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As I recall the Simba used a model 90-5 and not a 90-1. Not sure what the difference was between all the different models, but they all pretty much installed the same way. Remove the crystal that controls channel 23 (that would be the 11.250 MHz crystal on the Simba) and connect the VFO wires to this now-empty slot.

More information on Siltronix VFOs here: http://www.cbtricks.com/miscellaneous/vco/siltronix/model_90/graphics/siltronix_vfo_model_90_om.pdf

Oh one other thing: Never turn the VFO off even when you shut down the rest of the system. Silkie VFOs are famous for drifting and turning them on and off will only make it worse. Also watch out for ground loops, characterized by a 'warbling' sound in your transmit audio on sideband.

Expect to have to retune the receiver to accept the broader receive frequency range. Radios that have high 'Q' tend not to broadband very well and this causes receiver function to drop off on the higher frequencies.

Have fun with it!

<blockquote data-quote="Atlasta" data-source="post: 381376" data-attributes="member: 19597">As I recall the Simba used a model 90-5 and not a 90-1.&nbsp; Not sure what the difference was between all the different models, but they all pretty much installed the same way.&nbsp; Remove the crystal that controls channel 23 (that would be the 11.250 MHz crystal on the Simba) and connect the VFO wires to this now-empty slot.&nbsp; More information on Siltronix VFOs here: <a href="http://www.cbtricks.com/miscellaneous/vco/siltronix/model_90/graphics/siltronix_vfo_model_90_om.pdf" target="_blank">http://www.cbtricks.com/miscellaneous/vco/siltronix/model_90/graphics/siltronix_vfo_model_90_om.pdf</a>Oh one other thing:&nbsp; Never turn the VFO off even when you shut down the rest of the system.&nbsp; Silkie VFOs are famous for drifting and turning them on and off will only make it worse.&nbsp; Also watch out for ground loops, characterized by a &#039;warbling&#039; sound in your transmit audio on sideband.Expect to have to retune the receiver to accept the broader receive frequency range.&nbsp; Radios that have high &#039;Q&#039; tend not to broadband very well and this causes receiver function to drop off on the higher frequencies.&nbsp; Have fun with it!</blockquote>

[QUOTE="Atlasta, post: 381376, member: 19597"] As I recall the Simba used a model 90-5 and not a 90-1. Not sure what the difference was between all the different models, but they all pretty much installed the same way. Remove the crystal that controls channel 23 (that would be the 11.250 MHz crystal on the Simba) and connect the VFO wires to this now-empty slot. More information on Siltronix VFOs here: [url]http://www.cbtricks.com/miscellaneous/vco/siltronix/model_90/graphics/siltronix_vfo_model_90_om.pdf[/url] Oh one other thing: Never turn the VFO off even when you shut down the rest of the system. Silkie VFOs are famous for drifting and turning them on and off will only make it worse. Also watch out for ground loops, characterized by a 'warbling' sound in your transmit audio on sideband. Expect to have to retune the receiver to accept the broader receive frequency range. Radios that have high 'Q' tend not to broadband very well and this causes receiver function to drop off on the higher frequencies. Have fun with it! [/QUOTE]

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