Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KB2E, Jul 31, 2019.
Wonder if there might be a setting to tell it to remember the power setting or not?
I would never trust that.
These transverters can be nearly bulletproof if used with rigs that have a specific "transverter output" port, where the mex output is 50mW or 100mW or something. Lots of rigs have this feature. It's an output that taps into the driver stage, way before the final amplifier. Even my old TS-830S (c. 1984 or so) had that.
That's why I'm using a TS-430 as a transverter driver. I wish it had >1 memory for split operation though
Nope! Nor would I. That's why I used a checklist. The XVTR was on because when it is left on 24/7 it is more stable as far as drift goes. Check lists will not fail you. I also use "habit" to keep my equipment working. WHen I change bands on the XCVR I ALWAYS touch the OP/STBY switch on the amp. It's just a habit I developed purposely. I'll never have an amp on one frequency and the rig on another (like my buddy has TWICE and blown up his amp twice and the rig one) and I'll never overdrive the amp IF the 7300 remembers that the band I swicthed to was 100 watts when last used.
The 7300 is a great rig but it is missing a couple very basic features that would be handy and with the nature of the beast the XVTR port could be programmable from 50mW to say 10 watts. They might be able to do it in software but I'd not depend on Icom to do anything much more with the 7300 except support what the features they already have in the firmware upgrades. There is already rumor of a 730x with a couple extra features lacking on the 7300 and of course priced way below the 7610. Some investigation shows that there's "room" to add in the firmware of the 7300. So since there is no port they could (if possible) make an option for default band power levels. In the case of the XVTR in question you could set 10 to 5 watts default on any switch. So even if you raised it to 100 if you swicth out of it the next time you enter 10 meters it would be 5 watts. There's still room for disaster though sinc eif you raised the power you'd hav eto remember to lower it or switch away from 10 after which the radio would take the power down the next time you used 10.
Btw - this is why I used the TS-430 - the transverter output is almost exactly what I need.
However (!), the ALC needs to be provided by the transverter. This isn't a huge deal for CW, SSB and maybe AM if you're careful not to overdrive things, but on FM the TS-430 FM board puts out /full power/ on the TX side into the TX path and expects ALC feedback to bias it back down to a sensible level. There's no FM power control available - in the normal config it's always 100W.
So without ALC feedback from the transverter it always ends up outputting garbage.
I really should write up a blog post about this as I think it's a good thing to know if you're intending to interface some older radios to transverters.
I mention it here because I'd hate to find that the ALC 'jump' that icoms have had in the past during initial key down happen when you're using a transverter. These ukranian transverters get angry with 0.1W on the input side and will go pop. If your transverter port is getting ALC feedback from inside the rig but it initially exceeds 100mW, pop.
The old TS-830S didn't have that issue.
If you used the XVTR output, it was unregulated by ALC but very low-level, always; however I've never used a transverter for FM on the VHF bands. I have used them for FM on the microwave frequencies, but those are DEMI transverters with external attenuators so they can't be overdriven.
VHF-UHF FM rigs are so cheap and have a billion memories and all that.
oh i know, i can buy an FM 220MHz radio but then I wouldn't have learnt anything!
oh and to be clear - it puts out full pre-finals drive, not an adjustable level tx drive. It's NOT putting out 100w RF to the transverter.
The RF/carrier knob is not used at all in FM mode; it modulates a signal thats about 5x stronger than needed for linear operation of the transverter.
Yeah, got that.
The TS-830S is a better "transverter" rig, but doesn't even include FM.
I agree about the "learning" part.
Nothing is as educational as failing. When you do something that works immediately, that's not as educational.
oh yeah, it's been educational. I built a little PL tone generator for the TS-430 so I can use it on FM repeaters. It works well enough now that I'm thinking of making up a little kit for it and putting it online.