SS390 conversion to 10 metres

A forum for the discussion of matters of a technical nature. All such activities are undertaken at the readers discretion and own risk. If you don't know what you are doing, don't blame us if it all goes wrong!
Post Reply
User avatar
johnkyrle
Regular
Regular
Posts: 89
Joined: 25 Apr 2016, 20:24
Call Sign: 26TM3375
Location: South Gloucestershire
Contact:

SS390 conversion to 10 metres

Post by johnkyrle »

I have a SS3900 circa mid nineties and would like to convert it to operate on 10 metres.However,I would like to keep the CEPT (band c) and the rest of the high bands as is and convert the useless a and b band to operate on 10 metres.Is this a possibility?At the moment it will reach up to 28.305 on band f but totally useless as that spectrum of the band is only for date/c.w operation.
Anyone got any ideas? :wave:
User avatar
ROTEL240
Super Member
Super Member
Posts: 424
Joined: 01 Dec 2012, 20:10

Re: SS390 conversion to 10 metres

Post by ROTEL240 »

Send black spirit a pm if it can be done he is your man.
User avatar
MrWeetabix
Admin
Admin
Posts: 16340
Joined: 26 Aug 2008, 13:34
Call Sign: 26TM175
Location: Gateshead

Re: SS390 conversion to 10 metres

Post by MrWeetabix »

you might struggle with that..... logically, I;d imagine you'd have to have mids and Hi on A and B then the rest to go up-over from there..... but I'm not a rig doc.

Black Spirit will know the answer :-)
26TM175. OP: Craig. QTH: Gateshead IO94EW. Also 163TM175 when mobile in Wales 8)

Transmission1 on Facebook http://tinyurl.com/TM1onFB | Tango Mike on Facebook http://tinyurl.com/TangoMikeFB |
User avatar
Snake Plissken
Regular
Regular
Posts: 45
Joined: 01 Aug 2017, 13:47
Location: Escaped NY to Berkshire UK

Re: SS390 conversion to 10 metres

Post by Snake Plissken »

Hi John,

This can be done by fooling the binary adder IC's with the required N-code (usually achieved with a network of signal diodes)...

I have an old 148 GTL-DX Mk2 that does it this way; it uses an ancient JD Custom Multimode band converter EPROM...The EPROM is really just giving the UK 27/81 band with the correct frequency offset and no alpha channel gaps, the other bands are achieved by using the diode network method...

This radio covers LoLoLo/LoLo/Lo/Mid/Hi/HiHi/UK40, and then from 28Mhz up to around 29.6Mhz IIRC...some modification of the VCO circuit is required to achieve this, I've never experimented with the 3900's upper end capabilities so yours may go further...

If the lowest frequency band you want to keep is the CEPT one, I would guess you shouldn't have a problem getting up to 30Mhz....

As mentioned above, have a word with Nick Black Spirit! By reputation he will be the best source of advice on your options.... :thumbup:

Cheers,
Dan
Unidens (one or two)..
Cybernets (a few more)..
Stalker ST-9F DX Colonel FR360 Stag 357 Midland 79-900 Zodiac Tokyo Pegasus III Transceiver MkV
Cheiza CB702 workshop monitor :lol:
A few more, I forget...

Snake Plissken - Rescuing Presidents since a 1981 version of 1997 :D
User avatar
ch25
Top Poster
Top Poster
Posts: 1672
Joined: 03 Dec 2016, 11:07
Call Sign: Lemmy
Location: Poland

Re: SS390 conversion to 10 metres

Post by ch25 »

EPT3600 mod:
Connect together pin 13 and 15 of IC7 with a switch.
Radio will go up to 29.590
Done.
WE ARE MOTÖRHEAD, AND WE PLAY ROCK N' ROLL
You can't have too many antennas...
User avatar
johnkyrle
Regular
Regular
Posts: 89
Joined: 25 Apr 2016, 20:24
Call Sign: 26TM3375
Location: South Gloucestershire
Contact:

Re: SS390 conversion to 10 metres

Post by johnkyrle »

Thanks for all that guys.I was thinking of asking Nick as he did the re-alignment on this radio for me.ch25 is it really that easy?If so,how does the band selector operate after that mod?
User avatar
gmham
Top Poster
Top Poster
Posts: 2260
Joined: 13 Aug 2009, 11:27
Call Sign: 108TM154

Re: SS390 conversion to 10 metres

Post by gmham »

No rig doctor but would well imagine it's going to be deaf at either end ie you won't be able to have the best off both worlds. Personally would keep it standard and buy yourself one off the modern 26to 30mhz rigs.
Yaesu FTDX10
Kenwood TS711e
Anytone D578UV Pro+

Moxon antenna for 10/20 mtrs

——
John - 108TM154 / 108CO154
User avatar
slamjam
Radio Addict
Radio Addict
Posts: 749
Joined: 02 Nov 2010, 18:52
Call Sign: 26DT871
Location: Suffolk JO02

Re: SS390 conversion to 10 metres

Post by slamjam »

It can be done. My old 3900 was modded to go to 28.560 with a flick of a switch. It worked on band F only otherwise it was standard. The RX needed bringing up as was a bit deaf on the top end. The other way would be to swap the mixing crystal and lose ssl to gain ssh band. Which would take it to 28.755 much more useful than 25.615 ssl band.
26DT871 - Ipswich UK
User avatar
gmham
Top Poster
Top Poster
Posts: 2260
Joined: 13 Aug 2009, 11:27
Call Sign: 108TM154

Re: SS390 conversion to 10 metres

Post by gmham »

Yep not saying it cant be done all I am saying in my view its dont expect great rx performance at 29mhz + as well as on low 27mhz, its got to be set for peak either end not both.
had a cobra 148gtldx done as the chap above advised : quote " This can be done by fooling the binary adder IC's with the required N-code (usually achieved with a network of signal diodes)...
Yaesu FTDX10
Kenwood TS711e
Anytone D578UV Pro+

Moxon antenna for 10/20 mtrs

——
John - 108TM154 / 108CO154
User avatar
ch25
Top Poster
Top Poster
Posts: 1672
Joined: 03 Dec 2016, 11:07
Call Sign: Lemmy
Location: Poland

Re: SS390 conversion to 10 metres

Post by ch25 »

johnkyrle wrote:Thanks for all that guys.I was thinking of asking Nick as he did the re-alignment on this radio for me.ch25 is it really that easy?If so,how does the band selector operate after that mod?
It works as before, but last band ch40 will be 29.590MHz
WE ARE MOTÖRHEAD, AND WE PLAY ROCK N' ROLL
You can't have too many antennas...
User avatar
johnkyrle
Regular
Regular
Posts: 89
Joined: 25 Apr 2016, 20:24
Call Sign: 26TM3375
Location: South Gloucestershire
Contact:

Re: SS390 conversion to 10 metres

Post by johnkyrle »

gmham wrote:Yep not saying it cant be done all I am saying in my view its dont expect great rx performance at 29mhz + as well as on low 27mhz, its got to be set for peak either end not both.
had a cobra 148gtldx done as the chap above advised : quote " This can be done by fooling the binary adder IC's with the required N-code (usually achieved with a network of signal diodes)...
Not worried about the ssl's as no one is on there and it is a military frequency allocated 1st priority segment so pretty much a no go!!
Rather have it set up for the mids/highs and loose the useless lower part of the band
speeddemon

Re: SS390 conversion to 10 metres

Post by speeddemon »

:ugeek:
speeddemon

Re: SS390 conversion to 10 metres

Post by speeddemon »

:ugeek: :D :lol:
Post Reply