Valcom AM Masts

[DudeFan]

Just out of curiosity, has anyone had any experience with a Valcom AM mast either as a permanent, back-up, or temporary transmission antenna solution? I noticed two Canadian AM's are using them as rooftop back-up sites and was wondering how effective or useful they might be as a full-time use option for up to a 1kw facility.

 

[Neal]

> Just out of curiosity, has anyone had any experience with a
> Valcom AM mast either as a permanent, back-up, or temporary
> transmission antenna solution? I noticed two Canadian AM's
> are using them as rooftop back-up sites and was wondering
> how effective or useful they might be as a full-time use
> option for up to a 1kw facility.
>
Personally depending On the frequency I would get a 100-150 foot free standing
tower and put up a Unipole....
second choice if its a non-directional... I would put in 5 telephone Poles
and install a kinstar. If its a real Emergency........ get a Big helium ballon
and let out a 1/4 wave Of wire and Tune.. the atu.... No lights needed Below 200 Feet....unless your near an airport.. that would work until you can get a tower back Up or at least an inverted L (1/4 of a kinstar)
BTW Neither the Valcom nor the Kinstar are FCC certified for Directional arrays... YET. they are only Certified for Non Directionals...

 

[jammerdave]

One of our seattle stations is using one ON A BOAT. Check out this link for pics and a story about it...

http://www.dalke.com/kkol/

fmnostatic...

> > Just out of curiosity, has anyone had any experience with
> a
> > Valcom AM mast either as a permanent, back-up, or
> temporary
> > transmission antenna solution? I noticed two Canadian AM's
>
> > are using them as rooftop back-up sites and was wondering
> > how effective or useful they might be as a full-time use
> > option for up to a 1kw facility.
> >
> Personally depending On the frequency I would get a
> 100-150 foot free standing
> tower and put up a Unipole....
> second choice if its a non-directional... I would put in
> 5 telephone Poles
> and install a kinstar. If its a real Emergency........ get a
> Big helium ballon
> and let out a 1/4 wave Of wire and Tune.. the atu.... No
> lights needed Below 200 Feet....unless your near an
> airport.. that would work until you can get a tower back Up
> or at least an inverted L (1/4 of a kinstar)
> BTW Neither the Valcom nor the Kinstar are FCC certified
> for Directional arrays... YET. they are only Certified for
> Non Directionals...
>

 

[JasonW]

Allan Wiener would be so proud! -- JasonW

> One of our seattle stations is using one ON A BOAT. Check
> out this link for pics and a story about it...
>
> http://www.dalke.com/kkol/
>
> fmnostatic...
>
> > > Just out of curiosity, has anyone had any experience
> with
> > a
> > > Valcom AM mast either as a permanent, back-up, or
> > temporary
> > > transmission antenna solution? I noticed two Canadian
> AM's
> >
> > > are using them as rooftop back-up sites and was
> wondering
> > > how effective or useful they might be as a full-time use
>
> > > option for up to a 1kw facility.
> > >
> > Personally depending On the frequency I would get a
> > 100-150 foot free standing
> > tower and put up a Unipole....
> > second choice if its a non-directional... I would put in
>
> > 5 telephone Poles
> > and install a kinstar. If its a real Emergency........ get
> a
> > Big helium ballon
> > and let out a 1/4 wave Of wire and Tune.. the atu.... No
>
> > lights needed Below 200 Feet....unless your near an
> > airport.. that would work until you can get a tower back
> Up
> > or at least an inverted L (1/4 of a kinstar)
> > BTW Neither the Valcom nor the Kinstar are FCC certified
>
> > for Directional arrays... YET. they are only Certified
> for
> > Non Directionals...
> >
>

 

[DudeFan]

Funny comment. And very helpful information. We're just kicking around ideas in case the LPAM goes through and they allow cross-ownership with LPFM. Our only choice for XMTR site would be a rooftop of 1903 steel office building with a prex-existing structural steel rooftop platform. We don't feel like going through the hassles of a 1/4 wave guyed rooftop tower because that would kick us into lighting requirements and the like, and the Valcom seemed like an easy solution.. particularly if the ground plane is tied into the building structure.

> Allan Wiener would be so proud! -- JasonW
>
> > One of our seattle stations is using one ON A BOAT. Check
> > out this link for pics and a story about it...
> >
> > http://www.dalke.com/kkol/
> >
> > fmnostatic...
> >
> > > > Just out of curiosity, has anyone had any experience
> > with
> > > a
> > > > Valcom AM mast either as a permanent, back-up, or
> > > temporary
> > > > transmission antenna solution? I noticed two Canadian
> > AM's
> > >
> > > > are using them as rooftop back-up sites and was
> > wondering
> > > > how effective or useful they might be as a full-time
> use
> >
> > > > option for up to a 1kw facility.
> > > >
> > > Personally depending On the frequency I would get a
> > > 100-150 foot free standing
> > > tower and put up a Unipole....
> > > second choice if its a non-directional... I would put
> in
> >
> > > 5 telephone Poles
> > > and install a kinstar. If its a real Emergency........
> get
> > a
> > > Big helium ballon
> > > and let out a 1/4 wave Of wire and Tune.. the atu....
> No
> >
> > > lights needed Below 200 Feet....unless your near an
> > > airport.. that would work until you can get a tower back
>
> > Up
> > > or at least an inverted L (1/4 of a kinstar)
> > > BTW Neither the Valcom nor the Kinstar are FCC
> certified
> >
> > > for Directional arrays... YET. they are only Certified
>
> > for
> > > Non Directionals...
> > >
> >
>

 

[JasonW]

LPAM wire antenna alternatives

Thank you. I've never heard a bad thing about the Valcom masts, but if you want a shorter antenna, the various NDB (Non-Directional Beacon) wire antennas are viable alternatives, especially for roof-top installations. KIAL 1450, a 1 kilowatt AM station in Unalaska, Alaska uses a standard 3-parallel wire flat-top Marconi "Tee" NDB antenna instead of a tower.

Another good NDB antenna can be seen in Steve Koone KA4YMY's beacon images http://www.beaconworld.org.uk/beaconpics9a.htm . The NDB "PYG" 270 in Pageland, South Carolina (at the bottom of his page) operates at 270 kHz, so it would be even more efficient at AM band frequencies. It is supported by four wooden poles, a wire square with a wire "X" running from each corner of the square to its center. The vertical downlead (the radiating portion) runs down from the center of the "X" to the transmitter, which is mounted on the ground below.

Also, KYPA 1230 in Los Angeles is apparently still using their 80+ year old, 4-parallel wire flat-top "Inverted L" antenna mounted atop the Odd Fellows lodge building http://www.fybush.com/sites/2004/site-041210.html . The NDB antennas are better for LPAM because they are omni-directional like a tower (KYPA's "Inverted L" is somewhat directional because its radiating downlead is attached to one end of the flat-top instead of to the center). -- JasonW

 

[DudeFan]

Re: LPAM wire antenna alternatives

> Thank you. I've never heard a bad thing about the Valcom
> masts, but if you want a shorter antenna, the various NDB
> (Non-Directional Beacon) wire antennas are viable
> alternatives, especially for roof-top installations. KIAL
> 1450, a 1 kilowatt AM station in Unalaska, Alaska uses a
> standard 3-parallel wire flat-top Marconi "Tee" NDB antenna
> instead of a tower.
>
> Another good NDB antenna can be seen in Steve Koone KA4YMY's
> beacon images http://www.beaconworld.org.uk/beaconpics9a.htm
> . The NDB "PYG" 270 in Pageland, South Carolina (at the
> bottom of his page) operates at 270 kHz, so it would be even
> more efficient at AM band frequencies. It is supported by
> four wooden poles, a wire square with a wire "X" running
> from each corner of the square to its center. The vertical
> downlead (the radiating portion) runs down from the center
> of the "X" to the transmitter, which is mounted on the
> ground below.
>
> Also, KYPA 1230 in Los Angeles is apparently still using
> their 80+ year old, 4-parallel wire flat-top "Inverted L"
> antenna mounted atop the Odd Fellows lodge building
> http://www.fybush.com/sites/2004/site-041210.html . The NDB
> antennas are better for LPAM because they are
> omni-directional like a tower (KYPA's "Inverted L" is
> somewhat directional because its radiating downlead is
> attached to one end of the flat-top instead of to the
> center). -- JasonW
>


Jason:

Thanks really cool stuff. I don't feel like am that big of a radio geek anymore now that I know there are people track and taking pictures of radio -- beacons -- rather than stations!

My feeling is that the rulemaking will not go forward, anyways, but I wanted to try to get a good grasp on the necessary physical plant, just in case.

LPAM looks like it would be far more expensive and technically difficult than it would be worth for most folks. FM is much more simple.

 

[JasonW]

Re: LPAM wire antenna alternatives

With reasonably-sized antennas, height is almost a non-issue with AM (ground conductivity is the dominant factor). A low, wet pasture is better than a dry, stony hilltop. There are Long Wave NDB flat-top wire antennas that are only 20' tall and operate down to 190 kHz, so they would work even better at AM band frequencies.

With line-of-sight FM, you must always have a tall tower or building to get decent coverage, and those aren't always available or practical. Also, AM transmitters are easier to homebrew and repair because component leads, wire jumpers, and PC board traces aren't anyhere near a significant fraction of a wavelength long. -- JasonW

> Thanks really cool stuff. I don't feel like am that big of a
> radio geek anymore now that I know there are people track
> and taking pictures of radio -- beacons -- rather than
> stations!
>
> My feeling is that the rulemaking will not go forward,
> anyways, but I wanted to try to get a good grasp on the
> necessary physical plant, just in case.
>
> LPAM looks like it would be far more expensive and
> technically difficult than it would be worth for most folks.
> FM is much more simple.

 

[JasonW]

Other LPAM antenna options

DudeFan, take a look at the licensed AM TIS/HAR (Travelers Information Station/Highway Advisory Radio) stations offered by Information Station Specialists www.theradiosource.com .

These low-power AM radio stations have relatively small (often pole-mounted) whip antennas and compact ground radial systems. They have low power consumption (some are solar powered).

Some small, isolated communities already use TISs as their local radio stations. While the relevant TIS/HAR rules prohibit broadcasting music and commercials, these towns use their TISs to broadcast public events (sans commercials) such as parades. The LPAM service could simply be a version of the TIS/HAR service that allows music and commercials. -- JasonW

 

[DudeFan]

Re: LPAM wire antenna alternatives

> With reasonably-sized antennas, height is almost a non-issue
> with AM (ground conductivity is the dominant factor). A
> low, wet pasture is better than a dry, stony hilltop. There
> are Long Wave NDB flat-top wire antennas that are only 20'
> tall and operate down to 190 kHz, so they would work even
> better at AM band frequencies.
>
> With line-of-sight FM, you must always have a tall tower or
> building to get decent coverage, and those aren't always
> available or practical. Also, AM transmitters are easier to
> homebrew and repair because component leads, wire jumpers,
> and PC board traces aren't anyhere near a significant
> fraction of a wavelength long. -- JasonW
>
> > Thanks really cool stuff. I don't feel like am that big of
> a
> > radio geek anymore now that I know there are people track
> > and taking pictures of radio -- beacons -- rather than
> > stations!
> >
> > My feeling is that the rulemaking will not go forward,
> > anyways, but I wanted to try to get a good grasp on the
> > necessary physical plant, just in case.
> >
> > LPAM looks like it would be far more expensive and
> > technically difficult than it would be worth for most
> folks.
> > FM is much more simple.
>


We've got a rooftop antenna site on a ridge at the center of town for our FM facility. I'm just marinating the posibilities of co-location, which would make logistics easier, if the opportunity arose. Ground conductivity in our region is horrible. Luckily our building just celebrated it's 102nd anniversary and is built of steel going way down into the earth, so the whole building may be a convenient grounding field.

 

[JasonW]

Re: LPAM wire antenna alternatives

> We've got a rooftop antenna site on a ridge at the center of
> town for our FM facility. I'm just marinating the
> posibilities of co-location, which would make logistics
> easier, if the opportunity arose. Ground conductivity in our
> region is horrible. Luckily our building just celebrated
> it's 102nd anniversary and is built of steel going way down
> into the earth, so the whole building may be a convenient
> grounding field.

With a great metallic ground like that available, you may be able to get decent AM coverage even with a 100 milliwatt Part 15 AM transmitter. A Talking House www.talkinghouse.com or www.actradio.com would be a good, inexpensive transmitter to use (you can get them very reasonably priced on eBay), and the outdoor Antenna Tuning Unit and whip antenna could be set up in the middle of the metal roof. -- JasonW