QSX radio + 630m :)
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True, but very few people need *linear* transmitters (amplifiers) on
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630m. I suspect most who are on that band aren't going to be doing a lot of portable operating so an add-on amplifier shouldn't be too burdensome. This makes the radio's job easy. It's simple and cheap to build a 100W+ Class-E or Class-D amplifier to follow a radio. My very inexpensive 100W 630m amp needs only 1 milliwatt of drive and was built in an afternoon. I would much rather see 2200m included myself. ;-) But I'm not expecting nor asking for either band to be included as the demand would almost certainly be too low to make it worth the design effort. FWIW I built a simple 2200m amplifier that produces 200W with 1 mW drive. Paul On 08/19/2018 10:38 AM, ajparent1/KB1GMX wrote:
630m presents many issues for transmitters.? One is the ferrite |
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I have a U3S which is extremely useful on LF. I would not want to be
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without it! But a transceiver opens more doors. The major QSO mode on LF is JT9. Other considerations aside there is just no way to change messages quickly enough on a U3S. I built up a transmit converter to use with my FT-2000 for JT9 and CW QSOs. The 2000 is deaf as a post at LF so I use a Softrock Lite II (modified) as the receiver. The reality is if one wants TX and RX on LF/MF one must do some scratch building or spend a lot of money on limited (and often under-performing) commercial gear. It may be interesting to have a go at building a dual band LF/MF transverter for use with my upcoming QSX. :-) This would be best if the QSX is able to transmit out of ham bands, thinking 10.472-10.479 for MF, then one could use readily available and very stable 10 MHz oscillators. For LF it would be 10.135.7 to 10.137.8 which of course is no problem as it is in the 30 meter band. 73, Paul N1BUG On 08/19/2018 01:04 PM, KEN G4APB via Groups.Io wrote:
If you just want LF Tx, then the U3S will already do that. I have |
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There are pros and cons both ways. If a transceiver doesn't have a
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separate receive antenna input then you have to do the antenna switching between RX and TX. This is easy if the transceiver provides an external control signal on TX, but can be challenging if it doesn't. With a separate receiver no switching is required but changing frequency is not as easy and you may need overload protection on the receiver to prevent damage from RF while transmitting. So far I haven't destroyed any receiver front ends but the fact that measured isolation between my TX antenna and RX antenna is only 21 dB worries me! If you operate CW then yes a CW filter is extremely desirable. However the most common QSO mode on LF and MF is JT9. The most common beacon mode is WSPR. Under normal circumstances neither of these benefits from a narrow filter as the decoder does not need it. The exception would be if you have a very strong local station that you have to receive around. Virtually all of my LF and MF reception, including QSOs, has been done with 2500 Hz RX bandwidth but I don't have any locals on the bands yet. Paul On 08/19/2018 03:03 PM, ajparent1/KB1GMX wrote:
THer eare two things to consider... |
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Hi Tim,
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I completely agree with everything you said. We are in dire need of affordable, well performing kits for both bands! Some are not trying these bands due to the build from scratch and/or high cost aspects. Hans can speak for himself but I suspect for most kit makers these bands are a bit hard to justify compared to HF which is far more in demand. I consider myself very fortunate that the U3S supports these bands. Mine is happy cranking out WSPR on 2200m as I type. :-) 73, Paul N1BUG On 08/19/2018 06:14 PM, Tim wrote:
If no one makes a kit, or clear cogent instruction to modify existing |
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