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Re: TR7 next problem
Gary I tried that ground on RFC505 and no change. Is it not getting band information? Jim VE1RB [email protected]> wrote:
By Jim Harris · #81466 ·
Re: TR7 next problem
Okay Gary I will go do that right now. Jim VE1RB [email protected]> wrote:
By Jim Harris · #81465 ·
Re: TR7 next problem
On Wed, Jan 1, 2025 at 12:52?PM Jim Harris <radiove1rb@...> wrote: > Good ideas Jim and I will get at doing that today. It is windy and raining > here quite hard. A good job inside hi hi. I
By Jim Harris · #81464 ·
Re: VE3EFJ third mixer mod for the R4C
Jim, thanks for the reminder. Wow, Oshpark now wants USD $53.60 per 3-board order. It's much less expensive through JLCPCB at USD $3.50 for five boards and includes Global Standard Postal (i.e., slow)
By Paul Christensen · #81463 ·
Re: TR7 next problem
If you are reading 152 MHz, the you should ground RFC505 on the end away from the varactor diodes. The frequency should come down. Gary W0DVN
By Gary Follett · #81462 ·
Re: VE3EFJ third mixer mod for the R4C
*** I haven't had good luck with those. They market them as over 10W, but they're really only capable of 1W, running off 12V. And the onboard electrolytics are only 16V, so you are limited to that.
By jerry-KF6VB · #81461 ·
AMP-4
Mr. Rob... Can you please remind me what the low frequency attenuation was for your AMP-4? Thanks! Joseph
By Joseph K7CBR <k7cbr@...> · #81460 ·
Re: Speaker?
Spot on... As I stated in my group posting, the original driver is old, and a less efficient speaker can be had when using more power. My MS-4 was treated to a hardwood ply escutcheon to mount the
By Joseph K7CBR <k7cbr@...> · #81459 ·
Re: Speaker?
Frank, I am running the audio out of my R4C into a CLEAR SPEECH noise filter, then....from the noise filter into a Kenwood SP-940 speaker with 3 filters in it. Absolute Nirvana sound...Can pick up
By Bill Losef · #81458 ·
Re: TR7 next problem
Jim I just hooked my older counter and it is reading 152 MHZ plus it minus. Now which one is right? Maybe this one where the voltage is so high. Maybe I should put a ground on RFC505 and see what
By Jim Harris · #81457 ·
Re: TR7 next problem
Forget that idea as I turned the TR7 off and that frequency did not go away. Guess next it to try and measure voltages on both VCO¡¯s and see if that will show the bad part etc. Jim VE1RB
By Jim Harris · #81456 ·
Re: VE3EFJ third mixer mod for the R4C
My AMP-4 feedback loop was designed for about a 3 dB roll-off at 3 kHz. Personal choice. Rob, NC0B
By Rob Sherwood · #81455 ·
Re: TR7 next problem
Jim maybe this will help. I touched up several solder joints although they didn¡¯t look good but not cracked. I switched the input to the counter and it is reading 17 to 18 mhz as the frequency is
By Jim Harris · #81454 ·
Re: Speaker?
All the talk about the audio amplifier on an R-4C intrigues me to ask the question, ¡°What are you doing about the speaker?¡± With a 50 year old speaker in some cases, what are you replacing it
By Frank KG9H · #81453 ·
Re: AF AMP VE3EFJ third mixer mod for the R4C
Gary!!! Bravo! I too used a device like that for mine( TDA7377)... I removed the original jensen speaker, used a lower efficiency driver, yet one with better listening specs. My MS-4 has been modified
By Joseph K7CBR <k7cbr@...> · #81452 ·
Re: VE3EFJ third mixer mod for the R4C
I've seen that board on Osh Park. I like the purple one. :D "Paul Christensen via groups.io" <w9ac@...> wrote: -- 73 -Jim NU0C
By Jim Shorney · #81451 ·
Re: VE3EFJ third mixer mod for the R4C
Yeah, that works. The TDA chips are rock stable and practically bulletproof when implemented properly. I have one of the Velleman TDA2002 modules that I acquired some years back for my R4C, I just
By Jim Shorney · #81450 ·
Re: VE3EFJ third mixer mod for the R4C
The TDA series and LM380 are fine although I wanted lower noise with no detectable hiss at any setting of the AF control when using studio-grade headphones. The image below shows a discrete class AB
By Paul Christensen · #81449 ·
Re: TR7 next problem
Good ideas Jim and I will get at doing that today. It is windy and raining here quite hard. A good job inside hi hi. I will let you know how it goes. Many thanks for the suggestions and help. Jim
By Jim Harris · #81448 ·
Re: VE3EFJ third mixer mod for the R4C
It's a waste of time and money to design an AF amp for the Drake. I used a (now) 75cent complete TDA2030 module from china. Like this one:
By Gary WB6OGD · #81447 ·