Honestly, I never used this much, but now I'm convinced this is a useful tool! The Icom 7300 SWR graph is very easy to use. The 7300 has an amazing autotuner, but it doesn't tune antennas with a real high SWR. For that there is the Emergency Tuner. You could try plotting an SWR graph on a band. It should tell where the E-Tuner needs to be activated and where it doesn't. This little tool can also tell us if something in the antenna has changed or if there is something wrong. We can even save these graphs in a screen shot (pressing the POWER button) and refer back to them at a later date. So if you own a Icom 7300, or you're curious, have a look:
Not sure what I am doing or not doing right.... I can never seem to get this feature to work properly and recall or replay a plot? Must go back to the full manual ..... if all else fails read directions (so unlike me, I usually cant put a manual down)
Yeah, I know what you mean. It saves the last plot. If I hold down the recall button (1 sec) it takes me back to the last plot (freq) and I can view it, but that's all I can manage. It's easy enough to complete a plot though. I think the directions on pg. 3-13 in the full manual are lacking a bit. Best 73!
30% power of a 100 watt radio is around 30 watts of output. So how do you fulfill the legal obligation of station identification while QRM'n others? I don't believe it would be an issue if the power level was extremely low but 30 watts!! Am I missing something here??
I believe you are correct. I thought the same when reading the instructions. I should have read it closer because it says "If necessary, adjust the RF power to approximately 30 W". I have done it with 10 watts on other occasions and it works. Icom also says: NOTE: Before transmitting, monitor the operating frequency to make sure you will not cause interference to other stations on the same frequency. That can be done with the scope too.
I don't believe spread spectrum transmissions are permitted on HF, that is what is happening because it transmits on multiple frequencies in sequence. Maybe if Chip W1YW or someone more knowledgeable about this would find this thread that person could clear this up or add some insight, to me something does not seem right, operator wise and FCC legal wise. Unless you would be able to check every frequency at the sample points for the graph the transmission has a very high probability of interfering. It seems you would also have to transmit your call sign at every data point????
Without regard to power levels, isnt this what most antenna analyzers do too. So the Icom has a rudimentary QRO antenna analyzer feature. I guess that no different than the many times I hear/see the warbled carrier of some lid tuning up and then spinning the dial up and down the band!!!!
Isn't that the truth, with the spectrum scopes I can actually see what was once suspected. I am going to play with my 7300 SWR graph before commenting anymore because I cannot get mine to work so obviously I have no clue to what is going on.
Nah, the radio doesn't do *any* transmission on its own. All it does is step the frequency after each transmission and record the SWR. You're the one making each transmission. It tunes to each frequency first, so you can sit there and listen to make sure the frequency is clear. You don't have to do it in RTTY mode and it will work fine in SSB, so you set it up, press the "play" button, then listen to see if the frequency is clear, key the mic and say something like "Testing, AE6AM", then un-key the mic and it shifts to the next frequency automatically and you listen and then transmit again and repeat until you've captured all the SWR samples. If a frequency is in use you can just press the "stop" button to leave the testing mode without having transmitted on that frequency. It would be nice if you could just skip to the next frequency point, but I haven't found a way to do that. So all nice and legal in every respect I think as long as you use it correctly. P.S. A couple other notes just from observation after a couple tests: It seems to drop out of "play" mode if the SWR goes above 1.5 (the bars are colored red above the 1.5 line). If you leave the tuner enabled then it seems to leave the tuner in-line with the last tuning solution, but inhibits auto-tuning on transmit as far as I can tell. Haven't played with it enough to fully characterize this behavior though. G.
Yes, indeed +1 on the spectral display observation! I dont kniw how I ever got along without one. Certainly makes you aware of all sorts of QRM/QRN..... I also cant address the topic much better until I spend more time figuring it out. Lots of subtle features that I am just now discovering with this radio.
That is true and very good point about having to manually transmit at each increment of freq. That is something an antenna analyzer does not do. I wonder at what power level does a diagnostic signal source no longer be considered an emmision? Perhaps it is the SWR beyond the limits or the auto antenna feature that fails on the plots I tried to intiate. Not sure, because my radio is already being loaded into my Expert Amps own predetermined auto antenna tuner memory settings . .... I need to spend less time online and more time on the radio!
