Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KC8GRP, Aug 28, 2014.
Wow, that is something to look forward to.
I found one advantage (I'm not sure for who though) of having a radio with 6 meters and 2 meters (I have a Icom 746 Pro and Icom 7600, both have 6 meters)... it got me to try a band that I had never tried before and probably would not have bought a radio just for 6 meters. By getting me to try it, I ended up buying antennas and other things with the idea of transmitting and receiving better. Because the 746 Pro has 2 meters, I find that I can get back on 2 meter SSB again (I use to have a all mode 2 meter radio back in the 80's and used it for SSB and simplex) and have actually been cruising the repeater frequencies more... resulting in my getting more 2 meter antennas for both SSB and FM, vertical and horizontal, that I probably wouldn't have got for just the 2 meter FM only mobile radio I have. So getting a radio that has both HF and UHF/VHF may not be all that convenient if you want to monitor HF and UHF/VHF, it does get more people to try bands that they might not other wise try. I'd like to try one of the higher VHF bands but I probably won't buy a radio just so I can try it but if it was in one of my radios I would give it a try.
In the long run, I still prefer HF and though I'm losing interest in 6 meters (and it's not because the band is dead either) I still am interested in 2 meter SSB and FM simplex. I think it's because 2 meters still has locals that will talk on that band, even when the band is dead where 6 meters is almost exclusively only used when the band is open for some distance... at least that is what I'm finding on 6 meters so far.
Methinks you and I have similar thoughts on all this, Mike.
I saw a Kenwood 10w 2 meter all bander on the marketplace yesterday. I was sore tempted by it. I have three different 2m FM mobiles that I do not use . That older Kenwood might be fun, but I can't justify the cash out when I have three in a box. Maybe someday I will off those rigs and look into something that will let me dabble in 2m sideband as well as FM smpx. It won't be a DC to daylight box. BTDT
TOM K8ERV Montrose Colo
Obviously that requires a computer and software to operate, but will also require external PAs for the various bands since it runs very low power, not enough to be really usable except perhaps on HF where propagation does a lot of the work. With a single antenna port, this would also require an outboard switching system to select the proper amplifier/antenna combination for each VHF or UHF band. A 10W linear PA for 902 or 1296 MHz can easily cost $250-$300 each; for 432 or 222 MHz, a bit less. Switches or relays to enable the bandswitching might cost a couple of hundred dollars.
So, one would likely end up with the SDR transceiver box; a computer (maybe a laptop); and perhaps 5-6 external amplifiers and a method to switch them, to form a functional station. In EU it might be easier as stuff's closer together (even countries), but here in the U.S., if you don't have a working radius of a few hundred miles, contacts can be very hard to come by.
What happens to the 80m band or the 23cm band on a DC to Daylight SDR when there's a 1500 microvolt signal at 27Mhz?
I have a FT857d and have to do that, jump back and forth all of the time.
Paying attention to a spotting site helps and I will usually call CQ around dusk as well, since that seems to be when I hear activity most around here.
But I'm sure I am missing some openings. I do my best to go check every once in a while, especially if there isn't a lot going on with the HF side.
I'm responsible for the design of the Cross Country Wireless Sentry transceiver. In the Sentry transceiver there are some high performance bandpass filters in front of the receiver. 80m or 23cm wouldn't be affected by a big signal on 27 MHz.
In the receiver the RF amplifier is a E-pHEMT device with the LTC5584 demodulator mixing down to a near zero IF. Using it in the RSGB Tuesday night activity contests from the busiest locator square in England I typically have over 25 contest stations in line of sight and I don't see any overload operating the prototype on 50, 70 or 144 MHz.
By the way we are planning to update the web site next week with the latest information.
Chris, maybe you can answer some questions to which I didn't see obvious answers reading the prelim data sheet:
How much output power from the TX on each band?
Does the rig provide bandswitch data output (like a pull-down) for each band, to help activate external relays to engage power amplifiers for the various bands?
These days it's possible to cover 20MHz to several GHz in a single 20W broadband PA with very good efficiency for FM/CW use. At some point this technology will become viable for ham use. I've designed quite a few ultra broadband PAs using SiC and GaN technology but these were not for consumer use.
However, I'd expect that one headache/dilemma for single radio, multi hamband use up at VHF/UHF would be the need to support multiple aerials (with multiple aerial ports) if high performance was required on every band.