Topband: Topband Inv-L Joy

[Shoppa, Tim]

I myself, tune my 160 antenna with a simple L-matching network at the base. I used EZNEC to model the antenna, and an online L-network calculator, and it was spot-on. I was very impressed. Since you can measure the antenna right at the base with your antenna analyzer, you can do even better. Your match is almost perfect already, it should only take a moderate matching network.

You must have a really long coax run if you are getting so much loss with such a close match already.

For DX'ing, a better target frequency is probably 1820kc rather than 1802kc, but with a moderate matching network you'll get low SWR for many 10's of kHz around either side of the center freq.

Online L-network calculator I used: http://home.sandiego.edu/~ekim/e194rfs01/jwmatcher/matcher2.html

Tim N3QE

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Gary Smith
Sent: Thursday, July 25, 2013 1:22 AM
To: topband at contesting.com
Subject: Re: Topband: Topband Inv-L Joy

Had a more difficult time getting the antenna up there this time. The first spud snapped away from the fishing line & in the dense thicket I was unable to find where it landed. Had to make another & the mosquitos were so thick they posted a LUAU sign on my forehead.

Till I get something better I retrieved my WD-1A military field phone wire that was left out in the marsh as my old beverage wire. and after a comedy of errors I finally got the antenna up. 

I was earlier getting a SWR of 1.1 on 160 before and now am getting
1.1 on 1.74365 MHZ

1.74365mhz
R=51 X= 6,7,8
swr 1.1

At the desired frequency to match the antenna I've aimed for 1.8MHZ here's the information I was able to get at my desired frequency:
1.8025 mhZ
Coax loss 6.3db
C=4193  XC=21      
L=1.970  X1=21
r=41 x=21 swr 1.6

So this is what the antenna is giving me at this moment. I need to get back down and add the broken wire to the radial bed and I should also trim some length to bring my values to 1.1 at 1.025MHz. 

Given the info above from the MFJ 259B any idea how much I might nibble off and more, is there anything in this info that tells me I should look to do anything differently?

Hopefully the coax loss will be mitigated by a friend bringing me 350' of hardline. Can't wait!

Thanks,

Gary
KA1J
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Topband Reflector