[hpsdr] Possible 5 band VHF transverter?
Dick Faust
k9ivb at cox.net
Fri Mar 15 18:27:17 PDT 2013
Fortunately, or unfortunately, I already know that it is not yet
possible to use Hermes signal sources for external PLL synthesizer.
What I was looking for is the proposed method to be considered to
actually use those signals.
Dick K9IVB
Helmut, DC6NY wrote:
> 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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>>
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