DC to Light Recommendation?
 

Any recommendations on the best products to achieve as complete a range of
reception and transmission as possible? All band, all mode, CW, VLF, Low
Band, VHF, UHF, AM aircraft, etc.? Kenwood TS-2000? Harris? Is there an
all-in-one radio? I've got six old radios (tube sets mostly) to accomplish
this, and would like to get more space and tech efficient. I just don't
know the new products. Suggestions?

On Wed, 02 Jul 2003 06:17:41 GMT, "Steve Cohen"
wrote:

Any recommendations on the best products to achieve as complete a range of
reception and transmission as possible? All band, all mode, CW, VLF, Low
Band, VHF, UHF, AM aircraft, etc.? Kenwood TS-2000? Harris? Is there an
all-in-one radio? I've got six old radios (tube sets mostly) to accomplish
this, and would like to get more space and tech efficient. I just don't
know the new products. Suggestions?


These days it is not so much of a problem to construct a receiver that
can be tuned to any frequency between 9 kHz and 9 GHz, the problem is
building a receiver that is actually usable in that frequency
range:-).

If such large frequency range would be attempted, the local oscillator
phase noise would kill the performance completely. Wide open receiver
front ends will also very easily overload, producing a huge number of
spurious responses.

Doing a high quality DC to daylight receiver would require at least 3
or 4 different receiver topologies. One perhaps from 9 kHz to 1500
kHz, one from 1 MHz to 200 MHz, one from 100 MHz to 10 GHz and one for
frequencies above 10 GHz (if needed).

Each subreceiver would require at least a dozen of fixed input filters
or at least 4-5 tunable front end filters each, since it is hard to
make a tunable filter with a frequency range larger than 1:3. Even
with strong mixers a selective front end filter will help in keeping
the spurious responses at a reasonable level.

I would strongly recommend that you keep your old tube equipment,
since they will very clearly outperform any "DC to daylight" all in
one units at least in LF and MF.

In HF, a DC to daylight receiver will outperform the tube set in
frequency display accuracy and frequency stability, but _definitively_
not in spurious response. At frequencies above 15-30 MHz a new rig may
outperform a tube rig in sensitivity.

Above 50-100 MHz even a mediocre modern receiver may outperform an old
tube receiver.

Paul OH3LWR

On Wed, 02 Jul 2003 06:17:41 GMT, "Steve Cohen"
wrote:

Any recommendations on the best products to achieve as complete a range of
reception and transmission as possible? All band, all mode, CW, VLF, Low
Band, VHF, UHF, AM aircraft, etc.? Kenwood TS-2000? Harris? Is there an
all-in-one radio? I've got six old radios (tube sets mostly) to accomplish
this, and would like to get more space and tech efficient. I just don't
know the new products. Suggestions?


These days it is not so much of a problem to construct a receiver that
can be tuned to any frequency between 9 kHz and 9 GHz, the problem is
building a receiver that is actually usable in that frequency
range:-).

If such large frequency range would be attempted, the local oscillator
phase noise would kill the performance completely. Wide open receiver
front ends will also very easily overload, producing a huge number of
spurious responses.

Doing a high quality DC to daylight receiver would require at least 3
or 4 different receiver topologies. One perhaps from 9 kHz to 1500
kHz, one from 1 MHz to 200 MHz, one from 100 MHz to 10 GHz and one for
frequencies above 10 GHz (if needed).

Each subreceiver would require at least a dozen of fixed input filters
or at least 4-5 tunable front end filters each, since it is hard to
make a tunable filter with a frequency range larger than 1:3. Even
with strong mixers a selective front end filter will help in keeping
the spurious responses at a reasonable level.

I would strongly recommend that you keep your old tube equipment,
since they will very clearly outperform any "DC to daylight" all in
one units at least in LF and MF.

In HF, a DC to daylight receiver will outperform the tube set in
frequency display accuracy and frequency stability, but _definitively_
not in spurious response. At frequencies above 15-30 MHz a new rig may
outperform a tube rig in sensitivity.

Above 50-100 MHz even a mediocre modern receiver may outperform an old
tube receiver.

Paul OH3LWR