[TenTec] F.S. New Ten Tec 715 RF Processor
Bob McGraw - K4TAX
RMcGraw at Blomand.net
Tue Feb 18 23:01:55 EST 2014
In my use and testing on the bench, I did find that the 715 does exactly
what it is designed and advertised to do and that is to limit the transmit
audio bandwidth and compress the dynamic range thus raise the average PEP
The frequency response of the unit: With the passband control centered is -
3dB @ 800 Hz to -3dB @ 4500 Hz. With the passband full clockwise the
response is -3 dB @ 450 Hz to -3 dB @ 4500Hz and with the passband control
counterclockwise the response is -3 dB @ 1300 Hz to -3 dB @ 4500 Hz. These
values typically make for a "loud and piercing sounding" signal generally
good for being heard in a DX pileup.
On VOX usage:
Do note that using a processor with a radio having the VOX active makes for
challenge to get the VOX Gain correct due to the variable gain from
processing ahead of the VOX circuit. Internally when using VOX control the
mike signal is split two ways, one that goes to the transmitter side and one
that goes to the VOX amp side. Thus any EQ or processing internal to the
radio is applied only to the transmit side. With the external processor,
the processed audio is applied to both the transmit and VOX amps.
----- Original Message -----
From: "GARY HUBER" <glhuber at msn.com>
To: "Brian Carling AF4K" <bcarling at cfl.rr.com>; "Discussion of Ten-Tec
Equipment" <tentec at contesting.com>
Sent: Tuesday, February 18, 2014 9:09 PM
Subject: Re: [TenTec] F.S. New Ten Tec 715 RF Processor
> Set your radio mic gain with the TT-715 in the OUT position. The TT-715
> has an output level setting on the back. With the PROC Gain set to about
> seven o'clock or just about 6 dB of clipping you should set the output
> level so the radio's peak RF output is the same when the TT-715 is IN as
> when it is OUT. Once you have that output level set correctly, you can
> change the pass band and proc gain. There's plenty of gain in the TT-715
> making it easy to over drive the radio. Amplified, rising response, and
> hi-output microphones should be used cautiously with the TT-715.
> I find using a separate receiver to make recordings for playback is the
> best way for me to make TT-715 Passband and level adjustments with various
> 73 ES DX,
> Gary -- AB9M
> -----Original Message-----
> From: Bry Carling
> Sent: Tuesday, February 18, 2014 8:12 PM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] F.S. New Ten Tec 715 RF Processor
> OK thanks - interesting. Who knows then. Must be something magic about
> those Tentec
> microphones and processors.
> It could be that the signal level is vastly different from what is
> expected by the processor. Or it
> could be that the signal level coming out of the processor is suitable for
> a Tentec radio but
> NOT suitable for the Drake radios etc. It certainly sounds to me like
> something was
> overdriving somewhere. You may have had some levels set wrong. Generally
> you want to run
> the mic gain in the radio a little higher, and reduce the drive level
> going into it. With the
> processor it wil lbe very important to use the correct drive level for
> your mic signal going into
> it, and have it be at the expected impedance. Any overdriving at any stage
> will produce some
> rough sounding audio.
> 73 de AF4K, Bry
> On 18 Feb 2014 at 17:35, Joe W2KJ wrote:
>> Howdy Bry:
>> The 444D can be switched between HI and LO impedance...so that's not
>> the problem...I also used a 600 ohm headset with similar
>> results....it's not a mike impedance problem.
>> 73, Joe W2KJ
>> On Feb 18, 2014, at 4:20 PM, Brian Carling wrote:
>> > It sounds like you might possibly have had an impedance mismatch.
>> Most attend tech equipment and other modern equipment uses low
>> impedance microphones, around 600 ohms.
>> > If you use microphones like the Shure 444 and other high impedance
>> microphones, they can be loaded down and sound pretty terrible.
>> > Best regards - Bry Carling
>> >> On Feb 18, 2014, at 4:06 PM, Joe W2KJ <w2kj at bellsouth.net>
>> >> Howdy Gang:
>> >> Last year I bought a model 715 RF Speech Processor from Ten Tec
>> and played with it for several months with my Drake gear but
>> couldn't get the audio to sound good.
>> >> A couple of weeks ago I called Ten Tec to let them know that the
>> 715 wasn't working well with my Drake gear so they told me to send
>> the unit back to them for a look-see.
>> >> I received a brand new unit last week and still had the same
>> problem of poor audio with my Drake gear...using a 444D mike
>> provided excellent audio with the Drake stuff but not through the
>> >> Since the 30 day return policy was no longer in effect I couldn't
>> get a refund from Ten Tec.
>> >> I was told by a Ten Tec rep that a similar complaint was received
>> from an amateur not getting good audio from his Collins gear with
>> the 715.
>> >> I guess the 715 is designed to work with newer gear...I have also
>> heard that the 715 was designed to work FB with more "restricted
>> audio" microphones...not sure exactly what that means though.
>> >> The 715 gets excellent reviews on eHam Product Reviews..all using
>> newer equipment not vintage gear.
>> >> In any event, I appreciate the support I received from Ten Tec
>> and have decided to sell the 715 since I can't use it with my Drake
>> >> I offer the unit for sale...it is brand new.....will ship for
>> >> It comes with a cable designed for Ten Tec equipment.
>> >> Digital picture on request.
>> >> Many thanks.
>> >> 73, Joe W2KJ
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