{Collins} Re: RFI problems



I don't find serious fault with what has been posted on this subject. However, there are two items that I have not seen today that will cause serious RFI. The first is a poor or non- existent station ground or station equipment incorrectly grounded.

The second is an antenna that is not matched to the radio. The chief offender in this class is the popular off-center fed dipole connected to the station with openwire or some type of twin lead. For this style antenna to function correctly, the current in the feedline must be near perfectly balanced. If this is not accomplished, the feedline becomes part of the antenna and radiates RF just like the dipole. If the feedline is brought all the way into the station as opposed to matching it outside, you will usually have a station with RF floating around. A Tuner must be used in this system.

Now ,so for as the 30L-1 and RFI are concerned; I rarely use my 30L-1 except in The Motor Home. We average 12 camping trips yearly. The 30L-1 feeds a HY-Gain 14AVQ Vertical mounted on a 12 inch post in the center of the top of the motorhome.. The roof is one solid sheet of alumium. Therefore, I have a near-perfect groundplane. I have used this arrangemeni on motor homes since 1984. I run 400 Watts out pretty consistently. In this motor home are three sensors; CO2 unit, Propane/Butane sensor and a Smoke/Heat sensor. I have never tripped any of them. Yes, I test them and they work correctly. We also operate two TVs and a Surround Soumd System.

If you are using a multi-band antenna system with traps, there is no need to use a "Tuner" in your system. If you can't adjust the various band to an acceptable SWR W/O the tuner, something is wrong.

One final comment in this regard; I have never been able to get a good ground system when my shack was on the second floor of any structure. The closest I have come is to use an artificial ground syatem.

Harold
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