[Premium-Rx] [harris-radio] Question on RF-590 filters
Peter Gottlieb
hpnpilot at gmail.com
Fri May 13 13:19:32 EDT 2016
Well, simply use the unfiltered 455 kHz IF output on the back. No radio mods needed. I have had mine hooked to a HP 3585A at times to make for a quick and dirty pan adapter.
Peter
> On May 13, 2016, at 12:34 PM, W2HX w2hx at w2hx.com [harris-radio] <harris-radio at yahoogroups.com> wrote:
>
> Thanks, Peter. Very interesting how this works. I wonder if the best solution would be to just bring the IF (before the filters) out to the back panel and use some kind of SDR/DSP receiver at the IF to handle all the filtering one might desire?
>
> I wonder the best way to accomplish this? One way would be to use the empty filter position and just bridge across it. Then set the dip switches to enable that position (called 20 kHz?). Or just remove the filter board completely and bridge across? I don't know if I might need a buffer stage or anything before an DSP receiver, probably not. Might need some attenuation, though.
>
> I wonder what the best approach would be the best approach?
> Eugene
>
> -----Original Message-----
> From: harris-radio at yahoogroups.com [mailto:harris-radio at yahoogroups.com]
> Sent: Thursday, May 12, 2016 10:09 PM
> To: harris-radio at yahoogroups.com
> Subject: Re: [harris-radio] Question on RF-590 filters
>
> The 590 is different from the 590A of which I have extensive knowledge of the firmware and peripheral setup. However, I strongly suspect many aspects of how the 590 works were repeated in the 590A. It's been a while and I could definitely refresh my knowledge but here is how it basically works.
>
> On the filter board there are two filter locations reserved for USB and LSB.
> I've seen 2.7 kHz and 3.2 kHz versions. 2.7 kHz might be better for voice reception in congested bands and 3.2 kHz works better for data waveforms which require more than the 2.7 kHz BW. I have 3.2 filters in my receiver and it has worked flawlessly on every voice channel waveform when other receivers had problems due to their narrower filters.
>
> The CPU board has a DIP switch which selects one of a number of preset known filter configurations. The filters are not in any way sensed by the firmware; rather, the firmware, for any given preset selected, enables the proper filter location (or locations, for ISB) and displays what it expects is there. So if you changed your 3.2 kHz filters to 2.7 kHz ones the radio would still display "3.2" for the BW when SSB is selected. Here is the filter configuration table in the latest code of the RF-590A:
> Filter DIP switch positions 1, 2, and 3 enable filter positions 7, 6, and 5
>
> Filter Position
> 1 2 3 4 5
> 6 7 8
> DIP Switch 4-8 ----- ----- ---- ---- ---- ----
> ----- -----
> 00000 3.20 3.20 0.30 1.00 3.20 6.00 16.00 20.00
> SSB SSB CW CW AM AM AM AM
> FSK FSK FSK
> FSK FM FM
>
> 00100 2.70 2.70 0.15 0.30 1.00 6.00 10.00 16.00
> SSB SSB CW CW CW CW CW AM
> CW CW FSK FSK FSK AM AM FM
> FSK
> FSK FSK FSK
>
> 01000 2.80 2.80 6.80 10.00 16.00
> SSB SSB AM AM AM
> FSK
> FSK FM
>
> 01001 3.20 3.20 0.30 1.00 3.20
> 6.80 16.00
> SSB SSB CW CW AM
> AM AM
> FSK FSK FSK
> FSK FM
>
> 10010 2.70 2.70 0.30 1.00 6.00 3.20 16.00
> SSB SSB CW CW AM AM AM
> FSK FSK FSK
> FSK FM
>
> 10011 2.70 2.70 0.30 0.15 1.00 6.00
> 3.20 16.00
> SSB SSB CW CW CW AM
> AM AM
> FSK FSK FSK FSK
> FSK FM
>
> 11001 5.00 5.00 0.30 1.00 3.20 6.00
> 10.00 16.00
> SSB SSB CW CW AM AM
> AM AM
> FSK FSK FSK FM
>
> 11110 2.80 2.80 0.30 1.00 3.20 6.80
> 10.00 16.00
> SSB SSB CW CW AM AM
> AM AM
> FSK FSK FSK
> FSK FM
>
> (Other) 2.80 2.80 0.30 1.00 3.20 6.00
> 10.00 16.00
> "Standard" SSB SSB CW CW AM AM AM AM
> FSK FSK FSK FSK
>
> I know the formatting isn't going to make it through but it's likely your firmware has different setups anyway. The point is that what is selected and displayed for each mode is in a relatively small set of presets that are selected through the BW selection DIP switch on the processor board. You can actually try different switch settings to see what presets are in your radio.
> It won't harm anything but do remember what your original switch setup was. I don't remember if the DIP switches were only read at startup so just in case if you change them, cycle power before seeing what happened. Btw, 20 kHz is IIRC the last slot and is used for wideband rear panel output mostly. As you noted it's not populated in your unit (neither is mine). ISTR there is a way to tell the processor it's not there but I don't remember what it is (maybe switch or jumper).
>
> Your radio has exactly the same filter complement as my 590A. The radio is not set up for multiple SSB BWs but I suppose it is possible with a combination of firmware and hardware hacks which are probably not worth the effort.
>
> To your questions:
> The filters with flatter phase response are better for data reception. I don't remember which one that is. I think they were an extra cost option.
>
> The extra slot is for the last filter for AM and FM, only for filter option 00000. It will claim 20 kHz but whatever you put there will be what you actually get. At least that's how my 590A is set up.
>
> I have heard there are some special firmware revisions for special purpose applications and I don't know precisely what the 590 is set up to do but hopefully this is a good start on understanding the way Harris set it up. I am not sure the 590A (and likely 590) can do SSB with more than one set of filters hardware-wise.
>
> Peter
>
> On 5/12/2016 9:59 AM, W2HX w2hx at w2hx.com [harris-radio] wrote:
> >
> > Hi friends,
> >
> > I just acquired an RF-590 (to replace the 590H I am selling on ebay).
> > One of the reasons I was interested in the 590 was that it has the
> > ability to have more than one filter per mode. The "H" has only one
> > filter per mode. When I plugged in the new 590 and tested it out, here are the filters it has:
> >
> > AM 6.0, 3.2, 16
> >
> > SSB 3.2
> >
> > FM 16
> >
> > CW 1.0, .3
> >
> > I was surprised that I had only one bandwidth for sideband. I would
> > have expected some choice here. I then remembered that I had purchased
> > a spare filter board a long time ago. So I dug it out and took a look.
> > This is what I found. The 590 seems to have mechanical filters, but
> > this spare board I acquired seems to have crystal filters. Here are some pictures:
> >
> > http://w2hx.com/x/Harris/RF-590/0511162325.jpg
> >
> > http://w2hx.com/x/Harris/RF-590/0511162325a.jpg
> >
> > Can anyone tell me a few things?
> >
> > 1.When/why/how did Harris have different options for filter technology
> > (crystal/mechanical)
> >
> > 2.I noticed that both boards seem to have a spare "space" for a
> > filter. Can I put a filter into one of these spots?
> >
> > 3.If I were to add a filter, how would I know which mode would "see"
> > that filter as available?
> >
> > Does anyone have a 590 with more than one BW for ssb? I would love to
> > try to use one of the 2.7k filters from the crystal filter board
> > pictured above. But I wonder if I would need two filter slots not just one to handle USB and LSB?
> >
> > Maybe I would have to replace both 3.2K filters with the two 2.7k
> > filters? If I did that, would the display show the right bandwidth
> > automatically or is there something I would need to do?
> >
> > I know mechanical filters have very steep skirts. But for general
> > purposes hamming, might the crystals sound better than the
> > mechanicals? Anyone ever play with these two types of filters in a 590?
> >
> > What can you guys tell me about filters, filter boards, the 590 and all of that?
> >
> > Thanks in advance!!
> >
> > Eugene W2HX
> >
> >
>
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