[TowerTalk] Finding resonant frequency in tuned circuits with MFJ-259 ???

[Douglas Ruz (CO8DM)]

Hi everybody !!!,

I build a coax trap for 80m...12 turns of RG59 in 75mm diameter PVC.

I have been checking the resonant frequency with my old MFJ-259 ant 
analyzer...the MFJ manual said:

"A second method of determining the resonant frequency is by using a small 
three or four link
coil to magnetically couple to a tuned circuit for testing. The coil should 
be wound around the
inductor in the tuned circuit. This magnetically couples the MFJ-259 to the 
resonant circuit.
The frequency of the MFJ-259 is adjusted for a dip on the "SWR" meter. The 
dip occurs at

the approximate resonant frequency of the tuned circuit."

I did it like the manual but does not work...i tried with 3 and with 4 turns 
but nothing...then i tried with only "HALF TURN" and i found the dip on 3701 
Khz

I do not understand what happen...i built the link coil with 22 AWG 
insulated cable.

any idea?

Thanks,

73....Douglas, CO8DM

"No creo que haya alguna emoción más intensa para un inventor que ver alguna 
de sus creaciones funcionando. Esa emoción hace que uno se olvide de comer, 
de dormir, de todo." - Nikola Tesla
----- Original Message ----- 
From: "N2TK, Tony" <tony.kaz at verizon.net>
To: <TowerTalk at contesting.com>
Sent: Thursday, October 15, 2015 8:36 AM
Subject: Re: [TowerTalk] SteppIR DB36/42 80m option


> Hi Eric,
>
> The dipole radiates at right angles to the boom. The end elements are for
> loading. My MonstIR is at 83'. I also have an elevated wire 4-sq for 80M.
>
> I live in upper NY state. From my QTH here is what I typically see:
>
> For US, Canada and the Caribbean the MonstIR dipole is better.
>
> To western EU, and Central America it swings back and forth which is 
> better.
> On the longer haul stuff the 4-sq is always better. This is what I would
> expect.
>
>
>
> Tough trying to compare with your neighbor. Compare HFTA plots. There
> shouldn't be too much difference between a 2-el and 3-el on 40M if the
> heights and terrain are similar.
>
>
>
> When I had my 80M 4-sq wires pulled in close to the top of the tower I
> noticed interaction between the MonstIR and 4-sq. Took 'LPL's suggestion 
> and
> made the 4-sq into inverted L's to get the wires farther away from the
> tower. This helped F/B on the 4-sq. This also  seemed to reduce 
> interaction.
> And 40M SWR on the MonstIR would change from lowering and raising the 80M
> 4-sq wires until I pulled them away from the tower.
>
>
>
> 73,
>
> N2TK, Tony
>
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of 
> K2CB
> Sent: Wednesday, October 14, 2015 9:20 PM
> To: TowerTalk at contesting.com
> Subject: [TowerTalk] SteppIR DB36/42 80m option
>
>
>
>
>
> While we are discussing 80m antennas, can someone shed some light on the
> radiation pattern of the SteppIR dipole option for the larger DB36 and 
> DB42
> models?
>
>
>
> Is the maximum radiation towards the front and back of the antenna 
> elements,
> or off the left and right sides of the boom?
>
>
>
> Also, what would you consider this design? Some sort of "H" dipole?
>
>
>
> Anyone know of any good write ups on this sort of "H" antenna design (the
> 80m portion, obviously) on the web?
>
>
>
> Finally, has anyone compared this to an 80m inverted V at similar heights?
>
>
>
> I have the DB36 with the dipole option at 91 ft, and an inverted V 80m
> dipole with the feed point/ apex just below it at 89 feet. The end of the
> two legs of the inverted v are at approximately 45ft above ground.
>
>
>
> I also have legs for 160m fed off the same feed point, which sit/hang 2 or 
> 3
> feet above the 80m legs.  They are tied to the same end posts as the 80m
> legs. I just leave the ropes for the 80 m legs a little bit looser so they
> sag down below the 160 m legs by a few feet on the way down from the 
> tower.
> Unfortunately I have no trees on the property, so the only tie offs are 
> two
> posts in the far corners of my property.
>
>
>
> I am sure there is some severe interaction, so it really is hard for me to
> tell which one works better sometimes.
>
>
>
> My experience with both seems to show that the StrppIR "H" dipole is a
> little better for the long haul stuff into Europe, while the inverted V is
> much better (by 10db) for the close in (200-300 mile) and rag chew type
> contacts on 80 m.
>
>
>
> On a related note, I believe I am having some noticeable interaction with
> these inverted V's when I have the SteppIR on 40 m. As a non-scientific
> comparison, my buddy (N2II) up the road a few miles with only a two 
> element
> 24ft boom linear loaded 40m yagi at the same 89ft height seems to do 
> equally
> as good, if not slightly better, as I do with the three element 36ft boom
> SteppIR on 40 m.
>
>
>
> I have no experience with modeling, unfortunately. My area of expertise in
> the hobby is radio and amplifier repair. FWIW, I am willing to trade 
> repair
> services for modeling services if anyone is ever interested in modeling my
> antenna set up.
>
>
>
> Eric
>
> K2CB
>
>
>
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