Topband: Rohn 25 Vertical questions.

[fmoeves]

Gorge, What is the  rx 4 direction delta loop you mentioned below. Thanks Fred KB4QZH 
-------- Original message --------From: GEORGE WALLNER <aa7jv at atlanticbb.net> Date: 8/21/20  3:30 PM  (GMT-05:00) To: "Richard (Rick) Karlquist" <richard at karlquist.com>, donovanf at erols.com, Ron WV4P <wv4ptn at gmail.com> Cc: 160 <topband at contesting.com>, Mail 10 <mail10 at barefoothorse.com.au> Subject: Re: Topband: Rohn 25 Vertical questions. At C6AGU I have in-band RX on all bands. The rigs are Flex 6000 SDR-s. On 160 m I can hear virtually unimpaired to about 12 kHz off the TX frequency. RX antenna is 4 direction delta loop, about 1000' from the TX vertical. The RX path includes a high performance RX pre-amp. (The RX antenna "gain" is -32 dBi.)SDR-s can work for in-band RX, but you must have a very "clean" RX (and TX) paths and plenty of antenna separation. Also, lots of shielding and grounding.73,George,AA7JV/C6AGUOn Thu, 20 Aug 2020 15:17:29 -0700  "Richard (Rick) Karlquist" <richard at karlquist.com> wrote:>>> On 8/19/2020 10:28 PM, donovanf at erols.com wrote:>> Hi Ron,>>>>>> 700-1200 foot spacing should provide good in-band receiving capability.>> SDR receivers won't work for in-band receive, you must use a traditional>> transceiver such as the K3, K4HD, FTdx5000, IC-7800 etc.>>>>>> Micro-arcing is caused by transmitted RF jumping a spark gap.>> Any metal-to-metal joint that isn't securely bonded is a candidate>> for micro-arcing.>>>>>> 73>> Frank>> W3LPL>>> Three questions:>> 1.  Does "in-band receiving" mean the same thing as SO2R in a single> band contest?  I operated a few 160 meter contests in that mode around> 10 years ago.  I used a carefully nulled receiving loop 1000 ft from the> TX vertical.>> 2.  Please explain the comment about SDR receivers not working.  I> now have a Flex 6700 that claims to be able to do full duplex.  And> that radio would not work?>> 3.  If connections between R25 sections cannot be trusted, then> how would any crank up tower possibly work as a vertical?  I have> always wondered about this.>> BTW, cellular sites have significant problems with what they> call "passive IMD", of which micro-arcing is a subset.>> 73> Rick N6RK> _________________> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector_________________Searchable Archives: http://www.contesting.com/_topband - Topband Reflector