Re: Topband: Help with RFI

2013-01-14 Thread Tom W8JI

I'm reposting this to the reflector:


Yes,  I do have DSL. I have a very good RFI filter on the DSL line coming 
to the modem so I think it might be a cabling problem. Everything was 
working FB until recently when I reconfigured the hardware.  I have a few 
clamshell filters and I also have some shielded cables so Monday I will do 
some substitutions and see if it helps.  The problem is not across the 
entire band. It's only below 1825.  Frequencies above 1825 don't bother 
me.


This is probably 160 meter RF triggering the modem. Common mode chokes and 
shield normally will not do the trick, because the problem is differential.


First, you need an immune modem. The best modem I found was a 2wire ADSL 
modem.


Second, filters are almost impossible to buy. Because of that, I built my 
own filter. I added peaking at the high end of DSL, which for ADSL ends in 
the upper middle AM broadcast band area.


http://www.w8ji.com/adsl_filter.htm

73 Tom

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Topband Reflector


Topband: GI-46B Revisited..

2013-01-14 Thread Robert Briggs
Gidday all..I have built around 25 aVHF amplifiers over the past three 
years using the Russian triodes, GS-35 and 31B tubes as well as GI-6 and 
7B tubes..All of these amplifiers are in daily service on 6 and 2 meters 
and trouble free..


I have looked through all the information on the GI-46B tube and a few 
things don't add up..A company in Europe uses these tubes in their 
amplifier product's...I see many retro fits in UTube clips for TL922 and 
Heathkit amplifiers replacing the 3-500Z and supposed power outputs of 
1600 watts..


Just taking the TL922 conversion to GI-46B tubes as an example the tubes 
are openly mounted with GI-7B coolers in place of the original 46B 
cooler...The film clip shows the TL922 cooling fan retained blowing 
against the tubes...I question how are they getting rid of all the heat 
produced with such a pissy setup..I would have thought the tube should 
be mounted in a box construction with a good blower and chimneys etc...


According to the Russian GI-46B specs the tube is only rated at 350 
watts anode dissipation...Most of these conversions will be running at 
close to 3kv and to produce 1600 watts output even at 50% efficiency a 
pair of tubes will have to be dissipating a lot more than the tube anode 
rating..


Obviously the sketchy information for the GI-46B supplied on the Russian 
spec sheet  must be very conservative...


I am wondering if there are any members on this reflector have used the 
GI-46B triode and what the real results are and also the cooling used..I 
am about to do a 46B 6 and a 2 meter amplifier for a client using these 
tubes..I am confident that with proper attention to the cooling etc that 
the amplifiers will turn out ok..It has been suggested that the GI-46B 
is a substitute for a 3CX800 tube..


Bob..VK3ZL..
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Topband Reflector


Re: Topband: Need help to improve DX on 1/2 acre lot from CA

2013-01-14 Thread WS6X
Message: 2
Date: Sat, 12 Jan 2013 12:49:44 -0800
From: k...@elite.net
Subject: Topband: Need help to improve DX on 1/2 acre lot from CA

Hello All,

First, I want to describe my problem. I have a 1/2 acre lot in the back
property where I install my antennas. I live in the central valley of
California which is only about 300 feet ASL. I do not live near the coast
nor live in the high desert .

Some facts regarding this station:

1. I still have not copied or worked into Europe. I have been on this band
somewhat seriously for at least 5 years



 Hi Jeff,

You will do well to scour the archives of this reflector, paying close
attention to what your nearest neighbors are saying. While I enjoy
complaining about living in the black hole as much as the next person, in
reality, the SJV is not as bad as you might imagine. So what I write is
meant to be an encouragement and to offer proof that all is NOT lost!  

My QTH is about 2 gallons of petrol south of you in Fresno, on a 120x120
city lot. My section of town is plagued with ever-present EMI, and of
course, it comes from all directions. I have never had a multi-element TX
antenna on 160 (only ever used half-slopers). I have never owned an
amplifier capable of the full legal limit. I have no room for even a short
Beverage -- although I have considered a short BOG.

I made my first DX QSO on 160 in February 1984 (KL7GKY), so I have dinked
around on 160 for a lot of years. It wasn't until the late 90s when my DXCC
total had climbed above 50 that I began to think in terms of possible.
However, it wasn't until Christmas Eve, 2005 that I FINALLY heard -- and
worked -- my first EU (OZ7YY)!

In January of 2006 I installed a rotating flag, my first RX antenna. Since
then I've used the K9AY for several seasons, I've used a 2-el phased short
vertical system, I have tried a very low dipole bent in a U-shape, I also
have a small loop. Has any of this ever produced a night and day
difference? Not on your life. I can assure you of this: every one of these
antennas at one time or another was the ONLY antenna that could hear a
certain DX station.   

My 160M DXCC stands at 178 worked (165 confirmed) in 33 Zones. I have worked
36 EU countries on 160, many of them several times over. One glorious night
in February, 2010, I worked 17 EU in the space of 4 hours. I have routinely
worked the world (including EU) with 100 Watts. I have 22 countries on 5
continents in the log operating QRP.

On the other hand, there have been evenings when I couldn't work your FM5 or
KV4FZ with a kW to save my life. You will find that condx vary all over the
map. Rick, N6RK, and Jim, K9YC (and others) hit the nail on the head... 160M
is all about commitment: commitment to improve your TX antenna; commitment
to put the time into the band so you understand how it will bite you in the
kester; commitment to many, many, many long hours straining noise just to be
sure you are at the radio when that once-in-a-lifetime moment comes your
way!

So... is Atwater the black hole of California? I doubt it! Can you
realistically expect night and day improvements with a minimum of work?
Not on your life! Can you realistically expect to earn DXCC on TB from a
small lot? You better believe it! Of course, you better read and re-read the
preceding paragraph! :o)

Good Luck,

Jim - WS6X  

 



2. I hear a few Russians but they don't hear me.
3. I heard a FM5 last few nights peaking 559, called him countleesly with no
QSO. My power is about 800 W on this band ( single 3-500 ). I am looking
into finding a single GS35 amp for all bands on HFlove that tube.
4. I don't have the capacity to erect a full size radiator on this band
although I am curious about the Titanix 160 vertical, what it is and is it
worth looking into ?
5. I have read a lot about the K9AY RX loop. I have room for is antenna but
before I construct one, what are your opinions ?
6. I also read about a 225 foot beverage run close to the ground as a RX
ant. How does this compare to the K9AY loop ?
7. What is the best short 160 vertical configuration that has the best
performance for working DX ?
8. You will notice I mentioned that I only run a single ground radial on
each band. Would adding lets say 3 more
Make the difference between night and day for TX or RX ?



I think that's about it for now...73.

Jeff K7XQ
Atwater, CA.

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Topband Reflector


Topband: Slow DX day banter

2013-01-14 Thread Bruce
Major antenna handbooks have it mostly all together.

BOG is Beverage on ground. How can this not be understood ?   On or very close 
to the earth.

Low Beverage- One that may have Deer, Elk and other creatures bumping into it.

Beverage antenna. One higher enough not to be a hazard to 2 and 4 legged 
creatures walking on the earth.


Lately I have read on the internet quite some misuse of antenna terms.

A broadcast band SWL DX posting had a BOG many feet in the air. It was 
suggested that a wire lying on the ground could be called a WOG.

Hmmm,  Maybe if it is somewhat buried, it could be called a wire in ground,  WIG
If deeper... could be a BUG.

Maybe misunderstanding comes from the question, Where is ground? , Physical 
ground is a typical reference... Electrical or conductive 
ground may be much deeper, or some where else..

How are new hams, trying to learn the code, going to learn all these initials?  
 (;  ))

73
Bruce-K1FZ
 www.qsl.net/k1fz/bogantennanotes/index.html

 
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Topband Reflector