Topband: Antenna terminations

2013-03-14 Thread Jim Monahan
I've covered my resistors and solder joints with GE Silicone II sealant
and have never had a problem. The curing does not impact solder joints
and I've used this product for some 20+ years.

I can't measure any resistance using it.

It cures in several hours similar to a rubbery type substance. And, it is
easily peeled back when needed.

Around here in CT, it is available in 2.8 oz. tubes in most hardware stores.

Jim, K1PX

K1PX at msn.com
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Topband Reflector


Re: Topband: Antenna terminations

2013-03-14 Thread Charlie Cunningham
Same here, Frank

I can't do Beverages on my city lot, but I do use carbon comps exposed to
the weather in my terminated KAZ receiving loops, with no apparent
detrimental effects after years in the weather.

Perhaps we shouldn't abuse electronic components (even resistors) with heat
guns?

Regards,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
donov...@starpower.net
Sent: Wednesday, March 13, 2013 1:55 AM
To: topband@contesting.com
Subject: Re: Topband: Antenna terminations

Like Tom, I install my carbon composition Beverage termination resistors
fully exposed to the weather.  I measure them annually and over a 20 year
period just a few have changed resistance outside of their marked tolerance
band.

I'm sure there are better ways to protect them, but open air has been very
reliable for me.

73
Frank
W3LPL

 Original message 
Date: Tue, 12 Mar 2013 14:01:51 -0400
From: Tom W8JI w...@w8ji.com  
Subject: Re: Topband: Antenna terminations  
To: topband@contesting.com

 Depends on the method used to provide the conductivity.  If it's carbon 
 black filled, the shrinking is goin g to push the molecules of the carbon

 black closer together and that results in a net decrease in volume 
 resistivity.  It may not matter however, as carbon filled stuff is going 
 to be in the K-ohms range in the lowest case.  Other fillers may have 
 lower values.

This is of interest to me, because I use carbon resistors and heat shrink
so 
often.

I just measured several carbon composition and film resistors, and none 
changed value with pressure (in a table vice) until they fractured.

I can't find any conductive heatshrink, either. This potential issue really

should concern all of us, because it is a serious hazard if we heatshrink 
power line leads or HV cables.

I'm not doubting the results, but the only resistors that I've seen change 
value outside of age or abuse are large carbon bar resistors when submerged

in a liquid. For dummy loads, like a Cantenna, the resistor has to be 
specially treated before spending any time submerged.

I routinely mount Allen Bradley carbon composition and Ohmite metal 
composition termination resistors right out in the open air, directly 
exposed to weather, and they stay good for years! They can look really ugly

and still test good. This isn't saying that is a good practice, just that I

haven't ever seen an issue outside of direct lightning hits. I have some 
pretty ugly resistors retrieved when redoing antenna end connections (the 
fence wire rusts with age), and they still are good!

If there is a certain brand of materials that is sensitive, it would be 
helpful to learn what it is.

I do not use metal or carbon films outside, or in high overload 
applications. BTW, some carbon films look **exactly** like carbon 
composition resistors!!

73 Tom 

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Topband: !80 deg phase inverter vs Flip transformer

2013-03-14 Thread Dave Kirk
Been reading in ON4UN low band dxing book about mulitable element receive 
arrays for 160 meters. I'm a little confused about 180 deg phase inverters, and 
flip transformers are these two the same thing?

73,Dave
W6MQI
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Topband Reflector


Re: Topband: Antenna terminations

2013-03-14 Thread Don Kirk
K1PX said,

I've covered my resistors and solder joints with GE Silicone II sealant
 and have never had a problem.


I do the same thing with my pennant termination resistors (just cover them
with GE Silicone II sealant).

73's
Don (wd8dsb)
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Topband Reflector


Re: Topband: !80 deg phase inverter vs Flip transformer

2013-03-14 Thread Tom W8JI


Been reading in ON4UN low band dxing book about mulitable element receive 
arrays for 160 meters. I'm a little confused about 180 deg phase inverters, 
and flip transformers are these two the same thing?




I never heard of flip transformers before, but in context of the 
application I immediately recognize it as different names for the same 
result. They invert, or rotate, signal phase 180 degrees over a wide 
frequency range.


Any reasonable name is acceptable as long as the text or context explains 
the function. 


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Topband Reflector


Topband: FT-1000MP service

2013-03-14 Thread Mike(W5UC) Kathy (K5MWH)
Two weeks ago today I shipped my FT-1000MP off to Byron, WA4GEG for 
service  tune -up.  The rig was back here on this past Tuesday, a total 
of 13 days including the weekend.  It came home in great shape, working 
like a champ, and with all issues addressed.  There was no effort to fix 
things that didn't need work.


I can gladly recommend this gentleman for service.  He ONLY services the 
FT-1000 series rigs.


73,
Mike, W5UC
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Topband Reflector


Topband: Pixel RF PRO-1B Loop Antenna

2013-03-14 Thread Dave Harmon
Thanks to everyone for the opinions and experience on 160 and 80mtrs with
this antenna.
If there are any more comments and experience with this unit please send
them now. 
Thanks
73


Dave Harmon
K6XYZ[at]sbcglobal[dot]net
Sperry, Ok.

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Topband Reflector