The 756 has served me well since the day I bought it. It has DSP but unlike some later rigs which had full-time DSP, on the 756 you can turn it on or off. This is a great feature if you’re working in a neighbourhood with another ham. With Harry, VA3EC, 360 meters north of me, it’s a big advantage to take the DSP out and add 12db of front-end attenuation. With that setup I can work within 5 kHz of him without much effort.
The 756 has one issue and that’s the front display panel has some bars (a known issue) but that affects the selling price 🙂
It’s called the Flexradio 1500 (Oh here he goes again.)!
Last weekend was the CQ 160 meter CW contest. So just for fun I wired up the IC-756 and the Flexradio 1500 to an A/B switch and I listened to the same signals using the same antenna by switiching back and forth.
I’ve always found the CQ 160 CW contest to be a tough test of equipment. First my only 160 antenna is an Alpha Delta 160/80/40/30 sloper that comes off my tower at around 45 feet and is terminated by tying it off from a fence post about six feet off the ground. This is so not good. Also I don’t have a Beverage antenna or K9AY loop for receiving so I can’t hear anything due to my noise. Being situated less than 500 meters from the north shore of Lake Ontario means I don’t have any elevation.
So lots of noise, no elevation, an antenna that acts more like a dummy load, only 100 watts right now and what do you get? A headache and few QSOs.
So how did the rigs compare?
I tuned (I think) N4ZZ running early on Friday night. He was about S9 (or better). Many of the stations calling him I could barely hear or not hear at all.
On the 756 N4ZZ sounded terrific. Beautiful CW note and lots of strength. I brought in both 500 Hz CW filters (making for an effective filtering around 350 to 400 Hz) and I listened intently.
On the 1500 I reduced the filter bandwidth down to 400 Hz.
I pipped the audio to ordinary (crappy) computer speakers on both systems so as to avoid better audio from better headphones (I’ve got at least six pair.)
First thing I noticed was the noise between the 756 and 1500 read around S5 on both receivers but on the 1500 the background noise wasn’t anywhere near harsh. While listening to stations calling I could clearly hear stations on the 1500 that were less readable on the 756.
On both receivers I could hear other less strong stations just off frequency but when I reduced the bandwidth on the 1500 I could easily reduce or eliminate the signals.
So impressive was the difference I asked Marion, VE3HEN, (my XYL and SHMBO*) to witness the difference. (This was the beginning of the new computer campaign on the home front.)
So what was the end result? The 1500 was quieter and much less fatiguing to listen to. The 1500’s ability to filter down to 25 (yes you read that right) Hz without any noticeable deterioration of the quality of the CW note was amazing. Also there’s no comparison between the full-screen panoramic display on the 1500 compared to the cramped 2″ display on the 756. …and so the 756 is up for sale 🙂
So is everything perfect?
NO. Not by a long shot. I’m using really crappy computers that don’t have enough CPU power to run an SDR properly. If my CPU goes over 30 per cent usage it can affect the 1500’s keying. Nothing like have the computer drop a character of your call sign in the middle of a contest.
Also I’ve got the 1500 working in one window and Writelog working in a second which is activated by the mouse hovering over it. This system works better than it sounds. I can establish rig control and fire the CW memories in Writelog but it taxes the computer and I’ve screwed around with virtual ports and messed up both machines.
The simple answer to better SDR is a new more robust computer which is on the drawing board.
BTW the LDG Pro 200 autotuner worked perfectly (read the furbished manual) on 160!!! This is an amazing feat for such a small box. Once I got the autotune memories setup I could QSY anywhere on the band without the tuner readjusting itself. The Palomar 100-watt amplifier never even got warm despite putting out 60 to 80 watts into the autotuner.
I’m going with a Flex 300o or whatever is new once I’ve got $1500 in cash. The new computer will have sufficient horsepower to run it. Then it comes down to which amp and I’m leaning toward the Acom 1000 or Tokyo Power HL-1.2 or 1.1. I’ll likely go for the LDG high-power autotuner as well and then I’m done… 🙂
* SWMBO – She who must be obeyed from Rumpole of the Bailey.