Topband: Nested Loops with one feedline results

[Charlie Cunningham]

H I, Herb

Well, I expect that your 80/160 delta loop can be made to play well. Do you
use EZNEC?  It's  heck of a lot easier to deal with the interactions with a
keyboard and mouse than raising and lowering and pruning the loops!  :-)

73,
Charlie, K4OTV

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Herb
Schoenbohm
Sent: Monday, September 02, 2013 7:09 PM
To: topband at contesting.com
Subject: Re: Topband: Nested Loops with one feedline results

Thanks Rick,  I presume a true quad loop would bring different results with
a common feed.  I have heard of a single feedline working well with a 5 band
quad so I presume that a triangular "Delta Loop" has a completely different
relationship?

Herb, KV4FZ




On 9/2/2013 6:34 PM, Richard (Rick) Karlquist wrote:
> The 18/24 is not a good analogy, because those bands are not octave 
> spaced.  My modelling indicated that you need to open up the lower 
> frequency antenna at two places, 180 degrees opposed, in order for it 
> not to affect the higher frequency antenna.  Also, the openings should 
> be such that the remaining wires are cross polarized to the higher 
> frequency antenna.
>
> Rick N6RK
>
> On 9/2/2013 3:09 PM, Herb Schoenbohm wrote:
>> Several replies to my inquiry on having a closed 80 meter inverted 
>> delta loop inside a 160 meter delta loop brought me some nice 
>> replies.  So I decided to build one for 18Mhz and 24Mhz with the feed 
>> going to the outside Delta loop hoping this would properly allow dual 
>> band operation with a single feed.  The inside 24 Mhz delta was 
>> closed and hung inside a the fed 18 Mhz antenna.  The results showed 
>> that it had no impact on the
>> 18 Mhz antenna but the VSWR on 24.9 was unusable.  Then I decided to 
>> open the 24 Mhz Delta and connect the two wires to the 18 Mhz feed 
>> and now have both bands working with a VSRW below 1:2 to 1 on either
band.
>> The feed-line for the antenna is RG-213 with a 1/4 wave piece of 
>> RG-11 cut for 18 Mhz.  I am surprised that the 1/4 wave matching 
>> piece did not seem to impact the antenna on 24.9 at all.
>>
>> I will now proceed to build an 80 meter full wave delta inside my 160 
>> meter one and rely on the simulation on 18/24 Mhz to get a good 
>> match. I trust it will work although the ground proximity might have 
>> some impact on everything.
>>
>>
>> Thanks for the replies on this.
>>
>>
>> Herb Schoenbohm, KV4FZ
>> _________________
>> Topband Reflector
>>
>>
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> Topband Reflector

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