Topband: Hi Z amplifiers for 160m
GEORGE WALLNER
aa7jv at atlanticbb.net
Wed Mar 11 09:28:44 EDT 2020
Chris,
Assuming a trans-impedance amplifier, "unity gain" is enough (with
reasonable size elements). Noise and IP3 are far more important. Lightning
and surge immunity are also important. Also, isolate the amp from common
mode noise travelling on the feed-line. Filter the power supply well. Use an
F connector (a high quality one that can be torqued.)
GL and 73,
George,
AA7JV/C6AGU
On Wed, 11 Mar 2020 11:33:34 +0000
Chris Moulding <chrism at crosscountrywireless.net> wrote:
> As well as being a radio amateur (G4HYG) I also run a small business designing and making radio equipment (Cross Country Wireless).
>
> Recently I've been asked by a radio contest group to see if I can redesign the YCCC Hi Z amplifier using modern components and using similar mounting arrangements to our Loop Antenna Amplifier.
>
> The first prototype using surface mount components is working well.
>
> So far I've not build an array of antennas but that will come later when the production boards arrive.
>
> The prototype uses a unity voltage gain amplifier and a BNC connector.
>
> I've a couple of questions for others on the list with experience of running vertical receive arrays:
>
> Is a unity voltage gain amplifier OK or do you think it needs more gain for long coax runs?
>
> At present I'm using a BNC male connector for the output. Would an F type connector be more compatible with existing antenna arrays.
>
> 73, Chris G4HYG
>
> _________________
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