[hpsdr] Possible 5 band VHF transverter?

[Helmut, DC6NY]

Hi Conrad and Phil,

I’m afraid the even the MAX2870 is no good choice. A 5 band application 4m,
2m, 70 cm, 23 cm and 13 cm, requires LO-frequencies between 20 and 2400 MHz
assuming an IF covered by standard HPSDR. MAX 2870 datasheet shows phase
noise between -130 dBc/Hz and -100 dBc/Hz@ 10 kHz offset for these
frequencies. This is at least 20 dB worse than the traditional design using
a xtal-oscillator an multipliers and will reduce the TRV performance
dramatically.

73, Helmut, DC6NY

-----Ursprüngliche Nachricht-----
Von: hpsdr-bounces at lists.openhpsdr.org
[mailto:hpsdr-bounces at lists.openhpsdr.org] Im Auftrag von Phil Harman
Gesendet: Donnerstag, 14. März 2013 11:55
An: Conrad Farlow; hpsdr at openhpsdr.org
Betreff: Re: [hpsdr] Possible 5 band VHF transverter?

***** High Performance Software Defined Radio Discussion List *****

Hi Conrad,

You may like to consider the MAX2870 integrated VCO/Synth.  I've been 
evaluating one for the Cyclops Spectrum Analyser project and the phase noise

is quite good in comparison to other devices.

73 Phil....VK6APH



-----Original Message----- 
From: Conrad Farlow
Sent: Thursday, March 14, 2013 11:34 AM
To: hpsdr at openhpsdr.org
Subject: Re: [hpsdr] Possible 5 band VHF transverter?

***** High Performance Software Defined Radio Discussion List *****

I am working on a multiband transverter for Hermes, its early days but I
have narrowed down my choices of Silicon. It will be possible to lock to
either the 122.88 MHz Hermes oscillator or a 10 MHz ext source . It's a
synth but the phase noise is very reasonable for an integrated VCO/Synth
based design .

I had forgot about 220 MHz but there is no reason why it could not be
accommodated.

I hope that the transverter will work up to 13cms and down to 4M.

TX Output will be of the order of 23 dBm with some 10W amplifiers to
come later. This seems to be a sensible output power given the drive
requirements of a modern LDMOS devices.

I still have a LOT to sort out but so far I am very encouraged that I
can make this happen and that the transverter will be better than older
designs and will use modern devices that should have a long shelf life.

I will post some performance figures as I develop the boards, I expect
that it will take me 6 months or so to complete with my current workload.

73

Conrad G0RUZ



> ***** High Performance Software Defined Radio Discussion List *****
>
> This chip has been around for a couple of years, but this board might make

> a nice transverter for Hermes.  6 dBm out.  Too bad it won't reach down to

> 2M and 220.
>
> http://myriadrf.org/
>
> The Kickstarter Blade project would be more in line with this board, but 
> only has a 12 bit receiver.
>
> N0UU
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