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So what section do you file for a minor change in?

R

Radio Bob

With the addition of the new sections in the FCC's web site I'm a bit confused. I've filed for full FM Construction permits on their site before no problem but I just want to file for a minor change and haven't been able to find where as there doesn't seem to be a section for minor changes. Anybody know? Thanks in advance
 
You're wanting to modify the license to specify a new antenna in LMS. Are you going to go H and V?
 
Actually I'll need half the transmitter output power to maintain the same ERP if I go V only. I don 't want to change anything Nothing what-so-ever except to change to vertical only everything will remain same ERP, same location, same height. ( yes I'll have to turn the transmitter output back) Try as I might in the LMS I can't find where you can file for a minor change even though the FCC's bulletins mention it as being possible in the LMS. What am I missing>
 
You need to follow these instructions. LMS is not as user friendly as the old system. FCC LMS Instructions
 

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Just wondering! Why do you not want horizontal polarization? Radios with antenna in the cord need it as well as car radios with in the windshield antennas.
 
Harvey_Dogg said:
Just wondering! Why do you not want horizontal polarization? Radios with antenna in the cord need it as well as car radios with in the windshield antennas.
Click to expand...
Exactly. Curious minds want to know. On the surface, this seems like a totally backwards move. They risk creating a pretty bad multipath environment for vehicles.
 
It has been my experience and belief that FM should have always been vertical or at least originally there should have been an option. As a boy I learned quickly that horizontal only antennas killed long distance listening on car radio's as cars all had vertical antennas only. At the same time it became clear that while antennas in the power cord were less intrusive they mostly hung down from the shelf the radio sat on so in effect were vertical also. The exception was when you hooked to the home's TV antenna in which case DX was very possible because TV has for the most part has always been broadcast horizontally. The original purpose of horizontal only transmission on FM and TV was to avoid noise . The early receivers did not reject noise anything like today's do. When the FCC began allowing FM stations to use circular polarization ( horizontal and vertical together) people were suddenly able to get stations further away. I learned this when we switched to circular polarization at a station I owned over a weekend and one of my dj's didn't know about it. His girl friend went crazy telling him things had changed when they returned from a trip because she could tell the difference and hear the station further away as they approached town. Naturally, this gave rise to the question if horizontal only wasn't very good on many radios and circular ( adding vertical ) made things better what would happen with vertical only. We got a chance to hear the difference when the FCC allowed some stations at the bottom of the dial to use vertical only to avoid interference to TV stations operating on nearby frequencies. I found that the change to vertical only did not degrade the signal in cars and most home portables which by now used collapsible antennas. I honestly can not tell the difference in signal from a circular polarized station and a vertical only when driving. ( yes some translators are allowed vertical only ) I think the bottom line is vertical only works fine and should have been allowed from the beginning.
 
During the 2nd World War the US military found that horizontal polarization went further than vertical beyond line of sight. Now as a DXer I found that tropospheric ducting allows distant FM reception in both planes many times with signals that come in strong.

So let's assume you have a translator that has an ERP of 100 Watts. You go vertical only only and save a hundred dollars a year on the power bill. But you have lost 99 Watts in the horizontal plane. Cars with windshield antennas now have trouble picking up your one Watt signal and tropospheric ducting brings in other stations and kicks your ass.

You should not do this!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
Harvey_Dogg said:
During the 2nd World War the US military found that horizontal polarization went further than vertical beyond line of sight. Now as a DXer I found that tropospheric ducting allows distant FM reception in both planes many times with signals that come in strong.

So let's assume you have a translator that has an ERP of 100 Watts. You go vertical only only and save a hundred dollars a year on the power bill. But you have lost 99 Watts in the horizontal plane. Cars with windshield antennas now have trouble picking up your one Watt signal and tropospheric ducting brings in other stations and kicks your ass.

You should not do this!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Click to expand...
Thanks for the advice. But, it's been my experience that the horizontal component isn't necessary. There are several stations in my area who operate vertical only and several FM translators as well that have excellent coverage both in my car and at home some 25 miles away Their coverage is no different than the circular polarized stations from the same area. Incidentally, my car has the windshield antenna you speak of. I think there is a irregularity between theory and actual use probably because in actual use your car and your home antennas are not exactly 90 degrees one way or another as opposed to the transmitting antenna because of curvature of the earth, winding elevated roadways etc. Ducting can kick your ass a few miles from the actual station's tower no matter what power and polarization if things are right. Just sayin
 
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Greg,

it's a Jampro JLCP single bay circularly polarized mounted atop a pole atop a building. It's nondirectional . I've tried to post more but the site keeps dropping out with a statement that it is having trouble. I'll post more later. Have a great day
 
As to the ATU I added a static choke coil from the antenna to ground plus a real knife jumper instead of the two pieces of copper strap they had cobbled between the antenna and the tuning coils. ( you might have missed that as it was hard to see ) I also tied the ground strap from the tower to the ATU box and ran a copper strap from the tower to the transmitter building and added a star ground to the building as well. I did not remove the copper wires preferring to do so when I get a bridge and set the tuning on the tower. The station is currently off air while the transmitter is being repaired. I'll probably remove the copper wire.
 
Sounds good. About the Jampro, I am imagining it is side mounted on a pole with an overall height of less than 20 feet above the building, as opposed to a larger pole or monopole. Presumably if you go vertical polarization you are thinking of a top mounted vertical element with radials. This could change antenna height, but you could account for this on the application. One thing is the typical vertical antenna will not have a grounded element, while the Jampro is grounded.

You might be happier with a top mounted vertical polarization antenna. However, the translator may not be experiencing circular polarization at its best, because the design type of the JLCP is an early implementation of circular polarization. More recent designs (including one Jampro makes) could provide higher quality circular polarization. That could be the crossed or bent dipoles or the helical.

Just want to make it clear I am not criticizing Jampro. It is the design type, not the company.

Is there a transmitter sizing or transmission line loss situation?
 
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