You don't need an UNUN with the system. Connect the 1/2" CATV 75 ohm
hard line to the feed point on the antenna, and use a short jumper of
RG8X or RG6 between the hard line to the radio for convenience.
73
Bob, K4TAX
On 3/31/2020 1:06 PM, [email protected] wrote:
The 200' run is Cable TV hardline (1/2") 75 Ohm, that's where the UnUn would go
(maybe).
Jerry Moore
Cell: 803-431-1870
-----Original Message-----
From: Victor Rosenthal 4X6GP <[email protected]>
Sent: Tuesday, March 31, 2020 1:58 PM
To: [email protected]; [email protected]
Subject: Re: [Elecraft] 75ohm Impedance question K3S and Antenna side.
I don't think you need a unun because the additional loss due to SWR running
RG/6 at 2:1 is only 0.381 dB, and the unun itself would certainly have some
loss.
But the loss in 200' of RG/6 even at 1:1 is about 2.9 dB! That is almost half
your power. RG/8 would have only 1.9 dB loss, and with a probable SWR of about
1.5:1 you would have a total loss of 2.2 dB.
Even better would be Belden 9913 or similar coax, which would give you a total
loss of 1.6 dB.
All these facts and more are available at
<https://www.qsl.net/co8tw/Coax_Calculator.htm>
73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
CWops no. 5
http://www.qsl.net/k2vco/
On 31/03/2020 19:39, [email protected] wrote:
I'm about to pull the trigger on a Hustler 6BTV (6-Band, 80, 40, 30,
20, 15,
10 meters). It will be temporarily installed (with radials) about 200'
away from my house. I'd like to run CATV "hardline" but I'm not sure
how to get a
2:1 UnUn with a wide enough bandwidth on the antenna side (the
impedance with 60ish radials should be in the 35ohm range). In
addition I believe I will be ok on the RIG side to just connect RG6
(75ohm) to the hardline and direct to the rig since my K3S can match
the impedance. Is this essentially correct and is there a better way
to do this? I'm trying to minimize losses for the distance run and still have a
decent transmitted signal.
Thanks in advance.
Yeah, I should know this stuff but I can't know everything 100%.
73 es
De AE4PB
..
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