146.760 Ham Radio

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pawsrock

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Jun 26, 2005
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Jacksonville Fl.
Last night coming home I was getting splatter on the radio. I could tell it was a net and I got the impression it was from South Carolina. I was mobile at the time, so I was not able to really listen to it. The net control came on, he sounded like he was down the street. Has anyone heard this before?
Thanks
Ron Fone

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SCPD

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Yup... sure have. It's called ducting, or skip, and it happens this time every year on the VHF bands. I've been able to use a 2 meter repeater hundreds of miles from me but unable to hear our local repeater on the same frequency. Sometime back in 1996 I was living in Maryland, I was able to use a 5 watt HT and simultaneously talk through several repeaters on the East coast. With a rubber duck antenna I could key up a repeater in Maryland, Delaware, New Jersey, and New York... all on the same frequency pair. There are times when I can use a 2 meter repeater in Atlanta, from the Augusta, GA area, with a quarter wave antenna on my truck and be full quieting. Another example, when I was in the U.S. Army I was stationed in Hawaii in the late eighties. One Summer I was able to hear the California Highway Patrol on their low band VHF system as if they were local to me. If you're a licensed ham try the "magic band", AKA the 6 meter band (50-54 Mhz), and you'll really be amazed at what you can do on VHF with the right conditions.

Ducting is the reason I support using a PL tone on the repeater input, when the conditions are right our local repeater (no PL on it) can get keyed up long enough to time it out and make it totally unusable.
 

jim202

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Mar 7, 2002
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2,669
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New Orleans region
Not having heard what your talking about directly, it is hard to even call a shot as to what the
problem may be. You haven't provided any information as to what receiver you were using,
where you were located, what frequency you were listening to or any of the important details.

Being a ham myself for some 46 years or so, there is not much that I haven't seen or done. I
have worked in the two way service side and do engineering work on many public safety radio
systems around the country. It does concern me when I do hear problems about how some
ham repeaters are functioning. When I hear an issue, I do try to contact the responsible
technical people about it. This does take an effort in some cases just trying to locate who
owns the repeater.

With that all said, my first guess in trying to read between the lines here is that there might be
a possibility that the repeater has too much transmit deviation. The only way to prove this
would be to use a service monitor to measure both the TX frequency and deviation. On the
2 meter band, the TX deviation should be held to about 4.8 KHz at the most. If you go above
this setting, you do stand a good chance to cause problems to the adjacent repeaters on a
frequency either side of where it is operating.

I have found a few repeaters that have been set up by the owners with no test equipment.
In most cases, if I have the equipment with me and have the time, I do offer to take a look
at the offending repeater. Normally it only takes a few minutes to get it into adjustment
and sounding like it should. If I am rushed for time and don't have the test equipment
with me, I do offer to try and make an date to return and help.

Again with this said, there are a number of radios out on the market today that have what I
consider very poor design. Most of the radios that fall into this category are made off shore
from the US. This is not to say that there are not some very good radios made off shore.
But when I hear someone complaining, the first thing I do is ask them just what radio they
are using when they think there is a problem.

Being spoiled by working around commercial two way equipment all the time, I find myself
using the same equipment on the ham frequencies. In most cases, it is a GE, EF Johnson
or a Motorola radio that I am using.

Jim




Last night coming home I was getting splatter on the radio. I could tell it was a net and I got the impression it was from South Carolina. I was mobile at the time, so I was not able to really listen to it. The net control came on, he sounded like he was down the street. Has anyone heard this before?
Thanks
Ron Fone

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pawsrock

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Joined
Jun 26, 2005
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228
Location
Jacksonville Fl.
Frootydawg, thanks for the advice. Yes I had forgot about ducting, this is the first time I have heard it. I have just reinstalled my kenwood 2m back in my truck, so I was surprised to hear it. One day I will get on 6m, but not for a while.
Ron Fone (KG4NKI)
 
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