[CQ-Contest] Stubs

[Joe]

That IS a good question.

Anyone have any typical plots?

I have read that use of a lossy line will lessen the depth of the notch, 
but it will also broaden it too. depending on operating practices a 
trade off?

maybe optimize them? since for the 40 meter stub, cut it first shorter 
say for 7225 KHz, 269.66 inches. with a like BNC connector on the end.

Then make up a short connector, that adds about 7 more inches to it to 
drag the null down to 7050 or so?

This also makes it possible to make a shorted connector too to short the 
ends when needed to make it the 20 meter null.

Joe WB9SBD
Sig
The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com
On 5/6/2013 9:55 PM, Charles Harpole wrote:
> Further question..... with a correctly made stub, what is its band of
> protection?  50kc from the design frequency or 100kc or more still provides
> null protection?????????
> Charly
>
>
> On Mon, May 6, 2013 at 7:49 PM, Joe <nss at mwt.net> wrote:
>
>> Getting ready for Field Day here.
>>
>> The only bands we seem to have problem on are 40 & 20 with the two
>> stations hearing each other.
>>
>> So plan on making up a pair of stubs, for each station.
>>
>> Now from wat i have found seems pretty simple.  and will this actually be
>> correct?
>>
>> It looks like the 1/4 wave (electrical) on 40 un shorted will block 0 an
>> pass 20  yes?
>>
>> and the exact same stub shorted will pass 40 and block 20  yes?
>>
>> so adding at the far end a small SPST toggle switch should make a easy
>> switch 20 or 40 stub  yes?
>>
>> Now I plan on using them in the usual manner right at the rigs with a "T"
>> connector.
>>
>> To make them we plan on using a MFJ 259B
>>
>> The way they say to make a stub using it is pretty plain and straight
>> forward and easy, "BUT"........
>>
>> I'm assuming I should include the "T" when making the stub to have it
>> include the extra length it is making.
>>
>> Now what do I do with the open end of the "T"?
>>
>> does it need to me terminated? like with a 50 ohm dummy load? o9r left
>> open is ok, or what?
>>
>> Anyone?
>>
>> Joe WB9SBD
>>
>> For Field Day The Yellow Thunder Amateur Radio Club
>> WB9FDZ
>> The field Day Zombies
>>
>> --
>> Sig
>> The Original Rolling Ball Clock
>> Idle Tyme
>> Idle-Tyme.com
>> http://www.idle-tyme.com
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>
>