You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Reply to thread

Message

Pride RF Input Circuit Copy

Initial results from my copy of the Pride RF input circuit are encouraging to the extent that I see improvement on 10-11-15. 20M continues to be a dead zone. I note the Pride plate choke was 55uH while the Ameritron-ish AL-572 choke I’m using is about 200uH. (RF Parts purchase pre-2010).

Amp is still on work table so all results are into a DL and powered by low current AC outlet. Plate current is limited to the single chassis-mounted transformer (1.8kv @ 400mA).

The RF input I had previously was a 1:6 unun, RF grounded with a 300 ohm swamping resistance to RF ground. It provided only 1 value of inductance (the unun coil to RF ground itself) for every band. The Pride input circuit allows me to select a different inductance to RF ground for each band. A 4PSP switch allows for a different inductance to RF ground for each band (10-11-20-40). I also added a series connected, slug tuned inductor (1.5 to 1.8uF) I can switch in and out via a toggle to add some to each position for comparison.

I’m still unfamiliar with the new and higher drive level imposed by Pride 750 ohm swamping resistance. I expected drive requirements to decrease from the higher 750 swamping resistance. While the Pride values were for 1 tube and I have 2 tubes, 750 is still more than double 300 ohms.

In any event, I’m working on the presumption I can double the Pride drive limits because I run 2 tubes instead of 1. (10w AM / 25w PEP)
Gotta run later,
neil, NYC

<blockquote data-quote="Naysayer" data-source="post: 841628" data-attributes="member: 57429">Pride RF Input Circuit CopyInitial results from my copy of the Pride RF input circuit are encouraging to the extent that I see improvement on 10-11-15.&nbsp;&nbsp; 20M continues to be a dead zone.&nbsp; I note the Pride plate choke was 55uH while the Ameritron-ish AL-572 choke I’m using is about&nbsp; 200uH. (RF Parts purchase pre-2010).&nbsp; Amp is&nbsp; still on work table so all results are into a DL and powered by&nbsp; low current AC outlet.&nbsp; Plate current is limited to the single chassis-mounted transformer (1.8kv @ 400mA). The RF input I had previously was a 1:6 unun, RF grounded with&nbsp; a 300 ohm swamping resistance to RF ground.&nbsp; It provided only 1 value of inductance (the unun coil to RF ground itself) for every band.&nbsp; The Pride input circuit allows me to select&nbsp; a different inductance to RF ground for each band.&nbsp; A 4PSP&nbsp; switch allows for a different&nbsp; inductance to RF ground for each band (10-11-20-40).&nbsp; I also added a series connected, slug tuned inductor (1.5 to 1.8uF)&nbsp; I can switch in and out via&nbsp; a toggle to add some to each position for comparison.&nbsp; I’m still unfamiliar with the new and higher drive level imposed by Pride&nbsp; 750 ohm swamping resistance.&nbsp; I expected drive requirements to decrease from the higher 750 swamping resistance.&nbsp;&nbsp; While&nbsp; the&nbsp; Pride values&nbsp; were for 1 tube and I have 2 tubes, 750 is still more than double&nbsp; 300 ohms.&nbsp; &nbsp; In any event, I’m working on the presumption I can double the Pride drive limits because I run 2 tubes instead of 1. (10w AM / 25w PEP) Gotta run later,&nbsp;neil, NYC</blockquote>

[QUOTE="Naysayer, post: 841628, member: 57429"] [B]Pride RF Input Circuit Copy[/B] Initial results from my copy of the Pride RF input circuit are encouraging to the extent that I see improvement on 10-11-15. 20M continues to be a dead zone. I note the Pride plate choke was 55uH while the Ameritron-ish AL-572 choke I’m using is about 200uH. (RF Parts purchase pre-2010). Amp is still on work table so all results are into a DL and powered by low current AC outlet. Plate current is limited to the single chassis-mounted transformer (1.8kv @ 400mA). The RF input I had previously was a 1:6 unun, RF grounded with a 300 ohm swamping resistance to RF ground. It provided only 1 value of inductance (the unun coil to RF ground itself) for every band. The Pride input circuit allows me to select a different inductance to RF ground for each band. A 4PSP switch allows for a different inductance to RF ground for each band (10-11-20-40). I also added a series connected, slug tuned inductor (1.5 to 1.8uF) I can switch in and out via a toggle to add some to each position for comparison. I’m still unfamiliar with the new and higher drive level imposed by Pride 750 ohm swamping resistance. I expected drive requirements to decrease from the higher 750 swamping resistance. While the Pride values were for 1 tube and I have 2 tubes, 750 is still more than double 300 ohms. In any event, I’m working on the presumption I can double the Pride drive limits because I run 2 tubes instead of 1. (10w AM / 25w PEP) Gotta run later, neil, NYC [/QUOTE]

Top Bottom