[VHFcontesting] Transverter for 446 FM

[Bill Rogers - K2TER]

Terry,

That's a fantastic suggestion. Thanks!  I hadn't thought to look at the
ApolLO. 435-26 seems to be the right documented setting, as you stated. That
would place the IF at 37 for 446.  I wonder if there are undocumented jumper
settings to get it closer to 28.  Once I have an LO solution that works I
can select a transverter to "translate" up filterwise.  Older DEMIs with
interdigital filters can be tweaked and of course the cans can be retuned in
the newer ones. 

Looks like you are solving for FM integration in an interesting way.  Sounds
like it's perfect for the equipment you have.  Since I have everything but
446 integrated I was considering a fall back to automatically switching the
headphones and mic to the FM rig (FT736R) when I selected the band in the
SDR UI. Maybe it'll come to that but for now I'm pursuing the xvtr path.

73 and Happy Holidays!
Bill
K2TER

 





 

-----Original Message-----
From: Terry Price [mailto:w8zn54 at verizon.net] 
Sent: Friday, December 23, 2016 8:24 AM
To: 'Bill Rogers - K2TER' <k2ter at rochester.rr.com>;
VHFcontesting at contesting.com
Subject: RE: [VHFcontesting] Transverter for 446 FM

I would seriously consider a VHF ApolLO from DEMI, it gives you many
variations to play with to find one where there are no birdies. Using the LO
scheme of 435 - 26, 27, 28, 29 would put 446 at 47, 48, 49 or 50 MHz. I
think the problem you are going to have is the Diplexer in the output of the
mixer on the IF side of the transverter. I don't think it will pass
frequencies that high. A quick call to Steve at DEMI would be in order. What
you need is an LO at 104.5 (then X4 = 418 + 28 = 446) which would put 446 at
28 MHz but getting right on an even boundary is always asking for problems
with birdies. Since most SDR's and software allow for frequency offsets,
pick a weird LO that brings 446 to a non-boundary frequency and let the
software do the rest.

What Andy and I are doing for FM is to use something like a IC7000 or
706MKIIG with a 222 transverter off the 10m spigot to cover 6-446 FM. Using
N1MM, we set one of the stations for SO2R with our K3 as radio 1 and the FM
rig as radio 2. Then by just toggling back and forth, the logging captures
the right frequency and mode and since N1MM can switch audio and PTT lines,
it works out VERY nicely. We combine receive audio by just using the speaker
output from both radios through isolation resistors (I use 50 ohm 2w carbon
resistors) and Y them together.

Good luck, happy holidays and catch you all in January.

Terry - W8ZN
K8GP/R

-----Original Message-----
From: VHFcontesting [mailto:vhfcontesting-bounces at contesting.com] On Behalf
Of Bill Rogers - K2TER
Sent: Friday, December 23, 2016 7:46 AM
To: VHFcontesting at contesting.com
Subject: [VHFcontesting] Transverter for 446 FM

Season's Greeting!

I am completing integration of ANAN-10's SDR as IF rigs for my rover. I have
to say I am quite happy with the simplified and integrated operating
experience for contesting this arrangement provides for our two operator
station with all transverters from 144-10G. So much so that I have added
provision to run FM with separate transverters that are available through
the same interface.  

The sticking point for me at the moment is 446 FM. I tried to re-crystal a
DEM transverter to give me 446 at 30 MHz but when I hooked it up to the SDR
I found there was a spur right on 30 - unusable. I could continue down that
path with another rock but before I do I figured I'd ask the question here.

Does anyone have suggestion/experience on how to get 446.000 from a 70cm
transverter?  I do have the option to go 42 MHz on the IF, if the
transverter filters would allow. 

Thanks and 73,
Bill
K2TER




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