[CQ-Contest] Busted Reversed Beacon Network spots

Igor Sokolov ua9cdc at gmail.com
Mon Jun 10 08:19:51 EDT 2013

Hi Yan,
59+50 signals are not very common in contests although such signals can 
sometimes be ran into. Having said that, I would avoid parking only 2 Khz 
away from such a signal in the  contest because they usually are pretty 
clicky as well. For the record, we have remote antenna, which is 300 m away 
from the main antennas. That allows us to listen on the same band where the 
main signal is. At 1 Kw output the main signal on the second receiver is 
just about 59+50. The isolation between antennas is about 80 db (side by 
KX3 also has a provision for setting IF at 8Khz which can sometimes be 
pretty helpful.

73, Igor UA9CDC
----- Original Message ----- 
From: "XV4Y" <xv4y at nature-mekong.com>
To: <CQ-Contest at contesting.com>
Sent: Monday, June 10, 2013 7:38 AM
Subject: Re: [CQ-Contest] Busted Reversed Beacon Network spots

>> Bret, before you attack SDR receiver performance indiscriminately, take
>> a look at Rob Sherwood's review of the KX3.
> Hi Pete,
> You are right about the KX3.
> In its detailed report, Rob NC0B specifically comments that despite its 
> good close DR3 the KX3 will perform badly in a contest environment.
> The "digital conversion IF" is only in the vicinity of 1 KHz and image 
> rejection is very low (around 70dB).
> The KX3 will not suffer from having its AGC pumping because of strong 
> adjacent signal, nor it will suffer from RMDR, but just from phantom 
> signals coming from the opposite band.
> If you have a S9+50dB at, let's say 2 KHz below (not uncommon in a 
> contest), it will appear around S7 in your receiver, loud and clear.
> Rob Sherwood table classification only use one index for ranking and it is 
> the DR3 at 2 KHz on 20m with preamp off and using a 500 Hz filter.
> It was meant to compare transceiver of the 90's that were using 
> up-conversion circuits and thus having very good sideband and image 
> rejection numbers.
> The KX3 is a wonderful SOTA and portable radio; not designed to be a 
> contest or DXpedition radio.
> 73,
> Yan.
> ---
> Yannick DEVOS - XV4Y
> New online shop for kits and more
> http://xv4y.radioclub.asia/boutique/
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