[NLRS] VHF Field Day modes

[Dr. Gerald N. Johnson]

Not all rigs need or work sell with the transformer isolated I/O. The 
TS-450, FT857, and FT 897 have true line level in and out and work 
better with a simple cable between the sound card and the radio data 
jack than with a Rig Blaster supposedly made for the radio. The Rig 
Blaster has lots of distortion on receive while the line level cable 
does not. These Yaesus also have digital VOX so there's no need for 
keying, so long as the software turns the transmit tone on and off.

FLdigi is good, runs in linux, puppy linux (that can boot from a CD or 
maybe even a floppy), and windoze.

While PSK-31 has some benefits, local reports on HF are that the few 
digital FD contacts were more often on RTTY but the CW stations made 
more contacts at a higher rate than the digital stations. Running CW, 
digital, and SSB on the same band at the same time and site usually is a 
disaster from receiver overload. Not that the receiver is damaged, just 
it can't hear when another local rig is transmitting in the same band.

73, Jerry, K0CQ

On 6/16/2013 12:16 PM, Doug Reed wrote:
>
>
> One thing you should note about the FD rules is that voice, CW, and
> digital are all considered separate band-modes and provide a way to
> multiply your QSO points when station count is limited. Instead of
> working a station just once per band, you can work them in 2 or 3
> modes per band for up to 5x the points.
>
> If your club is going to the trouble of running a VHF station,
> consider adding a computer and sound card interface to that station.
> You get one point for the voice contact, 2 more points for a CW
> contact with the same station, and 2 more points if you can contact
> them on a digital mode as well. Having the sound card interface also
> sets you up to try meteor scatter mode which could increase you points
> score when the band is otherwise dead...
>
> So if you can operate all three modes, you could actually improve your
> VHF point score 5X by making duplicate QSOs in alternate modes on the
> same band. This is a perfect excuse for the VHF emergency services
> crowd to use the FLDIGI software for real. I know that FLDIGI has all
> the digital weak signal modes that you could want and you can
> send-receive CW with it as well. Or you could use any other digital
> sound card program you want.
>
> There is also nothing that says you have to QSY to use the other
> modes. CW and digital modes are OK anywhere in the band. So you could
> call CQ on your frequency and mode of choice, and after the first Q is
> made, ask if the other station has CW or digital modes and make those
> Q's before you offer to QSY. Do the same on each band where you have
> common equipment. You may find that CW or digital lets you make some
> Q's you couldn't have made on SSB. I suggested PSK31 because it can go
> 14dB below the noise, WSJT can dig 24dB into the noise...
>
> One nice thing about doing the sound card modes is that you never have
> to leave SSB mode on the radio if the computer is doing the sending
> via the sound card interface. And of course you can pre-load various
> FD messages to automate the digital and CW Q's even more. I don't
> think FLDIGI has a SSB voice keyer mode, too bad....
>
> If you are going to do this, you might want to amend your listing in
> the VHF-Blog to indicate CW and digital capability. I'd suggest
> keeping your options to a minimum, perhaps just CW and PSK31 if on SSB
> or CW and MFSK16 on FM? (It never made much sense to use CW or digital
> with an FM voice rig, but it does meet the requirements of the FD
> rules and it is FCC legal....)
>
> Just be sure to reduce the digital audio drive levels to keep power
> output low so you don't overheat your finals!!! Digital modes are
> considered 100% duty cycle and most SSB rigs can't do that at full
> power output. It is probably less of a problem with FD Q's since they
> are short and fast, but don't blame me if you damage your finals
> running too much power.....
>
> I'm not expecting anyone to do this if 6M is open and hot. But in the
> more likely case that the bands are quiet, this does offer you a way
> to increase your VHF QSO points with a fairly simple station upgrade.
>
> The most difficult part of this is getting the sound card interface
> and a computer with software before next Saturday. Having a little
> time to play and become familiar with the software would be a good
> thing as well.... Radio City would be happy to sell you an interface,
> they usually have them on the shelf. My personal favorite is the
> Signalink USB because it is one cable to the computer and one cable to
> the rig, but YMMV.
>
> If anyone would like to build their own sound card interface for next
> year, let me know. The main ingredient is two 600 ohm transformers and
> some sort of isolated PTT keying circuit, and I can provide those to
> anyone who wants to build the rest. I'm considering trying the KH6TY
> interface (March 2011 QST) with a USB dongle as my next interface,
> although K0BXB had an interesting suggestion in June 2011 QST....
> <https://sites.google.com/site/kh6tyinterface/>
>
> 73, Doug Reed, N0NAS.
> ______________________________________________________________
>