HFU HF Underground

Technical Topics => Equipment => Topic started by: NJQA on May 25, 2023, 1120 UTC

Title: State of HF transceiver art
Post by: NJQA on May 25, 2023, 1120 UTC
This is from the 2023 CTU, and discusses the performance of current HF transceiver offerings.  Most of the discussion is on receiver performance.

Note that it says 60,000 Icom IC7300 radios have been sold.  This is surely the most popular HF radio ever.  I have heard anecdotal stories of SWL’s buying them just to use as a receiver.

https://www.contestuniversity.com/wp-content/uploads/2023/05/Transceiver-Performance-Selection-of-a-Radio-2023.pdf
Title: Re: State of HF transceiver art
Post by: RobRich on May 25, 2023, 1237 UTC
Lots of good info, but probably the best advice in the document:

"Antennas are more important than the rig model."

Several in the SWL crowd also like the IC-705. Quite pricey for just a receiver, but admittedly the ergonomics are well suited for both home and portable use compared to its larger desktop siblings.
Title: Re: State of HF transceiver art
Post by: Josh on July 15, 2023, 0059 UTC
Rob Sherwood knows his way around a good receiver. He keeps the rx performance list updated, all of us can profit from perusing said list;
http://www.sherweng.com/table.html
For those who don't grasp the details of the rx list you might click where it says (Terms Explained: DOC PDF) and get educated. He also has multiple utube vids on the subject that are worth the time.
https://www.youtube.com/results?search_query=sherweng

Many rx boxes are listed, not just transceivers.
For a long time Hilberling held the top spot, then yazoo came out with the 101D and blew everyone away and it's still on top. In the end, if your rx hears what you want that's all one needs right? That said, understanding what goes on in a given rx box is of some interest to radionerds so I say learn all you can about them and what is state of the art today.

Also interesting Icom is selling so many 7300s, I think their other big seller was the 706 series. Wonder how many R75s they sold, they ran from 1999 to 2015 or thereabouts. I note the R71 has 62dB close dynamic range, while the R75 has 67dB, much better, something I figured would be opposite, with narrow spaced dynamic range being the holy grail of the sherweng testing.
Title: Re: State of HF transceiver art
Post by: Ray Lalleu on July 15, 2023, 1024 UTC
narrow spaced dynamic range being the holy grail of the sherweng testing.

The narrow space dynamic range is that for CW contesters, specially on Field days gathering spots.
If you have no transmitting neighbors, if you listen mainly to audio signals, you should look to a good set of all the results.

The Sherwood tests are done only on some ham bands, not elsewhere I think, and probably only via 50 ohms antenna sockets.

The new transceivers are looking more and more designed for ham operating needs, less and less for general listening.

I'm wandering about how good should be the wide space dynamic range and LO noise when the HF bands are full of thunderstorm noise and rolling crashes.

Of course, the receiving antenna is more important. Are there any sets better suited for low noise low level (and high impedance) receiving antennas?
Title: Re: State of HF transceiver art
Post by: ChrisSmolinski on July 15, 2023, 1651 UTC
Lots of good info, but probably the best advice in the document:

"Antennas are more important than the rig model."

Agreed, this cannot be over-emphasized.

Also, don't forget about diminishing returns. Once you get to a certain point in specs, you end up paying a lot more money for a trivial amount of additional performance. Which you may never even notice.
Title: Re: State of HF transceiver art
Post by: RobRich on July 15, 2023, 1904 UTC
Agreed as well on diminishing returns. That said, Yaesu does show us a welcome performance-versus-price trend in HF RF development IMO. The "entry-level" FTDX-10 and FT-710 models are now delivering receiver performance specs matching and even exceeding many other still relatively modern-era HF radios costing up to several times their prices.

Do those specs translate often directly to real-world performance for most people, especially those in typical higher-noise HF areas these days? Not really, again for most outside of maybe serious contesters, but at least they still show continuing advancements in HF receiver design.
Title: Re: State of HF transceiver art
Post by: Josh on July 18, 2023, 1843 UTC
What I like to see in a given hf rig is a 90dB imd3, 120dB blocking, -130dBm sensitivity without preamp, and excellent audio. Those specs get you to the point where, barring the band noise, the transmitters distortion is the limiting factor in reception with such a system.

A lot of rigs come close enough to the above specs to be more than usable. With the most common background noise on hf being around -120,  anything that hears down to -125dB will be more than enough unless you have poor antennas, then some additional gain can help.

As to antennas, I'd rather have an outstanding rig and mediocre antenna than the other way round. After all, if the background noise comes up when you connect the antenna to the antenna socket, that's about all you need. That said, a beam is the closest thing to cheating for radionerds.