Icom IC-7300 MW/LW/VLF performance

[zoofer]

After nearly 20 years of use as a mobile and shack transceiver, my IC-706MkIIG is ready for a well deserved retirement. Since I spend more time monitoring frequencies below 500 KHz using my SDRs than I do transmitting, I want my next amateur transceiver to have good receive performance in the BCB/LW/VLF range as well. I see the IC-7300 tunes down to 30 KHz, but I haven't been able to find any online reviews or YouTube videos specific to those frequencies.

Anyone here have any experience using the 7300 for DXing the BCB or monitoring frequencies below 500 khz, especially the VLF range? Specifically interested in potential MW overload issues as I have one local AM station that plays havoc with my CCrane CCRadio2 but doesn't affect my other receivers.

Would also be interested in experiences with other amateur transceivers that have good receive performance in that range.

Thanks & 73.
Kevin, W0VP

 

[KB4MSZ]

I know a number of HF transceivers can "tune" to lower KHz frequencies as far as what they display on the dial but actually having any reasonable performance that low can be another matter. My Yaesu FT-891 also tunes down to 30 KHz, but it doesn't appear to hear anything down there. I tested this side by side one night with my SDRPlay RSPdx receiver. The RSPdx hears the WWVB signal at 60 KHz very well, sometimes over S9 (as well as some long wave beacons) but the 891 heard absolutely nothing with the same antenna. In fact, the 891 had no real noise floor like the RSPdx has, just a quiet smooth hiss. I guess that type of operation just isn't what the 891 was designed for. Maybe the 7300 might do better.

 

[ka3jjz]

I don't have either radio (boy do I wish that I did), but in the old days, it was very common for radios to reduce sensitivity below a certain point to prevent mixing products and overloading appearing in the long wave and some parts of the medium wave band. Given that we now have allocations in LW as hams, I would put serious money on someone finding out how to defeat this attenuation (if it does indeed exist).

Also keep in mind that there is no North American broadcasting on LW; therefore there's no incentive to design a good front end for these ranges (at least for the North American models).

Mike

 

[zoofer]

It appears that I'm not likely to find an amateur transceiver (in the price range i am working with anyway) with the receive performance at frequencies below 500 kHz that I have become used to with my SDRs. I will simply switch to plan B and use a VLF downconverter for those frequencies - Palomar Labs or something similar. But thanks for the responses! 73 de W0VP.

 

[N9PBD]

Hi @zoofer, I owned a IC-7300 for couple years, traded up to an IC-7610. I used my 7300 to hunt for low band beacons (NDB, etc.), with great success. The low noise receiver, coupled with the excellent display helps you find weak signals that would otherwise be missed. My 7610 shares the great LW/VLF receiver performance with the 7300, so I continue my hunting (well, at least until the summer noise drowns a lot of them out).