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 on: Yesterday at 05:46:13 PM 
Started by AK4YH - Last post by AA2UK
All good things to ponder. Here's one I thought of today.....
The 9700 is a higher frequency clone of the successful 7300. I have one and it's a great radio.

Now, picture a VHF/UHF clone to match the highly anticipated 7610. I have a 7610 on pre-order and would buy a higher frequency companion to it in a heartbeat. That way, I could sell my 271/471 radios.

Ron, the 7610 and 9700 look like really nice rigs
Bill, AA2UK

 on: Yesterday at 05:26:52 PM 
Started by AF6LJ - Last post by KM1H
Those who understand the subject agree with it. The time required to implement it is tiny. The cost is nearly zero.

Understanding includes evaluating the need which the lemmings dont understand. "Gee, if xxx says it is good I must do it even if I dont understand most details as my amp experience is minimal"

The shroud doesn't know what motor or fan blade is being used. The improvement works for both.

Ive seen about 3 different so called experts publish very different shroud dimensions for the same amp. If this thread goes long enough there will likely be more. Roll Eyes

A Canadian ham & EE developed a 2-speed fan concept. It's OK, except for manual control. Temperature and PTT control is automagic.

My 1986 LK-500ZC came standard with automatic temperature and PTT activated fan speed and so did a few others in the product line. Manual, or optional were other choices.
By that time some vehicles were also 2 speed and is also included in the better equipped Street Rods. I added it to my 38 Buick Roadmaster when the Nailhead was replaced with a 455.

 on: Yesterday at 05:14:18 PM 
Started by K1EBU - Last post by PLANKEYE
I don't know exactly what to say with all of these topics about getting a license by paying someone or the lack of FCC enforcement once you do have one.  What's this ham radio deal all about everything is starting to go in circles here.  Some are super hams and others are talking about paying to get their license and some even giving it up.  Holy cow. 

 on: Yesterday at 05:02:20 PM 
Started by AF6LJ - Last post by WA7PRC
That's why I posted a link to K5DBX's post and data showing an improvement in airflow. Also, my own observation indicates a noticeable reduction in noise. Even better, it costs only pennies and very little effort to implement.
That info is ancient history and very much ignored by those who understand the subject. With 10K or so amps produced and a high percentage in daily use some off the wall Hammy Hambone mod is a waste of time and money if a good Heath fan is replaced by a Harbach.
Those who understand the subject agree with it. The time required to implement it is tiny. The cost is nearly zero.
So, let's not try to easily improve the margin. And, let's not try to reduce the noise.
Nobody forced you to buy an overkill fan from Harbach. You could also have added a two speed switch mod as in Dentron, Amp Supply, etc. I did that to my Hunter Bandit 2000C which was really loud.

I might agree if the amp was in the Negev at high noon and outside but Id also question the sanity of anyone doing that.
The shroud doesn't know what motor or fan blade is being used. The improvement works for both.
A Canadian ham & EE developed a 2-speed fan concept. It's OK, except for manual control. Temperature and PTT control is automagic.
The insane person thinks everyone else is.

 on: Yesterday at 04:58:29 PM 
Started by ZL1BDA - Last post by ZL1BDA
Am just doing up this recently aquired radio and have solved my volume issues OK by realigning the IF and adjusting the AGC correctly.
Now I have just one problem. At some time a BFO crystal either failed or was removed from the board. I have quite a stock of crystals, but NOT one on
3.18150MHz. it is a standard HC6U type, but any type could be used and looks like a parallel resonant type with 20pF in parallel.
Has anyone got any good ideas for a source of one of these? I don't think that I will ever need more than one!!!
Odd that Japanese made gear uses so many different IF frequencies.

 on: Yesterday at 04:53:30 PM 
Started by W6TGE - Last post by AA2UK
I roll my own too but I did load rc2 to play with it. By building your own you retain all the features of V1.8.0 rc2 with all the latest upgrades. I just got finished building r8111.
AA2UK, Bill

 on: Yesterday at 04:52:44 PM 
Started by W8ASI - Last post by PLANKEYE
Ya know I read this and all the comments and I thought about how it must feel to want to cancel your license.  I mean I get he posted the question and then went on to explain why he hates radio.  I get that.  Tisha says don't let the door hit you on the way out and some others pretty much say get out we don't need you blah blah.  I have been listening on the air for a while now and I have been wondering why folks can use a legit callsign and get away with what they say on the air.  Is the FCC awake or are they napping?  I guess it has been going on for a while I ran across a old E-ham article I hate 75 meters by I think w8mw from 2001 but I'm not sure of the call.  It was satire but the comments were not.  What I hear on the air at least on 80 mtrs and 40 mtrs  phone sounds like the FCC is napping.  Even in the extra part of both bands except CW with that mode all is nice.  It's too bad that folks get to the point that they want to forfeit their license.  If the FCC won't do anything about it can't everyone in the ham community like be a neighborhood watch.  Self police these crazy people so to speak?  I'm just asking but it's again too bad that folks want to forfeit a ticket.  What can you do to help stop this?   

 on: Yesterday at 04:49:28 PM 
Started by K7QA - Last post by K4SAV
There are various versions of the DHDL antenna.  The plot and RDF I gave you was for 17.8 ft vertical wires at 2 ft above ground.  The spacing of the vertical wires was 87 ft.  That is a lot easier to build.  The termination resistor was 1200 ohms and the feedpoint impedance is close to 950 ohms.

Yes RDF is a measure of directivity.  Directivity says a lot about the pattern of an antenna.  It says nothing about antenna gain.  If you need more gain, just add a preamp, but that preamp doesn't change the S/N (unless the preamp is poor and contributes noise). 

Atmospheric noise is assumed to be coming from all directions, which is not always true but it could be, and that is a good assumption when designing a receiving antenna.  The only way you can reduce that noise and improve the S/N is to make the antenna pattern have max gain in the direction of the station and minimum gain in all other directions.  The RDF number is a measure of that characteristic.  RDF isn't perfect but it is very useful.  ON4UN developed a different metric and that is DMF (Directivity Merit Factor), which gives more weight to the antenna response in the rear half of the pattern.  It is a lot more trouble to calculate.  The RDF (Receiving Directivity Factor) is easy since EZNEC will calculate it directly.

Jerry, K4SAV

 on: Yesterday at 04:47:48 PM 
Started by K9AQ - Last post by KM1H
Going from 12 to 24/28V and then to 50V and up was a big step in the IMD wars. This includes going from bipolar to Mosfet.

 on: Yesterday at 04:43:58 PM 
Started by KG4ABA - Last post by AA2UK
As I said I own my home so no landlord issues there. I'm not staying here more than a few years. My hard line, rotor cable and LMR cables run thru a 4" EMS Wireless cable entry boot assembly in the cieling into the attic then out to the roof through a side wall next to the 2nd story gable/ attic vent using another EMS Wireless plate/ boot.
I actually had the heavy gauge Carol rubberized stranded cable assembly for the 220 circuit given to me. I misspoke the cable is #8 with 4 stranded wires. I purchased the 14-50R Dryer plug and Hubbel 50A twist lock connectors/ plugs from HD. This circuit feeds a Swan Mark6B and a 60 AMP 48VDC Cell Site switching supply used for a 2 meter W6PQL BLF188XR amp and a commercial 1kw 220-435Mhz Class A amplifier.
But it's not about me I was just offering a safe alternative to the thread. I had no additional breaker positions on my house panel so the dryer circuit works great as long as my XYL isn't drying clothes. If the bands are open the clothes have to wait...
AA2UK, Bill

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