So to make a long story short, I found three things to be true:
(1) My brand-new DSO needs a trip to the cal lab. (big surprise)
(2) My 5000A's transverter *output* appears to be flat to within 1 dB
(measured 0.9 dB) from 28-32 mHz
(3) It's too late and tired out to play with the receiver tonight.
So -
Assuming the transverter input holds up as well as the output does, then
the 5000A itself will work fine.
I also found that with the exception of the old Yaesu "FTV-XXX"
(bandswitched) designs and perhaps a few others, transverters are
basically designed to cover the CW/SSB/DX parts of the band(s) only.
That makes sense, since the more narrow you make the receiver, the
better it can be made to perform.
Perhaps two switched helical filters instead of one fixed one?
Interesting exercise, anyway.
73,
Jim N7CXI
On 11/28/2012 11:06 PM, Jim Barber wrote:
Hi Bill, thanks for the reply.
I don't have anything that will measure power accurately those levels,
but my 100mHz DSO should have relatively constant gain across that
narrow a spread, and I can certainly measure RF voltage into a 50-ohm
load. If I get time in the next couple of days I'll build a 50-ohm
scope tap/load with a BNC on it and see what happens. The 5000A
transverter RX is easier. I have a WaveTek generator with a fairly
recent cal - I can sweep 28-32mHz at 50uV (or perhaps less to make
sure the AGC stays out of it) and again see what happens.
I'm not looking for trouble here - it just seems like a reasonable
application for the 5000A, or perhaps the 1500. I haven't actually
*used* 2M or 70cM FM in a couple of years now, but since I'm looking
into it, why not go for it all?
73,
Jim N7CXI
On 11/28/2012 10:15 PM, Bill Bordy, NJ1H wrote:
Jim,
I am using an old Downeast Microwave 2 meter transceiver with my
Flex-5000A using the Flex XCVR 10 meter IF connections. I have a pretty
severe roll off on TX output from the transceiver in the satellite
portion of 2 meters. At this point, I don't know if it is the
transceiver or the 10M IF output. I am able to use the satellite 2M
transmit frequencies, 145.8 to 146 MHz, but the output from the
transceiver is nowhere near the 25W I can get at 144.200 MHz.
The transceiver appears to be optimized for 144.2 MHz.
I operate full duplex on the satellites and my audio quality sounds
fine.
I have transmitted above 146 MHz on the inputs of some FM repeaters. The
roll off of the TX output is of course worst the higher in frequency I
go. This is a low priority item for me, as I have 2M FM gear and rarely
use it.
I am using PowerSDR v2.4.4.
I need to characterize the 10M IF output power from 28 to 32 MHz to see
how flat it is. If someone has done this or has the right equipment to
measure easily, that would be great.
73,
Bill
NJ1H
On 11/28/2012 10:57 PM, Jim Barber wrote:
I read in the release notes for PSDR 2.4.4 that:
"12. Improved FLEX-5000 Transverter Operation. Band edge checking for
the transverter IF has been relaxed, allowing out of ham band IF
transmit on the transverter TX port. Also the 10m IF TX filter switch
point has been moved to 32 MHz to allow for a wider IF transmit
capabilities."
Relaxed to what, and what is the practical upper limit? I saw where
someone else asked this, but didn't find where it had been answered.
My reason for asking is that I'd like to be able to use my 5000A with
a transverter to cover the entire 2M band all-mode. Is that feasible?
The radio transverter port(s) would need to work to 32 mHz with
*reasonable* gain flatness, and I'd have to find a transverter that
would cover the whole 4 mHz as well. Has anyone accomplished this and
have it working? If so, what transverter are you using? I could go
ferret most of this out on my own, but I'd like to know what limits
the company intends to support, so I don't end up with a hole in my
foot when PSDR is updated.
Then the last question is if I decide to offload the VHF/UHF ops to a
Flex 1500, are the rules and requirements different?
So many questions... ;-)
Thanks,
Jim N7CXI
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