harrison, KB5WZI
the stations here in Houston are directional. The big antenna farm for
Houston is south of town in Dewalt Texas. So most tend to favor the
north and whatever directions they want. The fcc database will show if
omni or directional. And will show the numbers of towers and phasing
etc. I use their data for ideas for the 160 m band. I just wish I could
put up a big tower for 160 here. I'm gonna do it if I ever move out in
the sticks. MK
--
http://web.wt.net/~nm5k
Richard Harrison
I would even question the FCC database if it shows WTAM omni 24 hours.
There is only a Great Lake and Canada to the North. Canada is a
marvelous country, but most of the advertisers that would buy time on a
Cleveland, Ohio station would pay more for a U.S. audience. Why would
any station choose to place so much power there when a more lucrative
market exists to the South and the power is available to serve it?
Anyway, the original question was about receiving a 50 KW Cleveland
station in Cleveland. No matter which directions are favored by WTAM`s
directional array (if any), and unless there is a sharp pattern null
directly in the questioner`s direction (highly unlikely) there should be
a walloping signal available to the listener if he only gets out of the
shielded spot he must be in.
Richard Harrison
But I show omni 24 hours.
I agree with Mark`s take on the FCC`s database. The only logical (?)
exxplanation that occurs to me is that a Canadian company may now
control WTAM. That used to be prohibited. Today, anything goes.
Richard Harrison
Station Call: WTAM
Frequency: 1100 kHz
Priority has been established for operation with Franklin antenna.
I guess they are using a vertical colinear? i.e. the Franklin antenna?
Mark nailed it, I think. Vertical radiators are lengthened beyond the
usual 90-degrees (1/4 wavelength) to bring down the vertical radiation
to be closer to the horizontal. Ground wave propagation is most
important to the medium-wave broadcaster. Also, reduction of high-angle
radiation causes less nighttime interference.
At a height, or length, of 180-degrees (1/2 wavelength) the current
undergoes a phase reversal in an antenna. That is, it reverses
direction. For heights greater than 1/2 wavelength, unless something is
done, the current reversal will cause a high-angle lobe to form. This
high-angle lobe causes increased fading and interference at night.
By inverting the phase with a network at 180 degrees and stacking more
antenna length at this half-wavelength point the direction of the
current will be in the same direction in the first 180 degrees and in
the added antenna length, until the addition reaches 180 degrees itself.
This increases horizontal radiation and suppresses the high-angle lobe.
The Franklin antenna is two 180-degree antennas stacked one on top of
the other and insulated from each other. A network is used to shift the
phase by 180-degrees to drive the top section from the section
immediately below it.
This is the scheme used at VHF for colinear arrays. The phase reversal
at VHF usually comes from a 1/4 wavelength short-circuit stub.
I think Mark is correct in calling the Franklin antenna a medium-wave
colinear.
Mark Keith
> I think Mark is correct in calling the Franklin antenna a medium-wave
> colinear.
The hang with that though, if they had a franklin,which I have always
thought to be colinear halfwaves,except usually run horizontal, they
should need a full wave or taller tower. Being as they show a halfwave
tower, it would seem to just be a normal 1/2 wave vertical. Which would
show many of the properties you describe compared to a 1/4 wave. But if
they were really running a franklin, seems to me they would need a 1/2
stacked on top of a 1/2 wave. So would need a 360 degree tower with a
way of seperating in the middle. And also would need a 1/4 stub I
believe to get the currents in phase. About the same as a ringo ranger
or whatever. So dunno, the franklin they describe doesn't make sense to
me with the tower they have. To get the full gain of the franklin they
also needer a wider seperation of elements to get full performance.
Having them close seperated would be a compromise. Dunno, I'm still
really not sure what they have cooking. But sounds like a normal 1/2
wave going by tower specs. MK
-
http://web.wt.net/~nm5k
Chris Maukonen
richard...@webtv.net (Richard Harrison) writes:
> Andrew Kiszely wrote:
> At work, many of us have trouble getting reception of our local 1100 khz
> "local" AM station (WTAM, 50KW, Cleveland, OH).
>
> My 1959 broadcast allocations book shows KYW in Cleveland with 50 KW on
> 1100 KHz.
Just came accross this thread. It might be interesting to note
that WTAM was the original call of that station. According to
my aunt and gradnmother, the station was originally on a piece
of land that they either bought or leased from the the farm
that my great gradparrents lived on - just outside of cleveland,
the township of Burton Ohio. I remember my father taking me up
to see the old site when I was 12 or so. Then owned by a ham.
The original tower still there. One of the old pyramid style
towers. He had his ham-shack next to the tower. Don't remember
if that was the original transmitter shack, though.
The station was then sold, I guess to the owners of KYW - then in
Chicago, and the KYW station was moved to Cleveland. This part
I am a little fuzzy on.
I know this is off topic, but when I saw the letters WTAM and KYW,
it brought back some memories.
Chris
--
========================================================================
Chris Maukonen "Change is not merely necessary
Sr. Systems Programmer to life - IT IS LIFE"
Univeristy of Central Florida Alvin Toffler
chris@.ucf.edu (407) 823 5460
Richard Harrison
Being as they show a half wave tower, it would seem to be just a normal
half wave vertical.
Yes, but they may be authorized to go with a Franklin fullwave of about
273 meters. Maybe they need the height for an FM or TV radiator ai the
top.
I wondered about the phase inversion network. A center-tapped coil with
one end to the top of the bottom section and the other end driving the
top section might do the job. The center-tap might be returned to ground
inside the center of the lower section. I`ve never seen a BCB Franklin,
but know that several have long been in use.
Richard Harrison
Richard Harrison
I know this is off topic, but when I saw the letters WTAM and KYW, it
brought back some memories.
I don`t think it`s off topic to tell us that the station was located on
land ceded by your great grandparents for the purpose of establishing
the station. In addition, when you first visited the site at the ripe
old age of 12 or so, the station was owned by a ham.
The first radio experts were hams. The first commercial broadcast
station in Houston, KPRC, was built, owned, and operated by a ham. He
was Alfred Daniels, and he stayed on with the station as an announcer
long after selling out to the publishers of The Houston Post newspaper.
KPRC was said to be an acronym for "Kotton Port Rail Center".
Stations often made up significance for their call letters, in olden
times. WLS in Chicago was said to mean "World`s Largest Store". That was
Sears Roebuck and Company, of course.
KYW, first in Chicago, later in Cleveland, and its successor and
predecessor, WTAM in Cleveland, may also have been given some supposed
call letter significance too. Someone may know.
This thread started with: How do you receive a 50KW Cleveland station in
Cleveland? It then discussed possible directional patterns for the 50KW
station. Then the discussion moved on to a Franklin antenna which may
have been authorized for WTAM. These are rare in the medium wave
broadcast band. So, what this thread has lacked in focus, it has
redeemed with interesting excursions for some of us.