[Premium-Rx] Electro-Metrics EM-8500 Demodulator

[Mark Donaldson]

Hi Spencer,

I'm afraid I can't be of much help to you on this but
thanks for bringing it to our attention, I own one of
the HP spectrum analyzers that it is meant to work
with and this looks like the perfect accessory for
microwave signal monitoring. I notice that the last
one that sold on eBay came from a dealer in Annapolis
so I can easily guess at what some of these were used
for and who was using them. I did find a place on the
web that will rent you an operator manual for $25
dollars which seems quite reasonable. 

http://www.consolidatedsurplus.com/index.cfm/fuseaction/product.display/product_id/173893/index.cfm

Finally it looks like you could use this with 10.7MHz
IF output by building a simple upconverter to 310.7
MHz, just take a 100MHz xtal oscillator run it into a
saturated MMIC amp to get a strong third harmonic and
use this as the LO into a mixer. You may need to
highpass or bandpass filter the RF output but this
would not be much of a challenge to do with discrete
components. I would not be surprised if you dug into
the box that you would find that it has a 10.7MHz IF
that you can couple into directly. 

Let us know if you get any more info on this unit.

Mark Donaldson   WA1QHQ

--- spencer bahner <spencer12345 at msn.com> wrote:

> Does anyone out there have any experience playing
> with the EM-8500 demods 
> that have been showing up on Epay of late? I bought
> one that seems to work 
> with the though that I need to buy an HP
> more-or-less portable spectrum 
> analyser anyway. Having demod capability would be
> useful for the land-mobile 
> work I do... The second IF input appears useful for
> use with WJ microwave 
> receivers that lack narrowband demods.
> 
> Here is the basic info on my unit:
> 
> Two IF inputs: 310.7 MHz and 160 MHz
> These were for use with HP spectrum analyzers
> mentioned above (310.7 MHz 
> input) or I would guess microwave intercept
> receivers (160 MHz IF input). 
> Sadly no 21.4 MHz or 10.7 MHz!
> 
> Has the following 'normal' IF bandwidths:
> 
> 300 KHz AM/FM
> 150 KHz AM/FM
> 20 KHz AM/FM/CW/USB/LSB
> 10 KHz AM/FM/CW/USB/LSB
> 3.2 KHz AM/FM/CW/USB/LSB
> 1.0 KHz AM/FM/CW/USB/LSB
> 0.2 KHz AM/FM/CW/USB/LSB
> 
> BFO for use with CW/SSB modes. Also has subcarrier
> demod for subcarrier 
> analysis and bug detection. Sensitivity is on the
> order of 1-1.5 uV/12 db 
> SINAD for 20 KHz FM.
> 
> Anyone have one of these? Anyone have a manual or
> bought a manual from 
> Electro-Metrics? EM appears to have a similar or
> identical model but under a 
> different model number.
> 
> Send me any info or thoughts you might have on
> these!
> 
> Thanks.
> 
> Spencer Bahner N7UMO
> Seattle
> spencer12345 at msn.com
> 
> 
> 
> _______________________________________________
> 
> Premium-Rx Mailing List
> To Post: premium-rx at ml.skirrow.org
> For Info:
> http://ml.islandnet.com/mailman/listinfo/premium-rx
> Visit the Website:
> http://kahuna.sdsu.edu/~mechtron/PremRxPage/
> 



 
____________________________________________________________________________________
Have a burning question?  
Go to www.Answers.yahoo.com and get answers from real people who know.