Fw: [Premium-Rx] Wanted: Eddystone 1650 HF/LF Receiver

[Michael O'Beirne]

Hi guys

I have the original version of the Eddystone 1650 and what follows may 
influence potential buyers of this set and the 1650/6.  Mine was obtained in 
brand new condition.

The tuning is excellent and smooth with a weighted knob and the panel has 
big bright LEDs.  The image and IF rejection is excellent.  The crystal 
filters are excellent too and, unlike many other manufacturers, are relay 
switched, so there are no IM problems from steering diodes.

It delivers stunning AM quality through the use of the excellent Plessey 
synchro demodulator chip.

There is no obvious synthesiser phase noise.  It's a nice quiet receiver.

However, the AGC on SSB has a serious problem (at least in my view).  The 
first syllable is clipped because the attack time is far too long, at about 
50mS.  Chris Lorek mentions this in his detailed review of the 1650 in "Ham 
Radio Today" (now defunct) August 1987.  I know of no mods to shorten the 
attack time to a more acceptable 5 - 10mS.

I took this AGC issue up in the Eddystone User Group newsletter, and the 
designer responded saying that this time constant was a GPO/maritime spec. 
That may well be so, but in my view that was no reason for what I thought 
was a poor engineering design.

Users of all the 1650s also complain about the front panel membrane 
keyboard.  It is nearly identical to that on an office coffee machine.  It 
delivers a poor tactile response.

My set has problems with its expensive frequency reference standard.  These 
were made by Cathodeon, who ceased trading a long time back.  Unfortunately 
the standard's output is at at 5.6 MHz, four times the IF).  If it had been 
at 10MHz it would not have been too hard to fit a 10MHz standard from 
another manufacturer or apply the output from an external standard.

I regret to report that all the Cathodeon frequency standards I have here 
have either failed or cannot be pulled back on frequency because of 
excessive drift.  My replacement from Eddystone cost around £300 and that 
too has now drifted beyond the limit of the trimmer.

The last address I have for Geoff Steedman, M0BGS, was 5 Allerton Grange 
Gardens, Chapel Allerton, Leeds, LS17 6LL, tel (in the UK) 0113 269 6527.  I 
had a few phone conversations with him on the conversion of the 1650/6 and 
he was the epitome of technical helpfulness.

73s
Michael O'Beirne
G8MOB





----- Original Message ----- 
From: <GandalfG8 at aol.com>
To: <premium-rx at mailman.qth.net>
Sent: Sunday, September 02, 2007 7:08 PM
Subject: Re: [Premium-Rx] Wanted: Eddystone 1650 HF/LF Receiver


>
> In a message dated 02/09/2007 16:49:12 GMT Daylight Time,
> w4nj at tampabay.rr.com writes:
>
> Additionally, if anyone has any comprehensive info on converting the 
> 1650/6
> Remote version for local use, adding VFO, speaker etc, I'd love to hear 
> from
> you!
>
>
>
> -----------------------------------
>
> Hi Cliff
>
> Geoff  Steedman in the UK was modifying these sets a few years back and 
> did
> provide  comprehensive notes at one time. I also recall parts, including 
> the
> VFO encoder, being available from somebody in  Holland.
> Unfortunately, I can't find contact details for  either right now and the
> printed notes that I had from Geoff are buried  somewhere in storage.
>
> Whilst the 1650/6  could be, and probably still can be, had much more 
> cheaply
> than a "proper"  version, there's a fair bit of conversion work involved 
> and
> the end  result will never match something like the  1650/9.
>
> Although provision of variable tuning is not too  difficult, I'm pretty 
> sure
> it's only the rotary encoder that's  lacking, it's not just the obvious 
> things
> such as VFO and speaker that need  sorting,
> New  firmware is required , and there's some significant issues with IF
> filtering and demodulation.
> For example  there's only two crystal filters and no space for more, 
> neither
> on the PCB nor  on the membrane switch front panel, which leaves you with
> bandwidths of 3,  8, or 16 KHz, the latter being from the roofing  filter.
> There also seems  to be some form of mod required to enable AM/SSB 
> switching,
> even  though the switch positions are already included on the  panel.
> Some of the  normally fitted rear panel connectors are also missing on the
> 1650/6.
>
> I've got some  internal and external photos of a couple of 1650/6s, one
> modified and  one not, and also some of a  1650/9.
> I can email these  to you if you'd like to compare  them.
>
> As to the  "proper" sets, I prefer the 1650 to the Racal 1792 from the 
> same
> period, but my experience has just been of the 1650/9, the first that had
> BITE fitted, so I can't really comment on the earlier  versions.
> Just as with the  1792 though, CPU battery corrosion can be an issue but 
> it's
> less easy to spot on  the 1650 as the CPU board is under a cover behind 
> the
> front  panel.
>
> If you can find  one with the optional motorised preselctor fitted that 
> would
> be one heck of  a bonus.
> I have seen them  but they seem to very rare  indeed.
>
> regards
>
> Nigel
> GM8PZR
>
>
>
>
>
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