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Antenna problems...


Jack, W8TEE
 

All:

Several months ago a Spring storm took my 80-10M EFHW down...again. Last Thursday Al, AC8GY, brought his drone over with its hook attachment and we got the antenna up again, this time higher than before. I made several contacts with it over the weekend and I was a happy camper.

Al came back on Sunday with his VA and did a scan. Since my antenna is identical to his, we should have similar scans. Not so. My resonance points weren't nearly as deep or sharp as his. Because the antenna was new, we started at the gas tube lightning arrestor...looked good. There are two other breaks in the coax to get around obstacles in the house and those looked good. The final link was the shack's antenna switch; a popular brand and not cheap. That was the problem. I had a used switch I picked up for $5 at a hamfest, threw it in place, presto-chango--perfect! Al took the old switch home to see if a cleaning might save it. Turns out that there was some corrosion on the contacts, which raised the resistance to 10Ω. When you run QRP a lot of the time, throwing heat out instead of a signal is no bueno.

As I've said many times before, my domain is mainly software and I would never have noticed this problem and, if I did, I don't have the EE sleuthing skills that Al has. It might be worth checking your system. If you don't have a VA, perhaps someone in your club does. I think I'm going to recommend a purchase of one for our club...could be useful for our club's FD's, too.

Anyway, when I get my current project done, I look forward to getting back on the air again!!

Jack, W8TEE

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Jack, W8TEE


Viktors Miske
 

Now this is what the hobby is all about! Thank You 


Gordon Gibby
 

What a good pick up. I would never have thought of that.  And to recognize it from looking at a sweep plot is pretty slick


On Aug 17, 2020, at 13:25, Viktors Miske <unclevic7@...> wrote:

Now this is what the hobby is all about! Thank You 


Jack, W8TEE
 

Hi Gordon:

Al is a physicist by training, but a really good EE-type, too. He took one look at the plot and said: "That's not right." I nodded like I knew something...Whereupon he immediately did a TDR test using the same VA and that confirm there was a problem. I learn something new everyday...but I'm finding I forget it just about as quickly.

The goods news of this aging problem: I can have my own personal Easter egg hunt!

Jack, W8TEE

On Monday, August 17, 2020, 1:28:35 PM EDT, Gordon Gibby <docvacuumtubes@...> wrote:


What a good pick up. I would never have thought of that.  And to recognize it from looking at a sweep plot is pretty slick


On Aug 17, 2020, at 13:25, Viktors Miske <unclevic7@...> wrote:

Now this is what the hobby is all about! Thank You 

--
Jack, W8TEE


Ken Hansen
 

I encourage your club to consider such a purchase. My local club bought a RigExpert AA-600 to allow us to check repeater sites, and it has become the most popular club asset, loaned out nearly every other week to a member.

Ken, N2VIP

On Aug 17, 2020, at 08:23, Jack, W8TEE via groups.io <jjpurdum=yahoo.com@groups.io> wrote:

If you don't have a VA, perhaps someone in your club does. I think I'm going to recommend a purchase of one for our club...could be useful for our club's FD's, too.


Curt
 

Respect that everyone who owns a ubitx on the globe may not possess an exotic antenna analyzer. At a minimum, measure and record the swr of each antenna on the bands you use it. Record the data somehow, I use a spreadsheet.  The nano vna is another idea, these are amazing being low cost. Of course club and friends resources can be nice.

73 curt


Ken Hansen
 

Did I somehow not respect that?

Are we to limit our discussions to things affordable by ALL hams - no matter their circumstances - around the globe?

Are we certain that ALL list members can afford a uBitx? Certainly for some it is an aspirational item, does it disrespect them to discuss the uBitx, an item they can't afford?

Doesn't HF Signals offer an "Antuino"?

On Aug 17, 2020, at 16:15, Curt via groups.io <wb8yyy@...> wrote:

Respect that everyone who owns a ubitx on the globe may not possess an exotic antenna analyzer.