Hi Grant.
Tnx for the info. Putting up a DHDL like at H40TT is on my list. I want to
install another BOG first for a comparison to my 3-el W1FV and two dual feed
Pennants. I miss my 625' beverage I had in Joisey. I don't have the room here.
N2tK, Tony
-----Original Message-----
From: Grant Saviers <grants2@pacbell.net>
Sent: Sunday, December 8, 2019 11:56 AM
To: tony.kaz@verizon.net; topband@contesting.com
Subject: Re: Topband: 12V through coax
For my relay reversible DHDL's used on 160 & 80m, I'm using 0.1uf 500v DC
blocking capacitors, particularly the Kemet X7R MLCC SMD ones.
digikey 399-6747-1-nd There are enough parts for reversibility that I designed
a small PCB with ExpressPCB so SMD parts made sense.
The RFC inductor choice depends on the current draw, for my design, all in was
92ma so a ferrite core design with a saturation current (10% reduction in L) of
120ma was ok at 450uH and an SRF of 4.5MHz. From Wurth, SMD again. digikey
732-10766-1-ND
Automotive grade thick film 1/2 and 1w SMD resistors have very high surge
ratings so are what I used for terminators. If you have some old A-B carbon
ones in your stash, they are a good choice.
These parts worked well at H40TT on two DHDLs and we had some T-storms nearby
without damage.
Grant KZ1W
On 12/7/2019 20:59, tony.kaz--- via Topband wrote:
> I am making up new boxes for my Pennants. I will be switching
> directions with a relay in the box besides the terminating resistor and the
> choke.
> My question is what are the correct values of the components for
> feeding the 12V? I will be using this only on 160 and 80M.
> For the coupling cap between the rig and antenna I have seen values
> from .01-.1uf. For the choke I have seen values from 100 uhy - 4.7 mh.
> On the 12V feed side I have seen values from .01 - .1 ufd.
> Is there a rule of thumb for the range of correct values for 80 and 160M?
> Thanks
> N2TK, Tony
>
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