I am not sure what type of filtering that the 7300 has, but it was interesting to read that his K3 as well as Flexradio did not have this problem. I just wonder how many people are looking at purchasing a 7300 for a possible SO2R scenario? It should be interesting to see how many other comments come out regarding the 7300 with this issue.
Mark Griffin, KB3Z
My latest non-SDR is a 30+ yr old Kenwood ts-530sp. It saw several field days in close proximity to multiple other radios. Even though it was 30 or so years ago I do not recall any overloaded front ends or being unable to participate in FD because golly gee, one can't do field day without SDR, which hadn't been invented yet.
Where SDR is so prevalent in cell phones, how is it two people standing next to each other can be on their cell phones at the same time? Yes, I understand they are on different frequencies, so are two people at FD.
I remember one field day a person throwing his head phones down because of proximity too close to same frequency.
They had to seperate farther on the 20 meter band as not to interfere with each other.
Antenna spacing in the field I think has alot to do with it.
Good planned field day on antennas helps. ( not wires crossed lol)
I know Flexradio on field day we experimented with TX/RX and had another radio on the same band and the flex would wipe his RX frontend out but not the other way around. The flexradio rx from the other station would show up in the panadapter like any other signal and dial it in and listen.
There is a youtube video about the 7300 overload issue.
I used an IC-745 in a multi transmitter field day site and it suffered a bit, depending upon the band.
My TS-850 was a lot better, but limited by the phase noise of the other transmitters, and some overload if I didn't turn off preamps, and sometimes add some attenuation.
I won't be at field day this year. But it would be interesting to try the 6500 some year. But I am hesitant to let it out of my sight! It is one thing to have an old rig worth $800 messed up. It is another thing to risk almost $5000 in a tent at field day.
'Sherwood notes: "With IP+ OFF, intermodulation degrades gracefully. Recommend only using IP+ when absolutely necessary due to noise floor degradation."'
That's an important point. The 7300 could (and perhaps should) be listed twice even though dual figures are shown in the 2 kHz DR column. Although it would be painful to see on a chart, the 7300 is probably more accurately shown in between the TS-830, Atlas 350 and IC-703+. Why? Because the IC-7300's normal operation is with IP+ deactivated and that causes a severe hit in its placement in the 2 kHz DR column.
Although the cause for the change in DR is vastly different in the IC-7300 with IP+ active, it's really no different than ranking a traditional superhet by activating its front end attenuator. Again, the root cause is different with IP+ since dithering is added rather than hard attenuation, but both examples lead to very deceiving results when ranked on a chart.
Of course, it's Rob Sherwood's prerogative as to how he ranks receiver performance, but when the IC-7300's normal operation is with IP+ deactivated, it seems to me the more appropriate narrow-space DR ranking is next to the Kenwood TS-830.