Microlighters

Chaps this is aimed at farmers and security pilots..

This is very good for our farmer and security friends and may be really useful to many pilots..

Our Australian colleagues required a system to speak on both UHF 476 mhz and also Air band. No problem we have developed a twin system for them..however I acquired a Yaesu VX7r (similar to a Vertex Standard VXA710) and found a way to make it totally universal.

I have managed to obtain the following with it:

Transmit/receive on anything between 40mhz and 580mhz in any channel spacing that you require. That includes the entire Aviation band in AM and also commercial radio stations.

And obviously the entire UHF Australian CB frequencies. (That was easy).

So in short a security company/ farmer could use one radio and talk to farms, employees, airband and also to a crop sprayer..and listen to the cricket on Radio 2000. all in one (probably illegal) package. It will not go down to hf though. It delivers 1 watt in AM airband and 4 watts at 160mhz.

Took me a while to change the language from Japanese to English..

Take a look on the web Yaesu VX7 r, this may be of use..

Dont know about the antenna though..yet

Its radio interface is rather different to anything I have done before but I have got it operating on a intercom.

I see a farmer being able to use it as a universal hand held in the cockpit also.


Jabula Zulu1

Hi there,
I already had a look at the VX7 but didnt know its also transmitting on the Air Bands. Usually these Ham radio handhelds only receive.
I will certainly have a closer look at it.
Thanks for the info.
Joel
ON5XX

joel wrote:Hi there,
I already had a look at the VX7 but didnt know its also transmitting on the Air Bands. Usually these Ham radio handhelds only receive.
I will certainly have a closer look at it.
Thanks for the info.
Joel
ON5XX

I have one and it can be modified to transmit on the airbands BUT at very low output, only a few milliwatts.

This is mostly due to the filtering (hardware bandpass filter) on the transmitter output side that was never intended to pass airband transmissions. I am sure this can be modified but would involve heating up the soldering iron !

73, Rudi de ZS6DX/V51VE

Hi Rudi,
Yes that's what i was thinking as well. Yaesu used to have a real multiband handheld radio but I think they stopped to make it.
Not enough buyers I gues.
I see that

Whoops.....the previous message has been sent unfinished.
Rudi i see that you are quite a active Ham as well.
Maybe we will meet one day on the air.
I'm off to the Alps on Sunday for a week of trikeflying there. Here in Belgium the weather is not good enough and the country is too flat for some exitement.
73
Joel

joel wrote:Whoops.....the previous message has been sent unfinished.
Rudi i see that you are quite a active Ham as well.
Maybe we will meet one day on the air.
I'm off to the Alps on Sunday for a week of trikeflying there. Here in Belgium the weather is not good enough and the country is too flat for some exitement.
73
Joel

Hi Joel,

Yes, I have used the VX-7R on the airbands, around the flying field talking to planes in the circuit is fine but that is just about the limit. I see I have a couple of other radios (Mobil/base) that can also be used on the airbands with a mod or 2, I have tried the Yaesu FT-817ND, FT-857D and the FT-897, on these units the output is a lot higher but you start with a lot more. Looks like the Icom IC-746/756 family might also work. I want to put a FT-817 or FT-857D in a plane for some /am contacts, should be fun !

I used to be very active, not that active now but still on the air, waiting for the sunspots to return. I am a keen DX'er, mostly CW but also SSB and digital.

Hope to meet you on the air, will make a note of you call.

Enjoy the Alp flying, sounds stunning !

73,
Rudi

Ok on the 857. I have one here but didn't use it much yet. I was once playing with the idea to install it on my trike but it might be over the top .
I have a build in Filtzer radio for the Airband.
But the 857 might be great to try HF on the trike and I could put a 20m dipole in the wing. Well, that might be good on the really long flights but airtraffic is so dense here that I have to keep my mind on the flying most of the time.
I will send you the link to the pictures and story of our trip to the Alps soon.
73
Joel

The unit was the d2 series, the unit I modified transmitted 1 watt and was fine. Just remove all jumbers and reset. Worked well.

Zulu1

ZULU1 wrote:The unit was the d2 series, the unit I modified transmitted 1 watt and was fine. Just remove all jumbers and reset. Worked well.

Zulu1

Mine is also a d2 and the modification is the same (from mods.dk), I just had it on the digital watt meter and it produces 465mw UNMODULATED into a 50ohm dummyload. With full modulation it drops to about 280mw (This radio like most modern sets use "negative" modulation reducing the amplitude). It does radiate quite a few harmonics on this band due to the output filter not being tuned, when you measure power you must make sure you measure power on the MAIN frequency you are transmitting on and not the total output including all the other emissions. On the spectrum analyzer I can see that the spurious emissions are quite high and would contribute to a substantial amount of power if you measure them as well.

Using the provided rubber duck antenna (Short or extended) is quite inefficient, using a resonant antenna would help a lot. My first power measurement was done into the standard antenna and not into a dummy load thus giving an even lower reading.

So it is not actually that bad but still quite a few db down from a "real" aviation handheld. Because the output circuit is not optimized to transmit in the airband it is quite inefficient and generates quite a bit if heat as well.

I spoke to someone at Yaesu/Vertex (In JP) about a while ago about this and they explained the implications of the filtering, if you look at the circuit diagram you will see that different output filters are switched in for the different amateur bands but it has to use the closest (144-146mhz) filter for the airband.

Just one more thing I think I should mention......

Unless you hold an amateur radio license you can't buy or own this radio legally, using it in an aircraft would also have legal implications.

As far as the radio is concerned I think it is a stunning little unit and mine is used extensively and often under quite bad conditions and keeps going. I bought a second unit recently because the Softness kept on using mine !!

Regards,
Rudi