[Elecraft] Field Day rig experience

[WILLIE BABER]

More then one so2r operator has noted that the 7300 will overload in an so2r situation so that you cannot clearly hear on 7300 when the other radio is transmitting (yes, on a different band).  Since the 7610 doesn't have a front-end either, I imagine that it will do the same.  Sherwood himself notes that using the SDR radio (i.e, without a superhet front-end) means reducing gain to limit ADC overload, but he has also suggested that blocking dynamic range is over-rated.  Generally this is true, dynamic range is over-rated if you are using one radio.  However, blocking isn't over-rated in a field day situation (more than one radio) or if you have a neighboring op running high power, or in legal-limit multi-op situations (with antennas relatively close to each other), or in legal-limit so2r.

Reducing sensitivity works to prevent ADC overload on the lower bands where sensitivity is not needed in the first place but on 15m through 6m one can use the sensitivity.  While SDR radios have their advantages, some of the advantages of superhet radios still exist today, namely, that a so-called roofing filter front-end (which is just a mode-specific filter ahead of the first mixer) will deliver outstanding blocking AND as much sensitivity as required (compared to SDR).

I don't see any way around this fact (at least not yet) and you can see the difference in the Sherwood numbers.

73, Will, wj9b

CWops #1085
CWA Advisor levels II and III
http://cwops.org/

--------------------------------------------
On Sat, 6/9/18, Wayne Burdick <n6kr at elecraft.com> wrote:

 Subject: Re: [Elecraft] Field Day rig experience
 To: "Bill" <billclarke at nycap.rr.com>
 Cc: "Elecraft Reflector" <elecraft at mailman.qth.net>
 Date: Saturday, June 9, 2018, 10:34 AM
 
 
 > On Jun 9,
 2018, at 5:24 AM, Bill <billclarke at nycap.rr.com>
 wrote:
 > 
 > Along the
 line (lightly discussed under "K3- AF Knob") of
 what rigs are used for dxpeditions and Field Day......  How
 do the new technology ICOMs (7300 and 7610) do under the
 "several rigs on the same band" conditions? The
 size, weight, and cost factor is inviting for the 7300 -
 BUT!!! Is it up to the job? Close to up to the job? Or,
 better left home during these events?
 
 
 Hi Bill,
 
 Hopefully you’ll get some responses to this
 question from those with direct experience. But looking at
 it theoretically: both the 7300 and 7610 are direct-sampling
 radios with about 25-30 dB less blocking dynamic range than
 the K3 or K3S. On Field Day this could have a definite
 impact when using multiple transmitters on the same band, or
 even on different bands, depending on antenna spacing and
 power level used. 
 
 Dynamic
 range of all of these radios is quantified in the receiver
 performance table at www.sherweng.com, specifically the
 fifth column (“100 kHz Blocking”).
 
 Wayne
 
 
 
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