[hpsdr] Possible 5 band VHF transverter?
Helmut, DC6NY
dc6ny at gmx.de
Fri Mar 15 14:19:53 PDT 2013
Hi Dick,
Hermes does not provide additional PLL capability yet, but it is possible to use Hermes signal sources as reference for external PLL synthesizer.
73, Helmut, DC6NY
-----Ursprüngliche Nachricht-----
Von: hpsdr-bounces at lists.openhpsdr.org [mailto:hpsdr-bounces at lists.openhpsdr.org] Im Auftrag von Dick Faust
Gesendet: Freitag, 15. März 2013 21:00
Cc: hpsdr at lists.openhpsdr.org
Betreff: Re: [hpsdr] Possible 5 band VHF transverter?
***** High Performance Software Defined Radio Discussion List *****
Hi
Would someone, briefly, outline how and where you can get the phase lock
signals from Hermes. The Atlas Bus boards are more obvious.
Thanks
Dick K9IVB
Helmut, DC6NY wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi,
>
> Kjell, basically you are absolutely right. The AD9915 would be really fine, but very expensive (USD 108.--) and an 88-lead LFCSP package. On the other hand I also think it’s better to use PLLs locked to Hermes and no other independent signal source.
>
> 73, Helmut, DC6NY
>
> -----Ursprüngliche Nachricht-----
> Von: hpsdr-bounces at lists.openhpsdr.org [mailto:hpsdr-bounces at lists.openhpsdr.org] Im Auftrag von Kjell Karlsen
> Gesendet: Freitag, 15. März 2013 09:50
> An: hpsdr at lists.openhpsdr.org
> Betreff: Re: [hpsdr] Possible 5 band VHF transverter?
>
> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi All.
>
> Why not consider using a DDS to generate the LO in a transverter? AD has
> many new chips that may be used. I know they may have some spurs but AD
> has described some methods to reduce them.
>
> 73, Kjell
>
>
>
>
>
>
> På Fri, 15 Mar 2013 09:14:50 +0100, skrev Helmut, DC6NY <dc6ny at gmx.de>:
>
>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> Yes Conrad, I understand your plans, but it’s a pity to see Hermes
>> performance decreasing, hi.
>> You know these broadband VCOs produce terrible phase noise due to low Q
>> circuitry. After division by 64 or 128 PN gets acceptable on low
>> frequencies. Perhaps you can use that method for 4m/2m/70cm and external
>> small band VCOs beyond 1 GHz. Good luck!
>>
>> 73, Helmut, DC6NY
>>
>> -----Ursprüngliche Nachricht-----
>> Von: hpsdr-bounces at lists.openhpsdr.org
>> [mailto:hpsdr-bounces at lists.openhpsdr.org] Im Auftrag von Conrad Farlow
>> Gesendet: Freitag, 15. März 2013 01:19
>> An: hpsdr at openhpsdr.org
>> Betreff: Re: [hpsdr] Possible 5 band VHF transverter?
>>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> I agree Helmut this approach will not be as good as a well designed 3rd
>> overtone oscillator in the VHF region, however it will be acceptable.
>> This transverter is a multiband device that will be much cheaper and
>> smaller than the traditional topologies. It is not designed for a
>> contest station on 2m on a hill top.
>>
>> The MAX2870 is not the device that I have in mind but the performance is
>> only a little better.
>>
>> A low phase noise super linear transverter is a different exercise and
>> one that I am really interested in tackling as well, but later.
>>
>> Despite that when coupled with Hermes it will be much better than the
>> typical VHF radio and rather better than the run of the mill transverter
>> designs that are out there. Not all Xtal oscillators are made equal.
>>
>> However at this stage until I have done more testing and looked at the
>> reality of the spurs from the device and therefore the filter
>> requirements I am not prepared to share a block diagram.... yet. When I
>> have the building blocks in place and have tested them - and I have some
>> performance figures I will of course be prepared to share.
>>
>> Can I just ask again (as I do not have a Hermes yet) is high side
>> injection feasible with PowerSDR? On 70 MHz I would like to use high
>> side injection. My LO frequency range with the proposed device is 85 -
>> 2700 MHz.
>>
>> I am chiefly interested in weak signal modes such as EME and close in
>> phase noise is not that important to me, I don't have any truly strong
>> signals above 50 MHz locally. I do have some stations who are quite
>> strong and clearly have their own phase noise issues :) Improving things
>> my end won't make any difference with those guys; fortunately they go to
>> bed early.
>>
>> If any one has any ideas for a multiband transverter that can achieve
>> -146 dBc @ 10 kHz I'd love to hear your ideas.
>>
>> So to summarise, my design as it stands will degrade Hermes by up to 20
>> dB/Hz @ 10 kHz offsets above 432 MHz however it will be a Hermes sized
>> box that will do at least 5 bands. When I know that it will work I will
>> publish a block diagram and ultimately construction details, pcbs etc.
>>
>> For the best strong signal handling mono band transverters with LO based
>> upon a Xtal still wins out from what I have seen so far, I just fancied
>> doing something a bit different.
>>
>> Whatever I do its got to be better than the awful Icom IC910 that we
>> have at our radio club!
>>
>> 73
>>
>> Conrad G0RUZ
>>
>>
>>> 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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