[Premium-Rx] Receivers

[Charles Steinmetz]

Michael wrote:

>The TenTec 340   *   *   *  manual tuning is very slow.  It's more 
>of a fine tune rather than for swift navigation.

Like many, many radios, the RX340 manual (knob) tuning follows the 
UP/DOWN STEP (keypad) tuning interval.  That is, each count of the 
rotary encoder changes the frequency by whatever amount is set for 
the STEP control (a range of selections from 1Hz to 1MHz).  So, the 
manual tuning can be very slow to insanely fast depending on the STEP 
setting.  I find the 50Hz step position to be about right for manual 
tuning on the RX340.  The JRC NRD-545, Harris RF-590, WJ 8711, and 
many, many other receivers all act this same way, with some slight variations.

Personally, I find this a particularly useless arrangement.  I 
usually want the UP/DOWN (keypad) tuning steps to be the same as the 
band channelization (generally 5, 9, or 10 kHz on the MW/SW bands, 
sometimes higher at VHF/UHF), but at the same time I want the knob 
tuning to be much, much slower -- a good rate for scanning and fine 
tuning.  The Drake R8B is the only premium receiver I'm aware of that 
allows this.  Its tuning knob always tunes at a good 
band-scanning/fine tuning rate, and its UP/DOWN (keypad) tuning 
varies according to the band channelization.  (The Drake SW-8 also 
works this way.)

The RX340 also has some strange limitations, due (I suspect) to 
insufficient DSP horsepower.  The notch filter is unavailable in AM, 
SAM, ISB, and at BWs above 4kHz in LSB/USB.  The PBT is unavailable 
in SAM and ISB.  The BW is limited to 4kHz and above in SAM, and is 
not adjustable at all in ISB.  Ergonomically, you have to cycle 
stepwise through the modes and tuning steps, and it uses one control 
to adjust BW, BFO, PBT, notch, AGC, squelch, and noise blanker.  The 
WJ 8711/HF1000 has similar quirks.

Best regards,

Charles