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ICOM 7300 New at $850 / How low will this drive used market?

Discussion in 'Ham Radio Discussions' started by NN2X, Dec 4, 2019.

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  1. KK5JY

    KK5JY Premium Subscriber QRZ Page

    Okay, that may be a fair assessment of testing. Admittedly, there has been a lot of work done over the decades to make conversion receivers better and better at selectivity.

    I'm having some difficulty understanding how an overloading issue could slip by the wide-spaced compression and/or DR tests, but fortunately, my lack of imagination doesn't define the state of the art. :)
     
    N0TZU likes this.
  2. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    It's not that the traditional tone tests don't work. It's that the actual use case of the radio can differ so much from the test conditions because of its wide passband.

    Here's what I think is happening:

    For a DSP receiver with only a band pass filter before the ADC, every signal and noise on the band adds (in RMS fashion) to the total signal that the ADC will convert. On a quiet band the performance will seem to be similar to what the test reports because there are very few strong signals and the sum isn't taxing the ADC dynamic range.

    But on a very noisy and/or very busy band, the sum of all that power in the wide passband uses up a great deal of the dynamic range. Thus the operator may not hear the weaker stations and the receiver appears to be performing poorly.

    Under the same conditions, a superhet has a far smaller total signal coming into the detector because of the much narrower "roofing" filter in the IF . So much of the dynamic range is preserved and the receiver can still hear weaker stations.
     
    N2EY, K7TRF, KK5JY and 1 other person like this.
  3. KE0EYJ

    KE0EYJ XML Subscriber QRZ Page

    I've said my bit about the 7300, which I had at this QTH for 2 years. Sold it, now have the FTDX3000. Can work 40m to the USA, again (from HL1ZIX location in Seoul).

    The 7300 is a great high-band value radio. On the low bands, it is in some serious need of filtering. IP+ never impressed me ... at all. Even after the update. I'm really curious about how people will feel about the 7300 once band conditions improve, and things get really busy on 40m?

    As for the price selling new at what it is -- at the very least, it should pretty much end new radios coming out with a need for additional things like voice recording chips.

    Too bad there's no simple way to plug a 3khz/6khz roofing filter into the 7300 for SSB. But then fewer would spend money on the 7610.
     
    Last edited: Dec 8, 2019
    N0TZU and KE0GXN like this.
  4. N1FM

    N1FM Premium Subscriber QRZ Page

    Good point. It's an entry level rig with an entry level price.
     
  5. SV2HZF

    SV2HZF Ham Member QRZ Page

    7610 or Flex or Anan have roofing filters?
     
  6. KV6O

    KV6O Ham Member QRZ Page

    A narrow roofing filter would defeat the SDR's wide look at a chunk of spectrum. More expensive radios do this, however - the new Yaesu FT-101D uses a hybrid approach, with an SDR spectrum scope and a superhet (with roofing filters) doing the actual decoding/demodulation. More expensive SDR's have more expensive ADC's with wider dynamic ranges. And older radios with SDR add-on's were already doing this - SDR for the spectrum display, and more conventional receiving techniques for the demodulation. My K3+P3 is an example of this - the P3 provides the wide view in the IF, and the K3 with its roofing filters provide the selectivity.

    This is why there is a market for more expensive radios. Just because a radio is an SDR doesn't mean it's "better".
     
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  7. SV2HZF

    SV2HZF Ham Member QRZ Page

    Neither better nor necessarily worse.
    The question is not whether there are better radios than the 7300 - there are - but whether this affordable "entry level" but fully loaded and greatly capable radio gave them all a good run for their money.

    And this is a fact that cannot be ignored nor undermined by anything anyone says.

    73
     
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  8. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    And why the K4 will offer a superhet option for those who often encounter extreme situations, even though I expect that their ADC will be top grade.
     
    KV6O likes this.
  9. KE0EYJ

    KE0EYJ XML Subscriber QRZ Page






    The 7610 does have a kind of preselector filtering, which the entry-level 7300 lacks. Per Icom:

    http://www.icomamerica.com/en/products/amateur/hf/7610/default.aspx
     
  10. KV6O

    KV6O Ham Member QRZ Page

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