Re: [Elecraft] Balun BL2

2016-05-27 Thread Ron D'Eau Claire 
Keep in mind that the only source of the heating in the core is the RF power 
applied. Every watt used to make heat is a watt never radiated. 

A hot core will eventually reach its Curie temperature that causes the 
inductance to drop to a very low level. At that point it is no longer 
functioning as a balun, transformer or whatever.

73, Ron AC7AC



-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Walter 
Underwood
Sent: Thursday, May 26, 2016 8:46 PM
To: Elecraft List
Subject: Re: [Elecraft] Balun BL2

You might look at the “QRP” baluns from Balun Designs. They are designed for 
250 W and cost about $50. Excellent design and construction.

http://www.balundesigns.com/low-power-qrp-baluns/ 
<http://www.balundesigns.com/low-power-qrp-baluns/>

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On May 26, 2016, at 6:04 PM, jso...@comcast.net wrote:
> 
> Hello,
> I'm contemplating buying the BL2 balun. 
> It would be connected to 450-ohm transmission-line, which would go to a 
> version of W1AB's "killer-antenna", sized for 20m on a 31' jackite-pole. 
> 
> A reviewer of the BL2, on eham five years ago, commented about heat and 
> signal-loss. 
> The heat and signal-loss concern me, not at the QRP-level but higher wattage. 
> I realize it is spec'd at 250 W but how hot does it get? 
> 
> I've looked for data about insertion-loss for the BL2 and came up short 
> there. 
> Hopefully someone has measured the insertion-loss and could share that data. 
> 
> The "elecraft BL2 assembly and operating manual" has the cores as ferrite 
> material. 
> But ferrites exhibit non-linear properties, so the loss may be a function, 
> not only of frequency, but also drive-level. 
> Insertion-loss shows up as heat and that heat affects the properties of the 
> ferrite. 
> 
> As I wrote above, I'm not concerned about QRP operation. 
> If I put it into operation on FD and but take my KX3 home for the day, what 
> happens if a club-member connects his 100+ W rig to the antenna-system to 
> operate thru the night? 
> TIA for any reply. 
> 
> 73 Jerry KM3K
> KX3 #6088
> __
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> This list hosted by: http://www.qsl.net Please help support this email 
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> wun...@wunderwood.org

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Re: [Elecraft] Balun BL2

2016-05-26 Thread Vic Rosenthal 4X6GP/K2VCO 
How hot it gets is determined by 1) the SWR and 2) the configuration of 
the antenna/feedline -- how much common mode power it has to dissipate.


I have a DX Engineering balun rated 5 kW continuous and 10 kW 
intermittent which /overheated/ on some bands when running 1 kW -- until 
I added capacitance or inductance on the antenna side of the balun to 
cancel out the reactance and at the same time detune the feedline for 
common mode current. Now it stays cold.


73,
Vic, 4X6GP/K2VCO
Rehovot, Israel
http://www.qsl.net/k2vco/

On 27 May 2016 04:04, jso...@comcast.net wrote:

Hello,
I'm contemplating buying the BL2 balun.
It would be connected to 450-ohm transmission-line, which would go to a version of W1AB's 
"killer-antenna", sized for 20m on a 31' jackite-pole.

A reviewer of the BL2, on eham five years ago, commented about heat and 
signal-loss.
The heat and signal-loss concern me, not at the QRP-level but higher wattage.
I realize it is spec'd at 250 W but how hot does it get?

I've looked for data about insertion-loss for the BL2 and came up short there.
Hopefully someone has measured the insertion-loss and could share that data.

The "elecraft BL2 assembly and operating manual" has the cores as ferrite 
material.
But ferrites exhibit non-linear properties, so the loss may be a function, not 
only of frequency, but also drive-level.
Insertion-loss shows up as heat and that heat affects the properties of the 
ferrite.

As I wrote above, I'm not concerned about QRP operation.
If I put it into operation on FD and but take my KX3 home for the day, what 
happens if a club-member connects his 100+ W rig to the antenna-system to 
operate thru the night?
TIA for any reply.

73 Jerry KM3K
KX3 #6088

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Re: [Elecraft] Balun BL2

2016-05-26 Thread Walter Underwood 
You might look at the “QRP” baluns from Balun Designs. They are designed for 
250 W and cost about $50. Excellent design and construction.

http://www.balundesigns.com/low-power-qrp-baluns/ 


wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On May 26, 2016, at 6:04 PM, jso...@comcast.net wrote:
> 
> Hello, 
> I'm contemplating buying the BL2 balun. 
> It would be connected to 450-ohm transmission-line, which would go to a 
> version of W1AB's "killer-antenna", sized for 20m on a 31' jackite-pole. 
> 
> A reviewer of the BL2, on eham five years ago, commented about heat and 
> signal-loss. 
> The heat and signal-loss concern me, not at the QRP-level but higher wattage. 
> I realize it is spec'd at 250 W but how hot does it get? 
> 
> I've looked for data about insertion-loss for the BL2 and came up short 
> there. 
> Hopefully someone has measured the insertion-loss and could share that data. 
> 
> The "elecraft BL2 assembly and operating manual" has the cores as ferrite 
> material. 
> But ferrites exhibit non-linear properties, so the loss may be a function, 
> not only of frequency, but also drive-level. 
> Insertion-loss shows up as heat and that heat affects the properties of the 
> ferrite. 
> 
> As I wrote above, I'm not concerned about QRP operation. 
> If I put it into operation on FD and but take my KX3 home for the day, what 
> happens if a club-member connects his 100+ W rig to the antenna-system to 
> operate thru the night? 
> TIA for any reply. 
> 
> 73 Jerry KM3K 
> KX3 #6088 
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to wun...@wunderwood.org

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[Elecraft] Balun BL2

2016-05-26 Thread Tony Marr 
Hi Jerry,

 

I've used the BL2 extensively, especially on my trips to E51. I've fed all
sorts of SWR-unknown antennas with it, running the pile-ups with my K3 at
100w.

 

On some antennas, it does get quite warm, but I keep it absolutely cool by
running a small 12V computer muffin fan alongside it, and the circulating
air stops it heating at all.

 

It's survived thousands of QSOs like this, and I also use it QRP here back
home in ZL, and have no problems with any apparent insertion loss. I don't
have any accurate way of measuring loss, but, personally, I don't see the
need to bother. I think it's a great little kit.

 

73,

 

Tony, ZL2AGY/E51AGY.



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[Elecraft] Balun BL2

2016-05-26 Thread jsodus 
Hello, 
I'm contemplating buying the BL2 balun. 
It would be connected to 450-ohm transmission-line, which would go to a version 
of W1AB's "killer-antenna", sized for 20m on a 31' jackite-pole. 

A reviewer of the BL2, on eham five years ago, commented about heat and 
signal-loss. 
The heat and signal-loss concern me, not at the QRP-level but higher wattage. 
I realize it is spec'd at 250 W but how hot does it get? 

I've looked for data about insertion-loss for the BL2 and came up short there. 
Hopefully someone has measured the insertion-loss and could share that data. 

The "elecraft BL2 assembly and operating manual" has the cores as ferrite 
material. 
But ferrites exhibit non-linear properties, so the loss may be a function, not 
only of frequency, but also drive-level. 
Insertion-loss shows up as heat and that heat affects the properties of the 
ferrite. 

As I wrote above, I'm not concerned about QRP operation. 
If I put it into operation on FD and but take my KX3 home for the day, what 
happens if a club-member connects his 100+ W rig to the antenna-system to 
operate thru the night? 
TIA for any reply. 

73 Jerry KM3K 
KX3 #6088 
__
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