[LCC] LCC Digest, Vol 130, Issue 4 SWR
Marcel Livesay
n5vu at att.net
Mon Sep 16 15:13:37 CDT 2019
I have found (as a fact) that if you arc the balun, this will happen .I just had to separate the wires a little and clear the arc over point. inside the balun. All is well afterward.
Marcel
On Monday, September 16, 2019 12:00:09 PM CDT, lcc-request at louisianacontestclub.org <lcc-request at louisianacontestclub.org> wrote:
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Today's Topics:
1. Force 12 EF-240 SWR shift (w5wz at w5wz.com)
2. Re: Force 12 EF-240 SWR shift (Don Hill AA5AU)
3. Re: Force 12 EF-240 SWR shift (Charles Morrison)
----------------------------------------------------------------------
Message: 1
Date: Sun, 15 Sep 2019 15:33:38 -0500
From: w5wz at w5wz.com
To: LCC <lcc at louisianacontestclub.org>
Subject: [LCC] Force 12 EF-240 SWR shift
Message-ID: <8d1f0847091ed1c11ab521ffad0ee17f at w5wz.com>
Content-Type: text/plain; charset=US-ASCII; format=flowed
The SWR minimum on my lowest Force 12 EF-240 has shifted from ~7.16 MHz
down to about 6.7 MHz. However, the curve appears very similar to
measurements taken and archived in 2015; it's just that it shifted down
in frequency. Examining the antenna with binoculars from the ground, I
do not see any mechanical damage or oddities.
This is a linear loaded type antenna. It uses a bead-balun, and has a
coil hairpin across the feed point of the driven element.
These measurements were taken in the shack, with the AA-55 in place of
the transceiver; thus the entire transmit RF path is being tested. I've
also tested at the base of the tower, such that only 125 feet of LMR400,
a PL-259-barrel-PL259 connect, and the PL-259-SO-239 connection at the
balun are involved. The results are very similar, so I do not suspect
anything amiss that is not up the tower.
I took a sweep of the antenna today and another identical antenna,
ranging from 6.0 to 8.0 MHz. That data can be found at:
http://w5wz.com/files/40mSCAN
The purple line is the top antenna in the stack, and the blue line is
the bottom antenna in the stack. Both are Force 12 EF-240.
Lower in frequency = longer elements. What could have changed to make
the antenna appear electrically longer?
Any thoughts?
--Scott, W5WZ
------------------------------
Message: 2
Date: Sun, 15 Sep 2019 17:52:42 -0500
From: "Don Hill AA5AU" <aa5au at bellsouth.net>
To: "'LCC'" <lcc at louisianacontestclub.org>
Subject: Re: [LCC] Force 12 EF-240 SWR shift
Message-ID: <000001d56c18$49223090$db6691b0$@net>
Content-Type: text/plain; charset="us-ascii"
Time to climb the tower and check it at the feed and do a visual on the
balun and coil hairpin.
Don AA5AU
-----Original Message-----
From: LCC [mailto:lcc-bounces at louisianacontestclub.org] On Behalf Of
w5wz at w5wz.com
Sent: Sunday, September 15, 2019 3:34 PM
To: LCC
Subject: [LCC] Force 12 EF-240 SWR shift
The SWR minimum on my lowest Force 12 EF-240 has shifted from ~7.16 MHz
down to about 6.7 MHz. However, the curve appears very similar to
measurements taken and archived in 2015; it's just that it shifted down
in frequency. Examining the antenna with binoculars from the ground, I
do not see any mechanical damage or oddities.
This is a linear loaded type antenna. It uses a bead-balun, and has a
coil hairpin across the feed point of the driven element.
These measurements were taken in the shack, with the AA-55 in place of
the transceiver; thus the entire transmit RF path is being tested. I've
also tested at the base of the tower, such that only 125 feet of LMR400,
a PL-259-barrel-PL259 connect, and the PL-259-SO-239 connection at the
balun are involved. The results are very similar, so I do not suspect
anything amiss that is not up the tower.
I took a sweep of the antenna today and another identical antenna,
ranging from 6.0 to 8.0 MHz. That data can be found at:
http://w5wz.com/files/40mSCAN
The purple line is the top antenna in the stack, and the blue line is
the bottom antenna in the stack. Both are Force 12 EF-240.
Lower in frequency = longer elements. What could have changed to make
the antenna appear electrically longer?
Any thoughts?
--Scott, W5WZ
_______________________________________________
LCC mailing list
LCC at louisianacontestclub.org
http://mail.louisianacontestclub.org/mailman/listinfo/lcc_louisianacontestcl
ub.org
Message delivered to aa5au at bellsouth.net
------------------------------
Message: 3
Date: Sun, 15 Sep 2019 22:31:07 -0500
From: "Charles Morrison" <cmorrison at lusfiber.net>
To: <w5wz at w5wz.com>, "'LCC'" <lcc at louisianacontestclub.org>
Subject: Re: [LCC] Force 12 EF-240 SWR shift
Message-ID: <000201d56c3f$2d97cc00$88c76400$@lusfiber.net>
Content-Type: text/plain; charset="us-ascii"
I have the Force 12 C4XL which has your EF240 on the same boom as the
tribander, with a separate feedline. After many years of faithful service,
mine went south as well. The balun.
The balun filler leached into the SO239 and shorted my input. Changed it
out with a Balun Designs 1115t. 3-5KW 1:1 balun in a box.. no problems
since. Worth the money, best baluns on the market.
https://www.balundesigns.com/model-1115-1-1-balun-1-5-54-mhz-3-5kw/
Charlie
N5WE
-----Original Message-----
From: LCC [mailto:lcc-bounces at louisianacontestclub.org] On Behalf Of
w5wz at w5wz.com
Sent: Sunday, September 15, 2019 3:34 PM
To: LCC <lcc at louisianacontestclub.org>
Subject: [LCC] Force 12 EF-240 SWR shift
The SWR minimum on my lowest Force 12 EF-240 has shifted from ~7.16 MHz down
to about 6.7 MHz. However, the curve appears very similar to measurements
taken and archived in 2015; it's just that it shifted down in frequency.
Examining the antenna with binoculars from the ground, I do not see any
mechanical damage or oddities.
This is a linear loaded type antenna. It uses a bead-balun, and has a coil
hairpin across the feed point of the driven element.
These measurements were taken in the shack, with the AA-55 in place of the
transceiver; thus the entire transmit RF path is being tested. I've also
tested at the base of the tower, such that only 125 feet of LMR400, a
PL-259-barrel-PL259 connect, and the PL-259-SO-239 connection at the balun
are involved. The results are very similar, so I do not suspect anything
amiss that is not up the tower.
I took a sweep of the antenna today and another identical antenna, ranging
from 6.0 to 8.0 MHz. That data can be found at:
http://w5wz.com/files/40mSCAN
The purple line is the top antenna in the stack, and the blue line is the
bottom antenna in the stack. Both are Force 12 EF-240.
Lower in frequency = longer elements. What could have changed to make the
antenna appear electrically longer?
Any thoughts?
--Scott, W5WZ
_______________________________________________
LCC mailing list
LCC at louisianacontestclub.org
http://mail.louisianacontestclub.org/mailman/listinfo/lcc_louisianacontestcl
ub.org
Message delivered to cmorrison at lusfiber.net
------------------------------
Subject: Digest Footer
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------------------------------
End of LCC Digest, Vol 130, Issue 4
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