Kevin, FYI...here is a little email i sent to another ham last week on the topic.
Hi, Roger. Regarding my SDR. I find it to be both great, and a bit of a pain! I did not want to spend lots of money, nor do I possess the skills to build an inexpensive one from a kit. My very talented friend , W3VG, bought a softrock kit 3 weeks ago and despite his talents, he is finding it quite a challenge. So, I bought a SDR-IQ for $499 after selling a 21 year old TS-440 for around $400. Having wide (up to 190 khz) spectrum to visually see signals is really amazing, hard to imagine being with out it now. Visually spotting DX is much easier than twirling a dial, you also find stations not yet announced on a DX cluster. On a crowded band, it is not as useful because it can be a pain to click on hundreds of signals. However, on a no-so-active band, it is fun looking for tiny whispers of signals and then hearing a CQ call. My SDR has the ability to listen with 3 VFOs (depending on the software used), so you can actually hear three different parts of the spectrum at the same time. I also can have two signals , one playing via the right speaker and one via the left, if I choose. I can also listen to LSB AND USB, CW and SSB , various combinations ...at the same time. I find the sensitivity to be not significantly different than my TS2000, if I can hear it on the TS200, I can usually hear it on the SDR-IQ. There is a bit more white noise hiss on the SDR but I can handle that. You can use noise reduction features, but I usually just ignore the noise. There will probably be times where my TS-2000 hears somethings the SDR-IQ does not, but not on a regular basis. If you do CW work, CW Skimmer is great with an SDR. It will find all the CW signals that are sending a CQ within the 192 hz span (or more if your SDR allows) and list them on a screen for you to click on and QSY to. Very useful. The pain in the neck part is two-fold. One , transmitting on one antenna and receiving via the SDR on another, is a hazard. If not careful, you can blow the front end of the SDR if too much RF gets in. I bought a device that protects the front end , there are 3-4 types available. This apparently applies to ALL SDRs, not just the SDR-IQ. The SDR-IQ designer tells me that the ONLY way to be 100% safe is to disconnect the SDR while transmitting. That can be a pain. What I do is.. I have a coax switch on my desk and I switch the SDR's antenna to ground before I transmit. So, there is that added step. Not a major hassle unless doing rapid fire work, like in a contest. Having a dedicated SDR transceiver using just one antenna would presumably solve this problem. The commercial devices you can buy either detect the RF and invoke protection circuits (the one I have) or use a PTT line and switch the antenna to ground (more expensive, $120) There is an application , called rig-sync , that I use. One click of a mouse and my TS-2000 moves to the frequency and mode that my SDR is in. Very useful.I also have a Microkeyer interface, with the software that comes with that, I can also control my TS--2000 AND SDR-IQ My SDR does not require a high end sound card, some others do. When you run an SDR, you can SEE large chunks of spectrum, but you can't hear large chunks. Some SDR software allows your to hear as much as 12 khz of audio, others just 3-6 Khz. That is not a big problem because your ears can not handle all those signals. Where it is an issue is for digital modes. Digital mode software has not caught up with SDRs yet. All, except Multipsk, will decode whatever audio spectrum you can get out of the digital mode software. usually around 4 khz. So, even if the SDR software allows larger chunks of audio, FL-digi, DM780, MixW, et al, will not decode more than the standard. Multipsk has a feature that WILL decode from an SDR directly. 48 Khz of spectrum is monitored and it will even detect RS-ID over that entire range, VERY cool. Multipsk does not support all SDRs...yet . So, in my case', it accepts the signal and works nicely, BUT I have to 'start" the SDR-IQ via SDR software. Thus I have two CPU demanding applications running and it taxes my low end PC. My sons Optiplex 270 with a 2.7 CPU runs all of this without problem, so it does not take a whole lot more CPU. Multipsk may soon include more SDR support and then I would not have to use two applications at the same time. DM780 is also expected to add SDR support. Some SDRs like Sofrock can only do a small chunk of spectrum at a time (around 40 khz) , some do the same as mine (192 khz) and some (in the $1000-2000 range) do 2-3 mhz broken down in to several chunks per band. If I was doing it again, I would think more about getting the ability to monitor ALL bands. I did not consider a Flex radio because that requires a high-end sound card and computer, by the time you are finished, it will cost more than $3000. Andy K3UK --- In digitalradio@yahoogroups.com, "Gmail - Kevin, Natalia, Stacey & Rochelle" <spar...@...> wrote: > > Hi All, > > I am posting this question in this group as I know their are a few of you > using SDR modules. > I am looking at getting one soon to use in my shack (bit hard for portable), > but I don't know which way to go? > > I have looked at the following few modules, SDR-IQ, Softrock, Flexradio and > Genesis to name a few. > I am impressed with the SDR-IQ, but it is quite pricey and it's only RX. I > would like to be able to RX/TX. I could however use my Kenwood for the TX > side of things. > I did look at the SDR-14 but at twice the price over the SDR-IQ without much > difference, won't be going that way. > > Anyone got their thoughts, please email me directly if you do not wish to > clog up the group. Andy, I'll try you on Skype again later (we keep missing > each other). > > > Get Skype and call me for free. > > Kevin, ZL1KFM >
