[MAMS] PLL

Thu Jan 6 22:51:21 EST 2011

Hi Jerry and all

At the last Central States I picked up some Harris transmitter ans 
receiverseparate boards with a service manual , I can get the model #s if any 
one cares.
I think they were 2.xx GHZ systems for a phone repeater I think 1980's stuff the 
price was right so I just bought it not thinking .
They are well made as some one said and there are arrows and lines telling the 
path of RF through the component systems.

Mike
N0obi
73

________________________________
From: Dr. Gerald N. Johnson <geraldj at weather.net>
To: maryboller <w9obg at yahoo.com>
Cc: Mid-America Microwave Society <mams at mailman.qth.net>
Sent: Thu, January 6, 2011 1:35:19 PM
Subject: Re: [MAMS] PLL

I'd be inclined to compare it to the FW published schematics and work 
from there.

I helped the micro LO in my 10G transverter by stuffing all the foam 
(Dow blue board) bits I could get around the crystal, then I cut the IF 
drive as much as I could (without taking the TC board out and changing 
its fixed attenuation) to cut the heat to the transverter box and so to 
the crystal. Working rovers from Buck Hill at MSP the second weekend of 
10G+ 2009 I had to chase them all around, some moved a couple KHz each 
transmission but the locals on the hill though I wasn't moving an 
unreasonable amount.

-20 comes from telephone central offices where -48 is the supply standard.

73, Jerry, K0CQ

On 1/6/2011 1:06 PM, maryboller wrote:
> Many thanks for the info. I have a pretty good rig on 5760 right now,but
> it still has the DEMImicroloc and the only problem with that is finding
> me on the dial while the thing settles down. YOu are right about the
> minus twenty I got a 1.5 watt Harris amp from the same guy to better
> drive my Spectrian strip. The minus sign was now clearly printed and I
> learned very quickly. Didn't do any damage and with minus 20 it works
> great. Wouldn't happen to know where a guy could latch on to a print of
> the pll???
>
> ------------------------------------------------------------------------
> *From:* Dr. Gerald N. Johnson <geraldj at weather.net>
> *To:* mams at mailman.qth.net
> *Sent:* Thu, January 6, 2011 10:25:59 AM
> *Subject:* Re: [MAMS] PLL
>
> The output frequency is 60 times the crystal frequency as marked. My
> first guess is that its a knock off of the common Frequencies West PLL.
> Which would be locking a power voltage controlled oscillator in the 1.5
> to 2 GHz region to to a crystal harmonic, then picking off the 3rd or
> 4th harmonic of that oscillator with a step recovery diode and filter.
> 15th harmonic of the crystal is 1.581.6 MHz and the 20th is 21080.8 GHz.
> FW blocks tend to drive the phase detector with the second harmonic of
> the crystal (e.g. 2x) so the second scheme is more likely. As it sits
> the output is 566.54 MHz above 5760, an inconvenient IF frequency. 4
> times the output is 25306.16, 1114.160 above 24192, not a great IF
> frequency.
>
> It might be possible to tune the VCO to pick off different harmonics of
> the existing crystal, but changing the crystal is probably practical, if
> one can work out the crystal parameters to get one with adequate
> frequency stability. And it may be possible to tune the output filter to
> a different frequency or maybe even harmonic if the presumed VCO range.
>
> With the range rated as 5.8 to 7.2 I presume the output filter and the
> VCO will tune at least that far, so its probable that without changing
> the crystal to tune to all even (based on FW details) harmonics of the
> crystal in the VCO range and multiply the VCO by factors of 3, 4, or
> maybe 5 by retuning the VCO and the output filter.
>
> In that collection of units, its probably that not all have the same
> frequency crystal. Its very likely possible to change the crystal for
> $30 or 40 buck a crystal to get a handier frequency though the handiest
> application for a 6 GHz range unit has been either a 5760 beacon or
> using the second harmonic for 24 GHz LO with half frequency injection.
>
> The other unhandy thing about FW blocks is that they mostly run on -20
> volts.
>
> 73, Jerry, K0CQ
>
> On 1/6/2011 9:33 AM, maryboller wrote:
>  > I have a Harris microwave pll for 5.8 to7.2 GHz, and I know where
> there are
>  > several more like it at reasonable prices. I have absolutely no
> information
>  > whatsoever on how to hook it up or power it. There are five wires
> going in.
>  >
>  > The model number is SD110009-106 S/n is 14 and the date code is 1196.
> There is a
>  > website called Star Microwave that lists it. but I have not been able
> to bring
>  > up any info. I am also pretty sure that the contacts I had at Harris
> 20 years
>  > ago are long gone. So, the questions are: Is it usable for ham
> frequencies. I
>  > sent it to Randy, WB0JQQ and he is not sure if it can be retuned
> without a new
>  > crystal. The frequencies listed on the outside that are adjustable are
>  > 6326.540mhz and 105.44233 mhz. I also aquired an lna from the same
> equipment and
>  > it really works good. It is so well built you could drive over it
> with a car and
>  > not damage it at all.
>  > Anybody : Recognize the PLL: have any printed info on it: know where
> info can
>  > be obtained:. I will ship it to anyone who might be interested in reverse
>  > engineering it
>  > Wally Boller, W9OBG
>  >
>  >
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