Tag Archives: comparison

Comparing the Icom IC-705 and Icom IC-7300 with the Xiegu GSOC G90 combo

I was recently asked to make a table comparing the basic features and specifications of the new Xiegu GSOC/G90 combo, and comparing it with the Icom IC-7300 and IC-705.

This is by no means a comprehensive list, and I plan to add to it as I test the GSOC. It doesn’t include some of the digital mode encoding/decoding features yet. I’m currently waiting for the next GSOC firmware upgrade (scheduled for November 20, 2020) before I proceed as it should add mode decoding, audio recording, fix CW mode latency, and add/fix a number of other items/issues.

Comparison table

Click to enlarge

Quick summary of comparison

At the end of the day, these radios are quite different from each other. Here’s a quick list of obvious pros and cons with this comparison in mind:

Xiegu GSOC G90 combo ($975 US)

Pros:

The GSOC’s 7″ capacitive touch screen is the biggest of the bunch
The GSOC can be paired with the G90 or X5101 transceivers (see cons)
The GSOC controller is connected to the transceiver body via a cable, thus giving more options to mount/display in the shack
The G90 transceiver (read review) is a good value and solid basic transceiver
Upgradability over time (pro) though incomplete at time of posting (con)
GSOC can be detached, left at home, and G90 control head replaced on G90 body to keep field kit more simple (see con)

Cons:

The GSCO is not stand-alone and must be paired with a Xiegu transceiver like the Xiegu G90 or X5105. The X5105 currently has has limited functionality with the GSOC but I understand this is being addressed. (see pro)
I don’t believe the GSOC can act as a sound card interface if directly connected with a computer (I will correct this if I discover otherwise). This means, for digital modes, you may still require an external sound card interface
No six meter coverage like the IC-7300 and IC-705
Quite a lot of needed cables and connections if operating multiple modes; both GSOC and G90 require separate power connections
At time of posting, a number of announced features missing in early units, but this should be addressed with a Nov 20, 2020 firmware upgrade
Replacing and removing G90 control head requires replacing four screws to hold in side panels and secure head to transceiver body (see pro)

Icom IC-7300 ($1040 US)

Pros:

Built-in sound card interface for for easy digital mode operation
Excellent receiver specifications (click here to view via Rob Sherwood’s table)
Possibly the most popular transceiver Icom has ever made (thus a massive user base)
Well thought-through ergonomics
Includes six meter operation and expanded RX frequencies (compared with G90/GSOC); high frequency stability

Cons:

The heaviest of this group (con), but it is a 100 watt transceiver (pro)
Smaller display than the GSOC
Touch sensitive display (not capacitive like the GSOC)
Faceplate not detachable like the G90

Icom IC-705 ($1300 US)

Pros:

Built-in sound card interface for for easy digital mode operation
Excellent receiver specifications (click here to view via Rob Sherwood’s table)
Can use swappable Icom HT battery packs
Well thought-through ergonomics, but on that of the IC-7300
Includes six meters and VHF/UHF multi-mode operation with high frequency stability
Includes D-Star mode
Includes wireless LAN, Bluetooth, and built-in GPS
Weighs 2.4 lbs/1.1 kg (lightest and most portable of the bunch)

Cons:

No internal ATU option
Maximum of 10 watts of output power
The priciest of this bunch at $1300 US

In short, I’d advise those looking for a 100 watt radio, to grab the Icom IC-7300 without hesitation. It’s a solid choice.

If you’re looking for the most portable of these options, are okay with 10 watts of maximum output power, and don’t mind dropping $1300 on a transceiver, the Icom IC-705 is for you. You might also consider the Elecraft KX3, Elecraft KX2, and lab599 Discovery TX-500 as field-portable radios. None of them, however, sport the IC-705 display, nor do they have native VHF/UHF multimode operation (although there is a limited KX3 2M option). The IC-705 is the only HF QRP radio at present that also has LAN, Bluetooth, and built-in GPS. And, oh yes, even D-star.

If you’re a fan of the Xiegu G90 or already own one, give the GSOC controller some consideration. It offers a more “modular” package than any of the transceivers mentioned above in that the controller and G90 faceplace can be swapped on the G90 body. The GSOC screen is also a pleasure since there are two USB ports that can connect a mouse and keyboard (driver for mine were instantly recognized by the OS). The GSOC/G90 combo is a bit “awkward” in that a number of cables and connections are needed when configured to operate both SSB and CW: a CW key cable, Microphone cable, I/Q cable, serial control cable, power cable for the GSOC, and a power cable for the G90. This doesn’t include the cables that might be needed for digital operation. I dislike the fact that the CW cable can only be plugged into the transceiver body instead of the GSOC controller like the microphone. Still: this controller adds functionality to the G90 (including FM mode eventually) that may be worth the investment for some.

Did I miss something?

I’ll update this list with any obvious pros/cons I may have missed–please feel free to comment if you see a glaring omission! Again, these notes are made with a comparison of these three models in mind, not a comprehensive review of each. I hope this might help others make a purchase decision.

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Results: AirSpy HF+ vs Elad FDM-S2 Weak Signal Comparisions

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Looking north toward Cape Lookout, Oregon, near the site of my SDR receiver recordings. Photo courtesy of Wikimedia Commons.
In my original article 10 days ago, I set up a SWLing Post reader poll to let you give your opinion on which shortwave recordings within four pairs of audio files provided the most intelligible result. The recordings were intentionally noisy, low-level signals to help us discover–through critical listening to the files–if there is a clear favorite between the AirSpy HF+ or the Elad FDM-S2 receivers. Of course, there were only four pairs of recordings…not a very large sample size.

However, 34 readers of the original article took the time to listen and respond, so let’s get to the numbers, shown in these graphs:

Interestingly, the responses above seem to point to:

Two recording pairs tied in the results (50% / 50%) or were very close (HF+ 52.9% / FDM-S2 47.1%)
The FDM-S2 led one recording pair by a large margin (67.6% / 32.4%)
The HF+ led another recording pair by an equally large margin (67.6% / 32.4%)

Taken as a whole, no obvious winner emerged, although one might conclude the HF+ has a slight edge due to its lead in the “very close” recording pair of 7.230 MHz.

One thing is clear–the AirSpy HF+ is a surprisingly good performer for its price of $199 USD! For many enthusiasts this will be all the SDR they need.

As a final note, I’ll mention that the AirSpy HF+ used for the tests was totally stock. I have not yet performed the “R3 Bypass” mod nor the firmware update to my HF+ units. The simple R3 Bypass, discussed at length on the AirSpy Groups.io forum, significantly boosts sensitivity of the HF+ from longwave up to about 15 MHz, without any noted overload issues. For more on this modification from a MW DXer’s perspective, read Bjarne Mjelde’s insightful article at his Arctic DX Blog.

Thank you to all the readers who took the time to listen to the SDR recordings in this comparision and register your opinions.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington. He’s a regular contributor to the SWLing Post.

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Digging in the Noise: Weak Signal Audio Recovery with the AirSpy HF+ and Elad FDM-S2

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I’m currently spending the better part of a week at Cape Lookout State Park on the Oregon coast, with a great view of the ocean through tall evergreen trees. This is one of my favorite parks in the Pacific Northwest, especially when DXing during the blustery winters from one of the nice cabins at Cape Lookout.

The view from the beach near my cabin; the turbulent waves were a precursor to the gale force winds at the park during the night of the 23rd!

Although I’m at the park for trans-Pacific medium wave DXing, I’m also comparing receivers, both SDRs and portables. This morning I sought out a few weak shortwave signals, pitting the Elad FDM-S2 SDR ($529 USD) against the AirSpy HF+ ($199 USD). I have a pair of the HF+ receivers to cover all of medium wave (as the FDM-S2 easily does). Many SWLing Post readers already know that the upstart HF+ trades bandwidth to gain high performance in order to keep the price reasonable.

My antenna used for the following recordings was a small “Flag” antenna using a Wellbrook Communications FLG100LN module and a 2K ohm variable potentiometer for termination. The design uses crossed tent poles in an “X” formation to support the wire loop. This design travels easily in a compact package; I have Dave Aichelman of Grants Pass, Oregon to thank for this very useful “tent pole loop” implementation of the Wellbrook FLG100LN.

The Wellbrook-based antenna functions superbly, and its low-noise design helps hold down QRM from the nearby cabins (which unfortunately have been “upgraded” recently with noisy cold fluorescent [CFL] light bulbs). The area around the Cape Lookout cabins used to be superbly low noise and suitable for radio listening, but now it is more of a challenge than before. The Wellbrook FLG100LN is perfect for the situation though; Wellbrook ALA1530LN Pro and ALA1530S+ 1-meter loop antennas work commendably at the park too.

The Wellbrook FLG100LN module with a home brew RFI choke in-line

A 2K ohm variable potentiometer is protected from the elements in a small plastic bag. The “pot” is adjusted for the best nulling of medium wave stations off the back side of the antenna’s reception pattern.

The “tent pole loop” antenna is strapped to a fence railing with ultra-strong Gorilla Tape to keep the 7-ft. square loop vertical.

On with the recordings…

For the FDM-S2 and HF+ comparisons I used the SDR-Console V3 software. Every parameter was identical for the receivers–sampling bandwidth, filter bandwidth, AGC, mode and so on.

Take a critical listen to the weak signals recorded with the SDR receivers, identified as only “Radio A” and “Radio B”. A link to a poll is at the end of this article; please indicate which recording of each pair has the most intelligible audio in your opinion, and submit your choices when you’ve made up your mind on each audio clip. After a week or so I’ll post the results of the voting, and identify the receivers.

9.615 MHz, LSB, Radio A

9.615 MHz, LSB, Radio B (note: the same male announcer heard in clip “A” begins at 00:14 in this “B” clip)

9.730 MHz, USB, Radio A

9.730 MHz, USB, Radio B

7.230 MHz, S-AM, Radio A

7.230 MHz, S-AM, Radio B

9.860 MHz, S-AM, Radio A

9.860 MHz, S-AM, Radio B

Note on 7.230 MHz recording: this was an interesting frequency, as the signal was tightly surrounded by a very strong local 40m ham radio LSB station as well as a strong China Radio International signal. There were other strong amateur and broadcast stations within 30-50 kHz of 7.230 MHz, also. This A-B test more than the others may indicate receiver performance in a strong RF environment on a crowded band.

Ready for the poll? Register your votes at the Google Docs form below:

https://tinyurl.com/ya38wj69

In a week to 10 days I’ll post the results in another article. NOTE: I haven’t provided a “both sound the same” choice in the poll to encourage you to ‘dig deep’ into the audio and listen critically–to find something that stands out in one clip versus the other.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington. He’s a regular contributor to the SWLing Post.

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Brief Medium Wave Tests of the HF+ and FDM-S2 SDRs in a Suburban Location

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The AirSpy HF+ is the new SDR on the block, but how does it compare to the Elad FDM-S2 which is more than 2-1/2 times its $199 price? My main interest is finding out how they compare in a very RF-quiet DXpedition setting, but today I compared the two briefly from my home in Puyallup, Washington (near Seattle).

The receivers were connected via a two-way antenna splitter to the output of a Wellbrook ALA1530S+ loop antenna. I monitored during mid-afternoon local time to ensure that all my MW locals in my suburban location would be at full power, for the best test of the radios’ overload performance. The Wellbrook active antenna is rather “hot” and sometimes overloads receivers during the daytime unless attenuation is added to the signal chain.

I noted there were no truly weak medium wave signals available during the session so comparing sensitivity wasn’t appropriate. However, the band was full of strong daytime MW signals.

It became apparent quickly that the upstart HF+ provides strong competition to the Elad SDR. Clearly, the AirSpy’s trade-off is bandwidth for raw performance at lower cost–approx. 660 kHz alias-free coverage versus about 6 MHz maximum for the Elad.

Using the same center L.O. (local oscillator) frequency, short recordings were made with both receivers on the same receive frequency, same bandwidth, AGC setting, etc. To approximate the 660 kHz coverage of the HF+, I set the FDM-S2 to its 768 kHz sampling rate, the closest available setting to 660 kHz wide coverage.

Here are the results on 1540 kHz, just 10 kHz away from a strong signal on 1550:

AirSpy HF+ – 1540 kHz

Elad FDM-S2 – 1540 kHz

What’s wrong with the above audio picture? The FDM-S2 is clearly overwhelmed by the strong RF on the upper end of the MW band. Visually, the spectrum looked like this with the Elad:

Elad FDM-S2 waterfall/spectrum (1540 kHz)

The noise floor rose by approximately 20 dB due to the overloading. The HF+ showed a normal waterfall and spectrum display while tuning 1540 kHz:

AirSpy HF+ waterfall/spectrum (1540 kHz)

Let’s listen to two more audio clips, this time from 720 kHz which is adjacent to very strong 710 KIRO, the ESPN affiliate in Seattle:

AirSpy HF+ – 720 kHz

Elad FDM-S2 – 720 kHz

This time the difference is subtle, but I think you’ll agree there is a greater amount of “crunchy” background distortion noise on the FDM-S2 recording. I found this to be the case in each instance where I compared receivers on frequencies adjacent to strong locals.

I no longer own a Perseus SDR, but that receiver handles the entire MW band at this location without overload using the same Wellbrook ALA1530S+ loop.

I’d like to emphasize that these were brief, somewhat casual AirSpy HF+ vs. Elad FDM-S2 tests. I expect that in a more forgiving RF environment, both receivers will be equally adept and digging out weak weak and challenging DX signals. I plan to investigate this very scenario in a few weeks at a quiet location on the Oregon coast.

Side note: I have two HF+ units and they can operate concurrently without problems for full medium wave band coverage with HSDSR software, even when both are recording IQ WAV files.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington. He’s a regular contributor to the SWLing Post.

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