I picked up an unmolested NASA Target HF3 receiver and am pretty pleased with it.
No, it will not be at the top of the Sherwood testing list.
There are a lot of versions of these things out there, basically all the same since about 1998 or so. Nasa Marine, Si-Tex, Target, AKD, even Lowe SRX100. Plenty of reviews out there so I won't just rehash them here.
Mine is a later version that has mostly surface-mount components, aside from the usual filters, transformers, and a small handful of electrolytic caps.
I got it mainly for casual ssb/cw monitoring, and it does quite well even with the wide filter. The ssb filter is an inexpensive 6-pole LT455IT, about 4khz wide. Usable, but in ssb I needed a high frequency audio rolloff, so I just did a simple RC lowpass across the speaker. Without this mod, the high-frequency audio was causing listener fatigue.
This consisted of lifting the positive lead of the speaker wire, and inserting a 10 ohm, 2 watt resistor from the junk-box in series. Directly across the speaker I placed about 15uf of non-polarized caps. Anything from about 4.7 to 20uF should do according to how much you want to rolloff. I actually used what I had on hand - two 22uf polarized electrolytics back to back (negative to negative) giving me 11uf total, and then a 4.7uf bipolar that I had on hand in parallel to that. Not critical, but DO use non-or-bipolar caps for this.
That's more like it. Next to my Kenwood 590s, it is roughly similar to turning off the preamps, and cranking the filters open to about 3 to 3.4k. Without the audio rc rolloff mod, it was just too harsh.
I wanted a bit of lower end boost, so I paralleled a 470uf polarized electrolytic with the last audio output cap on the bottom of the board - although the low end is restricted to the speaker bandwidth itself. But I felt it got me a little bit better midrange response. Probably not necessary for most people.
I'm running a variety of outdoor antennas, like my 33-foot vertical, and in my location, have no major problems. However I have on hand a PAR BCB filter, and an MFJ 1046 passive preselector. So far, I haven't had to use them.
In the end, I have been dissatisfied with most of the low-end radios, like the Grundig 750, Tecsuns and the like, since for *ME*, they overload on even modestly strong signals, or have very poor IF or AF AGC and cover this up with heavy-handed rf attenuation. So far, the Target HF3 is at least trying to act like a bigger radio.
The agc is what I'd call medium. Much like an R75, or Icom 718. I can copy ssb and cw just fine, although of course I'm doing so with a wide filter, so the brain filter will have to be used. Forget contesting - this is a casual rig.
This audio mod is about as far as I'm going to take it. There certainly is the capability for additional mods, like better filters, connectors, backlights and so forth that can be done. In fact, an upgraded "HF4" version is out there that uses a nicer 2.6k ssb filter, so-239 jack, backlighting etc, but may not be as easy to find as an HF3.
It's rated for 300ma, but under my normal listening conditions, I'm drawing no more than about 150-200ma at most.
I had given up on my search for a casual ssb / hf monitoring rx, having been dissatisfied with the Grundig 750, Tecsun's, and others - see my reviews here for why - and feel that the Target HF3 just might be a keeper - with audio mod! I've got to keep it all in perspective at this price / performance level. I have a CommRadio CR1 as well that is getting jealous of this newcomer to my shack, so no hard feelings anybody!
No, it will not be at the top of the Sherwood testing list.
There are a lot of versions of these things out there, basically all the same since about 1998 or so. Nasa Marine, Si-Tex, Target, AKD, even Lowe SRX100. Plenty of reviews out there so I won't just rehash them here.
Mine is a later version that has mostly surface-mount components, aside from the usual filters, transformers, and a small handful of electrolytic caps.
I got it mainly for casual ssb/cw monitoring, and it does quite well even with the wide filter. The ssb filter is an inexpensive 6-pole LT455IT, about 4khz wide. Usable, but in ssb I needed a high frequency audio rolloff, so I just did a simple RC lowpass across the speaker. Without this mod, the high-frequency audio was causing listener fatigue.
This consisted of lifting the positive lead of the speaker wire, and inserting a 10 ohm, 2 watt resistor from the junk-box in series. Directly across the speaker I placed about 15uf of non-polarized caps. Anything from about 4.7 to 20uF should do according to how much you want to rolloff. I actually used what I had on hand - two 22uf polarized electrolytics back to back (negative to negative) giving me 11uf total, and then a 4.7uf bipolar that I had on hand in parallel to that. Not critical, but DO use non-or-bipolar caps for this.
That's more like it. Next to my Kenwood 590s, it is roughly similar to turning off the preamps, and cranking the filters open to about 3 to 3.4k. Without the audio rc rolloff mod, it was just too harsh.
I wanted a bit of lower end boost, so I paralleled a 470uf polarized electrolytic with the last audio output cap on the bottom of the board - although the low end is restricted to the speaker bandwidth itself. But I felt it got me a little bit better midrange response. Probably not necessary for most people.
I'm running a variety of outdoor antennas, like my 33-foot vertical, and in my location, have no major problems. However I have on hand a PAR BCB filter, and an MFJ 1046 passive preselector. So far, I haven't had to use them.
In the end, I have been dissatisfied with most of the low-end radios, like the Grundig 750, Tecsuns and the like, since for *ME*, they overload on even modestly strong signals, or have very poor IF or AF AGC and cover this up with heavy-handed rf attenuation. So far, the Target HF3 is at least trying to act like a bigger radio.
The agc is what I'd call medium. Much like an R75, or Icom 718. I can copy ssb and cw just fine, although of course I'm doing so with a wide filter, so the brain filter will have to be used. Forget contesting - this is a casual rig.
This audio mod is about as far as I'm going to take it. There certainly is the capability for additional mods, like better filters, connectors, backlights and so forth that can be done. In fact, an upgraded "HF4" version is out there that uses a nicer 2.6k ssb filter, so-239 jack, backlighting etc, but may not be as easy to find as an HF3.
It's rated for 300ma, but under my normal listening conditions, I'm drawing no more than about 150-200ma at most.
I had given up on my search for a casual ssb / hf monitoring rx, having been dissatisfied with the Grundig 750, Tecsun's, and others - see my reviews here for why - and feel that the Target HF3 just might be a keeper - with audio mod! I've got to keep it all in perspective at this price / performance level. I have a CommRadio CR1 as well that is getting jealous of this newcomer to my shack, so no hard feelings anybody!
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